Espruino Software Reference

Version 2v05.5

Contents

Globals

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Methods and Fields

function analogRead

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Call type:

function analogRead(pin)

Parameters

pin - The pin to use
You can find out which pins to use by looking at your board's reference page and searching for pins with the ADC markers.

Returns

The analog Value of the Pin between 0 and 1

Description

Get the analog value of the given pin

This is different to Arduino which only returns an integer between 0 and 1023

However only pins connected to an ADC will work (see the datasheet)

Note: if you didn't call pinMode beforehand then this function will also reset pin's state to "analog"

Examples

This function is used in the following places in Espruino's documentation

function analogWrite

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Call type:

function analogWrite(pin, value, options)

Parameters

pin - The pin to use
You can find out which pins to use by looking at your board's reference page and searching for pins with the PWM or DAC markers.

value - A value between 0 and 1

options - An object containing options for analog output - see below

Description

Set the analog Value of a pin. It will be output using PWM.

Objects can contain:

Note: if you didn't call pinMode beforehand then this function will also reset pin's state to "output"

Examples

This function is used in the following places in Espruino's documentation

variable arguments

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Call type:

variable arguments

Returns

An array containing all the arguments given to the function

Description

A variable containing the arguments given to the function:

function hello() {
  console.log(arguments.length, JSON.stringify(arguments));
}
hello()        // 0 []
hello("Test")  // 1 ["Test"]
hello(1,2,3)   // 3 [1,2,3]

Note: Due to the way Espruino works this is doesn't behave exactly the same as in normal JavaScript. The length of the arguments array will never be less than the number of arguments specified in the function declaration: (function(a){ return arguments.length; })() == 1. Normal JavaScript interpreters would return 0 in the above case.

function atob

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Call type:

function atob(base64Data)

Parameters

base64Data - A string of base64 data to decode

Returns

A string containing the decoded data

Description

Decode the supplied base64 string into a normal string

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

Bluetooth

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Instance of Serial

Description

The Bluetooth Serial port - used when data is sent or received over Bluetooth Smart on nRF51/nRF52 chips.

Note: This is only available in devices with Bluetooth LE capability

variable BTN

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Call type:

variable BTN

Returns

Button 1

variable BTN1

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Call type:

variable BTN1

Returns

BTN1

variable BTN2

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Call type:

variable BTN2

Returns

BTN2

variable BTN3

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Call type:

variable BTN3

Returns

BTN3

variable BTN4

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Call type:

variable BTN4

Returns

BTN4

variable BTN5

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Call type:

variable BTN5

Returns

BTN5

function btoa

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Call type:

function btoa(binaryData)

Parameters

binaryData - A string of data to encode

Returns

A base64 encoded string

Description

Encode the supplied string (or array) into a base64 string

Note: This is not available in devices with low flash memory

function changeInterval

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Call type:

function changeInterval(id, time)

Parameters

id - The id returned by a previous call to setInterval

time - The new time period in ms

Description

Change the Interval on a callback created with setInterval, for example:

var id = setInterval(function () { print('foo'); }, 1000); // every second

changeInterval(id, 1500); // now runs every 1.5 seconds

This takes effect immediately and resets the timeout, so in the example above, regardless of when you call changeInterval, the next interval will occur 1500ms after it.

Examples

This function is used in the following places in Espruino's documentation

function clearInterval

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Call type:

function clearInterval(id, ...)

Parameters

id, ... - The id returned by a previous call to setInterval

Description

Clear the Interval that was created with setInterval, for example:

var id = setInterval(function () { print('foo'); }, 1000);

clearInterval(id);

If no argument is supplied, all timeouts and intervals are stopped.

To avoid accidentally deleting all Intervals, if a parameter is supplied but is undefined then an Exception will be thrown.

Examples

This function is used in the following places in Espruino's documentation

function clearTimeout

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Call type:

function clearTimeout(id, ...)

Parameters

id, ... - The id returned by a previous call to setTimeout

Description

Clear the Timeout that was created with setTimeout, for example:

var id = setTimeout(function () { print('foo'); }, 1000);

clearTimeout(id);

If no argument is supplied, all timeouts and intervals are stopped.

To avoid accidentally deleting all Timeouts, if a parameter is supplied but is undefined then an Exception will be thrown.

Examples

This function is used in the following places in Espruino's documentation

function clearWatch

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Call type:

function clearWatch(id, ...)

Parameters

id, ... - The id returned by a previous call to setWatch

Description

Clear the Watch that was created with setWatch. If no parameter is supplied, all watches will be removed.

To avoid accidentally deleting all Watches, if a parameter is supplied but is undefined then an Exception will be thrown.

Examples

This function is used in the following places in Espruino's documentation

function decodeURIComponent

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Call type:

function decodeURIComponent(str)

Parameters

str - A string to decode from a URI

Returns

A string containing the decoded data

Description

Convert any groups of characters of the form '%ZZ', into characters with hex code '0xZZ'

Note: This is not available in devices with low flash memory

function digitalPulse

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Call type:

function digitalPulse(pin, value, time)

Parameters

pin - The pin to use

value - Whether to pulse high (true) or low (false)

time - A time in milliseconds, or an array of times (in which case a square wave will be output starting with a pulse of 'value')

Description

Pulse the pin with the value for the given time in milliseconds. It uses a hardware timer to produce accurate pulses, and returns immediately (before the pulse has finished). Use digitalPulse(A0,1,0) to wait until a previous pulse has finished.

eg. digitalPulse(A0,1,5); pulses A0 high for 5ms. digitalPulse(A0,1,[5,2,4]); pulses A0 high for 5ms, low for 2ms, and high for 4ms

Note: if you didn't call pinMode beforehand then this function will also reset pin's state to "output"

digitalPulse is for SHORT pulses that need to be very accurate. If you're doing anything over a few milliseconds, use setTimeout instead.

Examples

This function is used in the following places in Espruino's documentation

function digitalRead

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Call type:

function digitalRead(pin)

Parameters

pin - The pin to use

Returns

The digital Value of the Pin

Description

Get the digital value of the given pin.

Note: if you didn't call pinMode beforehand then this function will also reset pin's state to "input"

If the pin argument is an array of pins (eg. [A2,A1,A0]) the value returned will be an number where the last array element is the least significant bit, for example if A0=A1=1 and A2=0, digitalRead([A2,A1,A0]) == 0b011

If the pin argument is an object with a read method, the read method will be called and the integer value it returns passed back.

Examples

This function is used in the following places in Espruino's documentation

function digitalWrite

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Call type:

function digitalWrite(pin, value)

Parameters

pin - The pin to use

value - Whether to pulse high (true) or low (false)

Description

Set the digital value of the given pin.

Note: if you didn't call pinMode beforehand then this function will also reset pin's state to "output"

If pin argument is an array of pins (eg. [A2,A1,A0]) the value argument will be treated as an array of bits where the last array element is the least significant bit.

In this case, pin values are set least significant bit first (from the right-hand side of the array of pins). This means you can use the same pin multiple times, for example digitalWrite([A1,A1,A0,A0],0b0101) would pulse A0 followed by A1.

If the pin argument is an object with a write method, the write method will be called with the value passed through.

Examples

This function is used in the following places in Espruino's documentation

function dump

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Call type:

function dump()

Description

Output current interpreter state in a text form such that it can be copied to a new device

Note: 'Internal' functions are currently not handled correctly. You will need to recreate these in the onInit function.

Note: This is not available in devices with low flash memory

function echo

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Call type:

function echo(echoOn)

Parameters

echoOn -

Description

Should Espruino echo what you type back to you? true = yes (Default), false = no. When echo is off, the result of executing a command is not returned. Instead, you must use 'print' to send output.

function edit

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Call type:

function edit(funcName)

Parameters

funcName - The name of the function to edit (either a string or just the unquoted name)

Description

Fill the console with the contents of the given function, so you can edit it.

NOTE: This is a convenience function - it will not edit 'inner functions'. For that, you must edit the 'outer function' and re-execute it.

Examples

This function is used in the following places in Espruino's documentation

function encodeURIComponent

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Call type:

function encodeURIComponent(str)

Parameters

str - A string to encode as a URI

Returns

A string containing the encoded data

Description

Convert a string with any character not alphanumeric or - _ . ! ~ * ' ( ) converted to the form %XY where XY is its hexadecimal representation

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

function eval

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Call type:

function eval(code)

Parameters

code -

Returns

The result of evaluating the string

Description

Evaluate a string containing JavaScript code

Examples

This function is used in the following places in Espruino's documentation

function getPinMode

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Call type:

function getPinMode(pin)

Parameters

pin - The pin to check

Returns

The pin mode, as a string

Description

Return the current mode of the given pin. See pinMode for more information on returned values.

Note: This is not available in devices with low flash memory

function getSerial

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Call type:

function getSerial()

Returns

The board's serial number

Description

Get the serial number of this board

function getTime

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Call type:

function getTime()

Returns

See description above

Description

Return the current system time in Seconds (as a floating point number)

Examples

This function is used in the following places in Espruino's documentation

variable global

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Call type:

variable global

Returns

The global scope

Description

A reference to the global scope, where everything is defined.

variable HIGH

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Call type:

variable HIGH

Returns

Logic 1 for Arduino compatibility - this is the same as just typing 1

I2C1

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Instance of I2C

Description

The first I2C port

Note: This is only available in devices with more than 1 I2C peripherals

variable Infinity

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Call type:

variable Infinity

Returns

Positive Infinity (1/0)

function isFinite

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Call type:

function isFinite(x)

Parameters

x -

Returns

True is the value is a Finite number, false if not.

Description

Is the parameter a finite num,ber or not? If needed, the parameter is first converted to a number.

function isNaN

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Call type:

function isNaN(x)

Parameters

x -

Returns

True is the value is NaN, false if not.

Description

Whether the x is NaN (Not a Number) or not

Examples

This function is used in the following places in Espruino's documentation

variable LED

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Call type:

variable LED

Returns

A Pin object for a fake LED which appears on

Description

On most Espruino board there are LEDs, in which case LED will be an actual Pin.

On Bangle.js there are no LEDs, so to remain compatible with example code that might expect an LED, this is an object that behaves like a pin, but which just displays a circle on the display

Note: This is only available in Bangle.js smartwatches

variable LED1

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Call type:

variable LED1

Returns

A Pin object for a fake LED which appears on

Description

On most Espruino board there are LEDs, in which case LED1 will be an actual Pin.

On Bangle.js there are no LEDs, so to remain compatible with example code that might expect an LED, this is an object that behaves like a pin, but which just displays a circle on the display

Note: This is only available in Bangle.js smartwatches

variable LED2

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Call type:

variable LED2

Returns

A Pin object for a fake LED which appears on

Description

On most Espruino board there are LEDs, in which case LED2 will be an actual Pin.

On Bangle.js there are no LEDs, so to remain compatible with example code that might expect an LED, this is an object that behaves like a pin, but which just displays a circle on the display

Note: This is only available in Bangle.js smartwatches

function load

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Call type:

function load(filename)

Parameters

filename - optional: The name of a text JS file to load from Storage after reset

Description

Restart and load the program out of flash - this has an effect similar to completely rebooting Espruino (power off/power on), but without actually performing a full reset of the hardware.

This command only executes when the Interpreter returns to the Idle state - for instance a=1;load();a=2; will still leave 'a' as undefined (or what it was set to in the saved program).

Espruino will resume from where it was when you last typed save(). If you want code to be executed right after loading (for instance to initialise devices connected to Espruino), add an init event handler to E with E.on('init', function() { ... your_code ... });. This will then be automatically executed by Espruino every time it starts.

If you specify a filename in the argument then that file will be loaded from Storage after reset in much the same way as calling reset() then eval(require("Storage").read(filename))

LoopbackA

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Instance of Serial

Description

A loopback serial device. Data sent to LoopbackA comes out of LoopbackB and vice versa

LoopbackB

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Instance of Serial

Description

A loopback serial device. Data sent to LoopbackA comes out of LoopbackB and vice versa

variable LOW

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Call type:

variable LOW

Returns

Logic 0 for Arduino compatibility - this is the same as just typing 0

variable NaN

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Call type:

variable NaN

Returns

Not a Number

function parseFloat

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Call type:

function parseFloat(string)

Parameters

string -

Returns

The value of the string

Description

Convert a string representing a number into an float

Examples

This function is used in the following places in Espruino's documentation

function parseInt

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Call type:

function parseInt(string, radix)

Parameters

string -

radix - The Radix of the string (optional)

Returns

The integer value of the string (or NaN)

Description

Convert a string representing a number into an integer

Examples

This function is used in the following places in Espruino's documentation

function peek16

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Call type:

function peek16(addr, count)

Parameters

addr - The address in memory to read

count - (optional) the number of items to read. If >1 a Uint16Array will be returned.

Returns

The value of memory at the given location

Description

Read 16 bits of memory at the given location - DANGEROUS!

Examples

This function is used in the following places in Espruino's documentation

function peek32

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Call type:

function peek32(addr, count)

Parameters

addr - The address in memory to read

count - (optional) the number of items to read. If >1 a Uint32Array will be returned.

Returns

The value of memory at the given location

Description

Read 32 bits of memory at the given location - DANGEROUS!

Examples

This function is used in the following places in Espruino's documentation

function peek8

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Call type:

function peek8(addr, count)

Parameters

addr - The address in memory to read

count - (optional) the number of items to read. If >1 a Uint8Array will be returned.

Returns

The value of memory at the given location

Description

Read 8 bits of memory at the given location - DANGEROUS!

function pinMode

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Call type:

function pinMode(pin, mode, automatic)

Parameters

pin - The pin to set pin mode for

mode - The mode - a string that is either 'analog', 'input', 'input_pullup', 'input_pulldown', 'output', 'opendrain', 'af_output' or 'af_opendrain'. Do not include this argument or use 'auto' if you want to revert to automatic pin mode setting.

automatic - Optional, default is false. If true, subsequent commands will automatically change the state (see notes below)

Description

Set the mode of the given pin.

Note: digitalRead/digitalWrite/etc set the pin mode automatically unless pinMode has been called first. If you want digitalRead/etc to set the pin mode automatically after you have called pinMode, simply call it again with no mode argument (pinMode(pin)), auto as the argument (pinMode(pin, "auto")), or with the 3rd 'automatic' argument set to true (pinMode(pin, "output", true)).

Examples

This function is used in the following places in Espruino's documentation

function poke16

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Call type:

function poke16(addr, value)

Parameters

addr - The address in memory to write

value - The value to write, or an array of values

Description

Write 16 bits of memory at the given location - VERY DANGEROUS!

Examples

This function is used in the following places in Espruino's documentation

function poke32

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Call type:

function poke32(addr, value)

Parameters

addr - The address in memory to write

value - The value to write, or an array of values

Description

Write 32 bits of memory at the given location - VERY DANGEROUS!

Examples

This function is used in the following places in Espruino's documentation

function poke8

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Call type:

function poke8(addr, value)

Parameters

addr - The address in memory to write

value - The value to write, or an array of values

Description

Write 8 bits of memory at the given location - VERY DANGEROUS!

function print

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Call type:

function print(text, ...)

Parameters

text, ... -

Description

Print the supplied string(s) to the console

Note: If you're connected to a computer (not a wall adaptor) via USB but you are not running a terminal app then when you print data Espruino may pause execution and wait until the computer requests the data it is trying to print.

Examples

This function is used in the following places in Espruino's documentation

function require

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Call type:

function require(moduleName)

Parameters

moduleName - A String containing the name of the given module

Returns

The result of evaluating the string

Description

Load the given module, and return the exported functions and variables.

For example:

var s = require("Storage");
s.write("test", "hello world");
print(s.read("test"));
// prints "hello world"

Check out the page on Modules for an explanation of what modules are and how you can use them.

function reset

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Call type:

function reset(clearFlash)

Parameters

clearFlash - Remove saved code from flash as well

Description

Reset the interpreter - clear program memory in RAM, and do not load a saved program from flash. This does NOT reset the underlying hardware (which allows you to reset the device without it disconnecting from USB).

This command only executes when the Interpreter returns to the Idle state - for instance a=1;reset();a=2; will still leave 'a' as undefined.

The safest way to do a full reset is to hit the reset button.

If reset() is called with no arguments, it will reset the board's state in RAM but will not reset the state in flash. When next powered on (or when load() is called) the board will load the previously saved code.

Calling reset(true) will cause all saved code in flash memory to be cleared as well.

Examples

This function is used in the following places in Espruino's documentation

function save

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Call type:

function save()

Description

Save the state of the interpreter into flash (including the results of calling setWatch, setInterval, pinMode, and any listeners). The state will then be loaded automatically every time Espruino powers on or is hard-reset. To see what will get saved you can call dump().

Note: If you set up intervals/etc in onInit() and you have already called onInit before running save(), when Espruino resumes there will be two copies of your intervals - the ones from before the save, and the ones from after - which may cause you problems.

For more information about this and other options for saving, please see the Saving code on Espruino page.

This command only executes when the Interpreter returns to the Idle state - for instance a=1;save();a=2; will save 'a' as 2.

When Espruino powers on, it will resume from where it was when you typed save(). If you want code to be executed right after loading (for instance to initialise devices connected to Espruino), add a function called onInit, or add a init event handler to E with E.on('init', function() { ... your_code ... });. This will then be automatically executed by Espruino every time it starts.

In order to stop the program saved with this command being loaded automatically, check out the Troubleshooting guide

Serial1

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Instance of Serial

Description

The first Serial (USART) port

Note: This is only available in devices with more than 1 USART peripherals

function setBusyIndicator

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Call type:

function setBusyIndicator(pin)

Parameters

pin -

Description

When Espruino is busy, set the pin specified here high. Set this to undefined to disable the feature.

Note: This is not available in devices with low flash memory

function setInterval

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Call type:

function setInterval(function, timeout, args, ...)

Parameters

function - A Function or String to be executed

timeout - The time between calls to the function (max 3153600000000 = 100 years

args, ... - Optional arguments to pass to the function when executed

Returns

An ID that can be passed to clearInterval

Description

Call the function (or evaluate the string) specified REPEATEDLY after the timeout in milliseconds.

For instance:

setInterval(function () {
  console.log("Hello World");
}, 1000);
// or
setInterval('console.log("Hello World");', 1000);
// both print 'Hello World' every second

You can also specify extra arguments that will be sent to the function when it is executed. For example:

setInterval(function (a,b) {
  console.log(a+" "+b);
}, 1000, "Hello", "World");
// prints 'Hello World' every second

If you want to stop your function from being called, pass the number that was returned by setInterval into the clearInterval function.

Note: If setDeepSleep(true) has been called and the interval is greater than 5 seconds, Espruino may execute the interval up to 1 second late. This is because Espruino can only wake from deep sleep every second - and waking early would cause Espruino to waste power while it waited for the correct time.

function setSleepIndicator

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Call type:

function setSleepIndicator(pin)

Parameters

pin -

Description

When Espruino is asleep, set the pin specified here low (when it's awake, set it high). Set this to undefined to disable the feature.

Please see http://www.espruino.com/Power+Consumption for more details on this.

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

function setTime

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Call type:

function setTime(time)

Parameters

time -

Description

Set the current system time in seconds (to the nearest second).

This is used with getTime, the time reported from setWatch, as well as when using new Date().

Date.prototype.getTime() reports the time in milliseconds, so you can set the time to a Date object using:

setTime((new Date("Tue, 19 Feb 2019 10:57")).getTime()/1000)

To set the timezone for all new Dates, use E.setTimeZone(hours).

function setTimeout

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Call type:

function setTimeout(function, timeout, args, ...)

Parameters

function - A Function or String to be executed

timeout - The time until the function will be executed (max 3153600000000 = 100 years

args, ... - Optional arguments to pass to the function when executed

Returns

An ID that can be passed to clearTimeout

Description

Call the function (or evaluate the string) specified ONCE after the timeout in milliseconds.

For instance:

setTimeout(function () {
  console.log("Hello World");
}, 1000);
// or
setTimeout('console.log("Hello World");', 1000);
// both print 'Hello World' after a second

You can also specify extra arguments that will be sent to the function when it is executed. For example:

setTimeout(function (a,b) {
  console.log(a+" "+b);
}, 1000, "Hello", "World");
// prints 'Hello World' after 1 second

If you want to stop the function from being called, pass the number that was returned by setTimeout into the clearInterval function.

Note: If setDeepSleep(true) has been called and the interval is greater than 5 seconds, Espruino may execute the interval up to 1 second late. This is because Espruino can only wake from deep sleep every second - and waking early would cause Espruino to waste power while it waited for the correct time.

function setWatch

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Call type:

function setWatch(function, pin, options)

Parameters

function - A Function or String to be executed

pin - The pin to watch

options - If a boolean or integer, it determines whether to call this once (false = default) or every time a change occurs (true). Can be an object of the form { repeat: true/false(default), edge:'rising'/'falling'/'both'(default), debounce:10} - see below for more information.

Returns

An ID that can be passed to clearWatch

Description

Call the function specified when the pin changes. Watches set with setWatch can be removed using clearWatch.

If the options parameter is an object, it can contain the following information (all optional):

{
   // Whether to keep producing callbacks, or remove the watch after the first callback
   repeat: true/false(default),
   // Trigger on the rising or falling edge of the signal. Can be a string, or 1='rising', -1='falling', 0='both'
   edge:'rising'(default for built-in buttons)/'falling'/'both'(default for pins),
   // Use software-debouncing to stop multiple calls if a switch bounces
   // This is the time in milliseconds to wait for bounces to subside, or 0 to disable
   debounce:10 (0 is default for pins, 25 is default for built-in buttons),
   // Advanced: If the function supplied is a 'native' function (compiled or assembly)
   // setting irq:true will call that function in the interrupt itself
   irq : false(default)
   // Advanced: If specified, the given pin will be read whenever the watch is called
   // and the state will be included as a 'data' field in the callback
   data : pin
}

The function callback is called with an argument, which is an object of type {state:bool, time:float, lastTime:float}.

For instance, if you want to measure the length of a positive pulse you could use setWatch(function(e) { console.log(e.time-e.lastTime); }, BTN, { repeat:true, edge:'falling' });. This will only be called on the falling edge of the pulse, but will be able to measure the width of the pulse because e.lastTime is the time of the rising edge.

Internally, an interrupt writes the time of the pin's state change into a queue with the exact time that it happened, and the function supplied to setWatch is executed only from the main message loop. However, if the callback is a native function void (bool state) then you can add irq:true to options, which will cause the function to be called from within the IRQ. When doing this, interrupts will happen on both edges and there will be no debouncing.

Note: if you didn't call pinMode beforehand then this function will reset pin's state to "input"

Note: The STM32 chip (used in the Espruino Board and Pico) cannot watch two pins with the same number - eg A0 and B0.

Note: On nRF52 chips (used in Puck.js, Pixl.js, MDBT42Q) setWatch disables the GPIO output on that pin. In order to be able to write to the pin again you need to disable the watch with clearWatch.

function shiftOut

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Call type:

function shiftOut(pins, options, data)

Parameters

pins - A pin, or an array of pins to use

options - Options, for instance the clock (see below)

data - The data to shift out (see E.toUint8Array for info on the forms this can take)

Description

Shift an array of data out using the pins supplied least significant bit first, for example:

// shift out to single clk+data
shiftOut(A0, { clk : A1 }, [1,0,1,0]);

// shift out a whole byte (like software SPI)
shiftOut(A0, { clk : A1, repeat: 8 }, [1,2,3,4]);

// shift out via 4 data pins
shiftOut([A3,A2,A1,A0], { clk : A4 }, [1,2,3,4]);

options is an object of the form:

{
  clk : pin, // a pin to use as the clock (undefined = no pin)
  clkPol : bool, // clock polarity - default is 0 (so 1 normally, pulsing to 0 to clock data in)
  repeat : int, // number of clocks per array item
}

Each item in the data array will be output to the pins, with the first pin in the array being the MSB and the last the LSB, then the clock will be pulsed in the polarity given.

repeat is the amount of times shift data out for each array item. For instance we may want to shift 8 bits out through 2 pins - in which case we need to set repeat to 4.

SPI1

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Instance of SPI

Description

The first SPI port

Note: This is only available in devices with more than 1 SPI peripherals

Terminal

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Instance of Serial

Description

A simple VT100 terminal emulator.

When data is sent to the Terminal object, Graphics.getInstance() is called and if an instance of Graphics is found then characters are written to it.

Note: This is only available in devices with VT100 terminal emulation enabled (Pixl.js only)

function trace

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Call type:

function trace(root)

Parameters

root - The symbol to output (optional). If nothing is specified, everything will be output

Description

Output debugging information

Note: This is not included on boards with low amounts of flash memory, or the Espruino board.

Note: This is not available in devices with low flash memory

variable VIBRATE

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Call type:

variable VIBRATE

Returns

See description above

Description

The Bangle.js's vibration motor.

Note: This is only available in Bangle.js smartwatches

Array Class

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This is the built-in JavaScript class for arrays.

Arrays can be defined with [], new Array(), or new Array(length)

Methods and Fields

constructor Array

View MDN documentation

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Call type:

new Array(args, ...)

Parameters

args, ... - The length of the array OR any number of items to add to the array

Returns

An Array

Description

Create an Array. Either give it one integer argument (>=0) which is the length of the array, or any number of arguments

function Array.concat

View MDN documentation

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Call type:

function Array.concat(args, ...)

Parameters

args, ... - Any items to add to the array

Returns

An Array

Description

Create a new array, containing the elements from this one and any arguments, if any argument is an array then those elements will be added.

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

function Array.every

View MDN documentation

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Call type:

function Array.every(function, thisArg)

Parameters

function - Function to be executed

thisArg - if specified, the function is called with 'this' set to thisArg (optional)

Returns

A boolean containing the result

Description

Return 'true' if the callback returns 'true' for every element in the array

function Array.fill

View MDN documentation

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Call type:

function Array.fill(value, start, end)

Parameters

value - The value to fill the array with

start - Optional. The index to start from (or 0). If start is negative, it is treated as length+start where length is the length of the array

end - Optional. The index to end at (or the array length). If end is negative, it is treated as length+end.

Returns

This array

Description

Fill this array with the given value, for every index >= start and < end

Note: This is not available in devices with low flash memory

function Array.filter

View MDN documentation

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Call type:

function Array.filter(function, thisArg)

Parameters

function - Function to be executed

thisArg - if specified, the function is called with 'this' set to thisArg (optional)

Returns

An array containing the results

Description

Return an array which contains only those elements for which the callback function returns 'true'

function Array.find

View MDN documentation

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Call type:

function Array.find(function)

Parameters

function - Function to be executed

Returns

The array element where function returns true, or undefined

Description

Return the array element where function returns true, or undefined if it doesn't returns true for any element.

["Hello","There","World"].find(a=>a[0]=="T")
// returns "There"

Note: This is not available in devices with low flash memory

function Array.findIndex

View MDN documentation

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Call type:

function Array.findIndex(function)

Parameters

function - Function to be executed

Returns

The array element's index where function returns true, or -1

Description

Return the array element's index where function returns true, or -1 if it doesn't returns true for any element.

["Hello","There","World"].findIndex(a=>a[0]=="T")
// returns 1

Note: This is not available in devices with low flash memory

function Array.forEach

View MDN documentation

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Call type:

function Array.forEach(function, thisArg)

Parameters

function - Function to be executed

thisArg - if specified, the function is called with 'this' set to thisArg (optional)

Description

Executes a provided function once per array element.

function Array.includes

View MDN documentation

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Call type:

function Array.includes(value, startIndex)

Parameters

value - The value to check for

startIndex - (optional) the index to search from, or 0 if not specified

Returns

true if the array includes the value, false otherwise

Description

Return true if the array includes the value, false otherwise

Note: This is not available in devices with low flash memory

function Array.indexOf

View MDN documentation

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Call type:

function Array.indexOf(value, startIndex)

Parameters

value - The value to check for

startIndex - (optional) the index to search from, or 0 if not specified

Returns

the index of the value in the array, or -1

Description

Return the index of the value in the array, or -1

Examples

This function is used in the following places in Espruino's documentation

Array.isArray

View MDN documentation

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Call type:

Array.isArray(var)

Parameters

var - The variable to be tested

Returns

True if var is an array, false if not.

Description

Returns true if the provided object is an array

function Array.join

View MDN documentation

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Call type:

function Array.join(separator)

Parameters

separator - The separator

Returns

A String representing the Joined array

Description

Join all elements of this array together into one string, using 'separator' between them. eg. [1,2,3].join(' ')=='1 2 3'

property Array.length

View MDN documentation

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Call type:

property Array.length

Returns

The value of the array

Description

Find the length of the array

function Array.map

View MDN documentation

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Call type:

function Array.map(function, thisArg)

Parameters

function - Function used to map one item to another

thisArg - if specified, the function is called with 'this' set to thisArg (optional)

Returns

An array containing the results

Description

Return an array which is made from the following: A.map(function) = [function(A[0]), function(A[1]), ...]

function Array.pop

View MDN documentation

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Call type:

function Array.pop()

Returns

The value that is popped off

Description

Remove and return the value on the end of this array.

This is the opposite of [1,2,3].shift(), which removes an element from the beginning of the array.

function Array.push

View MDN documentation

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Call type:

function Array.push(arguments, ...)

Parameters

arguments, ... - One or more arguments to add

Returns

The new size of the array

Description

Push a new value onto the end of this array'

This is the opposite of [1,2,3].unshift(0), which adds one or more elements to the beginning of the array.

Examples

This function is used in the following places in Espruino's documentation

function Array.reduce

View MDN documentation

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Call type:

function Array.reduce(callback, initialValue)

Parameters

callback - Function used to reduce the array

initialValue - if specified, the initial value to pass to the function

Returns

The value returned by the last function called

Description

Execute previousValue=initialValue and then previousValue = callback(previousValue, currentValue, index, array) for each element in the array, and finally return previousValue.

Note: This is not available in devices with low flash memory

function Array.reverse

View MDN documentation

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Call type:

function Array.reverse()

Returns

The array, but reversed.

Description

Reverse all elements in this array (in place)

Note: This is not available in devices with low flash memory

function Array.shift

View MDN documentation

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Call type:

function Array.shift()

Parameters

Returns

The element that was removed

Description

Remove and return the first element of the array.

This is the opposite of [1,2,3].pop(), which takes an element off the end.

Note: This is not available in devices with low flash memory

function Array.slice

View MDN documentation

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Call type:

function Array.slice(start, end)

Parameters

start - Start index

end - End index (optional)

Returns

A new array

Description

Return a copy of a portion of this array (in a new array)

function Array.some

View MDN documentation

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Call type:

function Array.some(function, thisArg)

Parameters

function - Function to be executed

thisArg - if specified, the function is called with 'this' set to thisArg (optional)

Returns

A boolean containing the result

Description

Return 'true' if the callback returns 'true' for any of the elements in the array

function Array.sort

View MDN documentation

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Call type:

function Array.sort(var)

Parameters

var - A function to use to compare array elements (or undefined)

Returns

This array object

Description

Do an in-place quicksort of the array

Note: This is not available in devices with low flash memory

function Array.splice

View MDN documentation

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Call type:

function Array.splice(index, howMany, elements, ...)

Parameters

index - Index at which to start changing the array. If negative, will begin that many elements from the end

howMany - An integer indicating the number of old array elements to remove. If howMany is 0, no elements are removed.

elements, ... - One or more items to add to the array

Returns

An array containing the removed elements. If only one element is removed, an array of one element is returned.

Description

Both remove and add items to an array

function Array.toString

View MDN documentation

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Call type:

function Array.toString(radix)

Parameters

radix - unused

Returns

A String representing the array

Description

Convert the Array to a string

function Array.unshift

View MDN documentation

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Call type:

function Array.unshift(elements, ...)

Parameters

elements, ... - One or more items to add to the beginning of the array

Returns

The new array length

Description

Add one or more items to the start of the array, and return its new length.

This is the opposite of [1,2,3].push(4), which puts one or more elements on the end.

Note: This is not available in devices with low flash memory

ArrayBuffer Class

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This is the built-in JavaScript class for array buffers.

If you want to access arrays of differing types of data you may also find DataView useful.

Methods and Fields

constructor ArrayBuffer

View MDN documentation

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Call type:

new ArrayBuffer(byteLength)

Parameters

byteLength - The length in Bytes

Returns

An ArrayBuffer object

Description

Create an Array Buffer object

property ArrayBuffer.byteLength

View MDN documentation

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Call type:

property ArrayBuffer.byteLength

Returns

The Length in bytes

Description

The length, in bytes, of the ArrayBuffer

ArrayBufferView Class

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This is the built-in JavaScript class that is the prototype for:

If you want to access arrays of differing types of data you may also find DataView useful.

Methods and Fields

property ArrayBufferView.buffer

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Call type:

property ArrayBufferView.buffer

Returns

An ArrayBuffer object

Description

The buffer this view references

property ArrayBufferView.byteLength

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Call type:

property ArrayBufferView.byteLength

Returns

The Length

Description

The length, in bytes, of the ArrayBufferView

property ArrayBufferView.byteOffset

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Call type:

property ArrayBufferView.byteOffset

Returns

The byte Offset

Description

The offset, in bytes, to the first byte of the view within the backing ArrayBuffer

function ArrayBufferView.fill

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Call type:

function ArrayBufferView.fill(value, start, end)

Parameters

value - The value to fill the array with

start - Optional. The index to start from (or 0). If start is negative, it is treated as length+start where length is the length of the array

end - Optional. The index to end at (or the array length). If end is negative, it is treated as length+end.

Returns

This array

Description

Fill this array with the given value, for every index >= start and < end

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

function ArrayBufferView.filter

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Call type:

function ArrayBufferView.filter(function, thisArg)

Parameters

function - Function to be executed

thisArg - if specified, the function is called with 'this' set to thisArg (optional)

Returns

An array containing the results

Description

Return an array which contains only those elements for which the callback function returns 'true'

Note: This is not available in devices with low flash memory

function ArrayBufferView.find

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Call type:

function ArrayBufferView.find(function)

Parameters

function - Function to be executed

Returns

The array element where function returns true, or undefined

Description

Return the array element where function returns true, or undefined if it doesn't returns true for any element.

Note: This is not available in devices with low flash memory

function ArrayBufferView.findIndex

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Call type:

function ArrayBufferView.findIndex(function)

Parameters

function - Function to be executed

Returns

The array element's index where function returns true, or -1

Description

Return the array element's index where function returns true, or -1 if it doesn't returns true for any element.

Note: This is not available in devices with low flash memory

function ArrayBufferView.forEach

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Call type:

function ArrayBufferView.forEach(function, thisArg)

Parameters

function - Function to be executed

thisArg - if specified, the function is called with 'this' set to thisArg (optional)

Description

Executes a provided function once per array element.

function ArrayBufferView.includes

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Call type:

function ArrayBufferView.includes(value, startIndex)

Parameters

value - The value to check for

startIndex - (optional) the index to search from, or 0 if not specified

Returns

true if the array includes the value, false otherwise

Description

Return true if the array includes the value, false otherwise

Note: This is not available in devices with low flash memory

function ArrayBufferView.indexOf

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Call type:

function ArrayBufferView.indexOf(value, startIndex)

Parameters

value - The value to check for

startIndex - (optional) the index to search from, or 0 if not specified

Returns

the index of the value in the array, or -1

Description

Return the index of the value in the array, or -1

function ArrayBufferView.join

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Call type:

function ArrayBufferView.join(separator)

Parameters

separator - The separator

Returns

A String representing the Joined array

Description

Join all elements of this array together into one string, using 'separator' between them. eg. [1,2,3].join(' ')=='1 2 3'

function ArrayBufferView.map

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Call type:

function ArrayBufferView.map(function, thisArg)

Parameters

function - Function used to map one item to another

thisArg - if specified, the function is called with 'this' set to thisArg (optional)

Returns

An array containing the results

Description

Return an array which is made from the following: A.map(function) = [function(A[0]), function(A[1]), ...]

Note: This returns an ArrayBuffer of the same type it was called on. To get an Array, use Array.map, eg. [].map.call(myArray, x=>x+1)

function ArrayBufferView.reduce

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Call type:

function ArrayBufferView.reduce(callback, initialValue)

Parameters

callback - Function used to reduce the array

initialValue - if specified, the initial value to pass to the function

Returns

The value returned by the last function called

Description

Execute previousValue=initialValue and then previousValue = callback(previousValue, currentValue, index, array) for each element in the array, and finally return previousValue.

Note: This is not available in devices with low flash memory

function ArrayBufferView.reverse

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Call type:

function ArrayBufferView.reverse()

Returns

This array

Description

Reverse the contents of this ArrayBufferView in-place

Note: This is not available in devices with low flash memory

function ArrayBufferView.set

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Call type:

function ArrayBufferView.set(arr, offset)

Parameters

arr - Floating point index to access

offset - The offset in this array at which to write the values (optional)

Description

Copy the contents of array into this one, mapping this[x+offset]=array[x];

Examples

This function is used in the following places in Espruino's documentation

function ArrayBufferView.slice

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Call type:

function ArrayBufferView.slice(start, end)

Parameters

start - Start index

end - End index (optional)

Returns

A new array

Description

Return a copy of a portion of this array (in a new array).

Note: This currently returns a normal Array, not an ArrayBuffer

Note: This is not available in devices with low flash memory

function ArrayBufferView.sort

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Call type:

function ArrayBufferView.sort(var)

Parameters

var - A function to use to compare array elements (or undefined)

Returns

This array object

Description

Do an in-place quicksort of the array

Note: This is not available in devices with low flash memory

Bangle Class

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Class containing utility functions for the Bangle.js Smart Watch

Methods and Fields

event Bangle.accel

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Call type:

Bangle.on('accel', function(xyz) { ... });

Parameters

xyz -

Description

Accelerometer data available with {x,y,z,diff,mag} object as a parameter.

You can also retrieve the most recent reading with Bangle.getAccel().

Note: This is only available in Bangle.js smartwatches

Bangle.accelRd

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Call type:

Bangle.accelRd(reg)

Parameters

reg -

Returns

See description above

Description

Reads a register from the KX023 Accelerometer

Note: This is only available in Bangle.js smartwatches

Bangle.accelWr

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Call type:

Bangle.accelWr(reg, data)

Parameters

reg -

data -

Description

Writes a register on the KX023 Accelerometer

Note: This is only available in Bangle.js smartwatches

event Bangle.aiGesture

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Call type:

Bangle.on('aiGesture', function(gesture, weights) { ... });

Parameters

gesture - The name of the gesture (if '.tfnames' exists, or the index. 'undefined' if not matching

weights - An array of floating point values output by the model

Description

Emitted when a 'gesture' (fast movement) is detected, and a Tensorflow model is in storage in the ".tfmodel" file.

If a ".tfnames" file is specified as a comma-separated list of names, it will be used to decode gesture from a number into a string.

Note: This is only available in Bangle.js smartwatches

Bangle.beep

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Call type:

Bangle.beep(time, freq)

Parameters

time - Time in ms (default 200)

freq - Frequency in hz (default 4000)

Returns

A promise, completed when beep is finished

Description

Use the piezo speaker to Beep for a certain time period and frequency

Note: This is only available in Bangle.js smartwatches

Examples

This function is used in the following places in Espruino's documentation

Bangle.buzz

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Call type:

Bangle.buzz(time, strength)

Parameters

time - Time in ms (default 200)

strength - Power of vibration from 0 to 1 (Default 1)

Returns

A promise, completed when vibration is finished

Description

Use the vibration motor to buzz for a certain time period

Note: This is only available in Bangle.js smartwatches

Examples

This function is used in the following places in Espruino's documentation

event Bangle.charging

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Call type:

Bangle.on('charging', function(charging) { ... });

Parameters

charging - true if charging

Description

Is the battery charging or not?

Note: This is only available in Bangle.js smartwatches

Bangle.compassWr

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Call type:

Bangle.compassWr(reg, data)

Parameters

reg -

data -

Description

Writes a register on the Magnetometer/Compass

Note: This is only available in Bangle.js smartwatches

Bangle.dbg

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Call type:

Bangle.dbg()

Returns

See description above

Description

Reads debug info

Note: This is only available in Bangle.js smartwatches

Bangle.drawWidgets

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Call type:

Bangle.drawWidgets()

Description

Draw any onscreen widgets that were loaded with Bangle.loadWidgets().

Widgets should redraw themselves when something changes - you'll only need to call drawWidgets if you decide to clear the entire screen with g.clear().

Note: This is only available in Bangle.js smartwatches

event Bangle.faceUp

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Call type:

Bangle.on('faceUp', function(up) { ... });

Parameters

up - true if face-up

Description

Has the watch been moved so that it is face-up, or not face up?

Note: This is only available in Bangle.js smartwatches

event Bangle.gesture

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Call type:

Bangle.on('gesture', function(xyz) { ... });

Parameters

xyz - An Int8Array of XYZXYZXYZ data

Description

Emitted when a 'gesture' (fast movement) is detected

Note: This is only available in Bangle.js smartwatches

Bangle.getAccel

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Call type:

Bangle.getAccel()

Returns

An object containing accelerometer readings (as below)

Description

Get the most recent accelerometer reading. Data is in the same format as the Bangle.on('accel', event.

Note: This is only available in Bangle.js smartwatches

Bangle.getCompass

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Call type:

Bangle.getCompass()

Returns

An object containing magnetometer readings (as below)

Description

Get the most recent Magnetometer/Compass reading. Data is in the same format as the Bangle.on('mag', event.

Returns an {x,y,z,dx,dy,dz,heading} object

To get this event you must turn the compass on with Bangle.setCompassPower(1).

Note: This is only available in Bangle.js smartwatches

Bangle.getLCDMode

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Call type:

Bangle.getLCDMode()

Returns

The LCD mode as a String

Description

The current LCD mode.

See Bangle.setLCDMode for examples.

Note: This is only available in Bangle.js smartwatches

Bangle.getLogo

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Call type:

Bangle.getLogo()

Returns

An image to be used with g.drawImage - 222 x 104 x 2 bits

event Bangle.GPS

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Call type:

Bangle.on('GPS', function(fix) { ... });

Parameters

fix - An object with fix info (see below)

Description

GPS data, as an object. Contains:

{ "lat": number,      // Latitude in degrees
  "lon": number,      // Longitude in degrees
  "alt": number,      // altitude in M
  "speed": number,    // Speed in kph
  "course": number,   // Course in degrees
  "time": Date,       // Current Time (or undefined if not known)
  "satellites": 7,    // Number of satellites
  "fix": 1            // NMEA Fix state - 0 is no fix
}

If a value such as lat is not known because there is no fix, it'll be NaN.

To get this event you must turn the GPS on with Bangle.setGPSPower(1).

Note: This is only available in Bangle.js smartwatches

event Bangle.GPS-raw

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Call type:

Bangle.on('GPS-raw', function(nmea) { ... });

Parameters

nmea -

Description

Raw NMEA GPS data lines received as a string

To get this event you must turn the GPS on with Bangle.setGPSPower(1).

Note: This is only available in Bangle.js smartwatches

event Bangle.HRM

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Call type:

Bangle.on('HRM', function(hrm) { ... });

Parameters

hrm - An object with heart rate info (see below)

Description

Heat rate data, as an object. Contains:

{ "bpm": number,             // Beats per minute
  "confidence": number,      // 0-100 percentage confidence in the heart rate
  "raw": Uint8Array,         // raw samples from heart rate monitor
}

To get this event you must turn the heart rate monitor on with Bangle.setHRMPower(1).

Note: This is only available in Bangle.js smartwatches

Bangle.ioWr

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Call type:

Bangle.ioWr(mask, isOn)

Parameters

mask -

isOn -

Description

Changes a pin state on the IO expander

Note: This is only available in Bangle.js smartwatches

Examples

This function is used in the following places in Espruino's documentation

Bangle.isCharging

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Call type:

Bangle.isCharging()

Returns

Is the battery charging or not?

Bangle.isLCDOn

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Call type:

Bangle.isLCDOn()

Returns

Is the display on or not?

event Bangle.lcdPower

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Call type:

Bangle.on('lcdPower', function(on) { ... });

Parameters

on - true if screen is on

Description

Has the screen been turned on or off? Can be used to stop tasks that are no longer useful if nothing is displayed.

Note: This is only available in Bangle.js smartwatches

Bangle.lcdWr

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Call type:

Bangle.lcdWr(cmd, data)

Parameters

cmd -

data -

Description

Writes a command directly to the ST7735 LCD controller

Note: This is only available in Bangle.js smartwatches

Bangle.loadWidgets

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Call type:

Bangle.loadWidgets()

Description

Load all widgets from flash Storage. Call this once at the beginning of your application if you want any on-screen widgets to be loaded.

They will be loaded into a global WIDGETS array, and can be rendered with Bangle.drawWidgets.

Note: This is only available in Bangle.js smartwatches

event Bangle.mag

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Call type:

Bangle.on('mag', function(xyz) { ... });

Parameters

xyz -

Description

Magnetometer/Compass data available with {x,y,z,dx,dy,dz,heading} object as a parameter

To get this event you must turn the compass on with Bangle.setCompassPower(1).

You can also retrieve the most recent reading with Bangle.getCompass().

Note: This is only available in Bangle.js smartwatches

Bangle.off

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Call type:

Bangle.off()

Description

Turn Bangle.js off. It can only be woken by pressing BTN1.

Note: This is only available in Bangle.js smartwatches

Bangle.project

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Call type:

Bangle.project(latlong)

Parameters

latlong - {lat:..., lon:...}

Returns

{x:..., y:...}

Description

Perform a Spherical Web Mercator projection of latitude and longitude into x and y coordinates, which are roughly equivalent to meters from {lat:0,lon:0}.

This is the formula used for most online mapping and is a good way to compare GPS coordinates to work out the distance between them.

Note: This is only available in Bangle.js smartwatches

Bangle.setCompassPower

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Call type:

Bangle.setCompassPower(isOn)

Parameters

isOn - True if the Compass should be on, false if not

Description

Set the power to the Compass

When on, data is output via the mag event on Bangle:

Bangle.setCompassPower(1);
Bangle.on('mag',print);

When on, the compass draws roughly 2mA

Note: This is only available in Bangle.js smartwatches

Bangle.setGPSPower

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Call type:

Bangle.setGPSPower(isOn)

Parameters

isOn - True if the GPS should be on, false if not

Description

Set the power to the GPS.

When on, data is output via the GPS event on Bangle:

Bangle.setGPSPower(1);
Bangle.on('GPS',print);

When on, the GPS draws roughly 20mA

Note: This is only available in Bangle.js smartwatches

Bangle.setHRMPower

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Call type:

Bangle.setHRMPower(isOn)

Parameters

isOn - True if the heart rate monitor should be on, false if not

Description

Set the power to the Heart rate monitor

When on, data is output via the GPS event on Bangle:

Bangle.setHRMPower(1);
Bangle.on('HRM',print);

When on, the Heart rate monitor draws roughly 5mA

Note: This is only available in Bangle.js smartwatches

Bangle.setLCDBrightness

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Call type:

Bangle.setLCDBrightness(brightness)

Parameters

brightness - The brightness of Bangle.js's display - from 0(off) to 1(on full)

Description

This function can be used to adjust the brightness of Bangle.js's display, and hence prolong its battery life.

Due to hardware design constraints, software PWM has to be used which means that the display may flicker slightly when Bluetooth is active and the display is not at full power.

Power consumption

Note: This is only available in Bangle.js smartwatches

Bangle.setLCDMode

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Call type:

Bangle.setLCDMode(mode)

Parameters

mode - The LCD mode (See below)

Description

This function can be used to change the way graphics is handled on Bangle.js.

Available options for Bangle.setLCDMode are:

You can also call Bangle.setLCDMode() to return to normal, unbuffered "direct" mode.

Note: This is only available in Bangle.js smartwatches

Bangle.setLCDOffset

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Call type:

Bangle.setLCDOffset(y)

Parameters

y - The amount of pixels to shift the LCD up or down

Description

This can be used to move the displayed memory area up or down temporarily. It's used for displaying notifications while keeping the main display contents intact.

Note: This is only available in Bangle.js smartwatches

Bangle.setLCDPower

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Call type:

Bangle.setLCDPower(isOn)

Parameters

isOn - True if the LCD should be on, false if not

Description

This function can be used to turn Bangle.js's LCD off or on.

When on full, the LCD draws roughly 40mA. You can adjust When brightness using Bange.setLCDBrightness.

Note: This is only available in Bangle.js smartwatches

Bangle.setLCDTimeout

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Call type:

Bangle.setLCDTimeout(isOn)

Parameters

isOn - The timeout of the display in seconds, or 0/undefined to turn power saving off. Default is 10 seconds.

Description

This function can be used to turn Bangle.js's LCD power saving on or off.

With power saving off, the display will remain in the state you set it with Bangle.setLCDPower.

With power saving on, the display will turn on if a button is pressed, the watch is turned face up, or the screen is updated. It'll turn off automatically after the given timeout.

Note: This is only available in Bangle.js smartwatches

Bangle.setOptions

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Call type:

Bangle.setOptions(options)

Parameters

options -

Description

Set internal options used for gestures, step counting, etc...

Where accelerations are used they are in internal units, where 8192 = 1g

Note: This is only available in Bangle.js smartwatches

Bangle.setPollInterval

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Call type:

Bangle.setPollInterval(interval)

Parameters

interval - Polling interval in milliseconds

Description

Set how often the watch should poll for new acceleration/gyro data

Note: This is only available in Bangle.js smartwatches

Bangle.showLauncher

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Call type:

Bangle.showLauncher()

Description

Load the Bangle.js app launcher, which will allow the user to select an application to launch.

Note: This is only available in Bangle.js smartwatches

event Bangle.step

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Call type:

Bangle.on('step', function(up) { ... });

Parameters

up - The number of steps since Bangle.js was last reset

Description

Called whenever a step is detected by Bangle.js's pedometer.

Note: This is only available in Bangle.js smartwatches

event Bangle.swipe

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Call type:

Bangle.on('swipe', function(direction) { ... });

Parameters

direction - -1 for left, 1 for right

Description

Emitted when a swipe on the touchscreen is detected (a movement from left->right, or right->left)

Note: This is only available in Bangle.js smartwatches

event Bangle.touch

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Call type:

Bangle.on('touch', function(button) { ... });

Parameters

button - 1 for left, 2 for right

Description

Emitted when the touchscreen is pressed, either on the left or right hand side.

Note: This is only available in Bangle.js smartwatches

event Bangle.twist

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Call type:

Bangle.on('twist', function() { ... });

Description

This event happens when the watch has been twisted around it's axis - for instance as if it was rotated so someone could look at the time.

To tweak when this happens, see the twist* options in Bangle.setOptions()

Note: This is only available in Bangle.js smartwatches

BluetoothDevice Class

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A Web Bluetooth-style device - you can request one using NRF.requestDevice(address)

For example:

var gatt;
NRF.requestDevice({ filters: [{ name: 'Puck.js abcd' }] }).then(function(device) {
  console.log("found device");
  return device.gatt.connect();
}).then(function(g) {
  gatt = g;
  console.log("connected");
  return gatt.startBonding();
}).then(function() {
  console.log("bonded", gatt.getSecurityStatus());
  gatt.disconnect();
}).catch(function(e) {
  console.log("ERROR",e);
});

Methods and Fields

property BluetoothDevice.connected

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Call type:

property BluetoothDevice.connected

Returns

Whether the device is connected or not

property BluetoothDevice.gatt

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Call type:

property BluetoothDevice.gatt

Returns

A BluetoothRemoteGATTServer for this device

event BluetoothDevice.gattserverdisconnected

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Call type:

BluetoothDevice.on('gattserverdisconnected', function(reason) { ... });

Parameters

reason - The reason code reported back by the BLE stack - see Nordic's ble_hci.h file for more information

Description

Called when the device gets disconnected.

To connect and then print Disconnected when the device is disconnected, just do the following:

var gatt;
NRF.connect("aa:bb:cc:dd:ee:ff").then(function(gatt) {
  gatt.device.on('gattserverdisconnected', function(reason) {
    console.log("Disconnected ",reason);
  });
});

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

event BluetoothDevice.passkey

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Call type:

BluetoothDevice.on('passkey', function(passkey) { ... });

Parameters

passkey - A 6 character numeric String to be displayed

Description

Called when the device pairs and sends a passkey that Espruino should display.

For this to be used, you'll have to specify that there's a display using NRF.setSecurity

This is not part of the Web Bluetooth Specification. It has been added specifically for Espruino.

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

event BluetoothDevice.passkeyRequest

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Call type:

BluetoothDevice.on('passkeyRequest', function() { ... });

Description

Called when the device pairs, displays a passkey, and wants Espruino to tell it what the passkey was.

Respond with BluetoothDevice.sendPasskey() with a 6 character string containing only 0..9.

For this to be used, you'll have to specify that there's a keyboard using NRF.setSecurity

This is not part of the Web Bluetooth Specification. It has been added specifically for Espruino.

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

property BluetoothDevice.rssi

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Call type:

property BluetoothDevice.rssi

Returns

The last received RSSI (signal strength) for this device

function BluetoothDevice.sendPasskey

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Call type:

function BluetoothDevice.sendPasskey(passkey)

Parameters

passkey - A 6 character numeric String to be returned to the device

Description

To be used as a response when the event BluetoothDevice.sendPasskey has been received.

This is not part of the Web Bluetooth Specification. It has been added specifically for Espruino.

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

BluetoothRemoteGATTCharacteristic Class

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Web Bluetooth-style GATT characteristic - get this using BluetoothRemoteGATTService.getCharacteristic(s)

https://webbluetoothcg.github.io/web-bluetooth/#bluetoothremotegattcharacteristic

Methods and Fields

event BluetoothRemoteGATTCharacteristic.characteristicvaluechanged

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Call type:

BluetoothRemoteGATTCharacteristic.on('characteristicvaluechanged', function() { ... });

Description

Called when a characteristic's value changes, after BluetoothRemoteGATTCharacteristic.startNotifications has been called.

...
  return service.getCharacteristic("characteristic_uuid");
}).then(function(c) {
  c.on('characteristicvaluechanged', function(event) {
    console.log("-> "+event.target.value);
  });
  return c.startNotifications();
}).then(...

The first argument is of the form {target : BluetoothRemoteGATTCharacteristic}, and BluetoothRemoteGATTCharacteristic.value will then contain the new value (as a DataView).

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

function BluetoothRemoteGATTCharacteristic.readValue

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Call type:

function BluetoothRemoteGATTCharacteristic.readValue()

Returns

A Promise that is resolved (or rejected) with a DataView when the characteristic is read

Description

Read a characteristic's value, return a promise containing a DataView

var device;
NRF.connect(device_address).then(function(d) {
  device = d;
  return d.getPrimaryService("service_uuid");
}).then(function(s) {
  console.log("Service ",s);
  return s.getCharacteristic("characteristic_uuid");
}).then(function(c) {
  return c.readValue();
}).then(function(d) {
  console.log("Got:", JSON.stringify(d.buffer));
  device.disconnect();
}).catch(function() {
  console.log("Something's broken.");
});

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q) and ESP32 boards

function BluetoothRemoteGATTCharacteristic.startNotifications

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Call type:

function BluetoothRemoteGATTCharacteristic.startNotifications()

Returns

A Promise that is resolved (or rejected) with data when notifications have been added

Description

Starts notifications - whenever this characteristic's value changes, a characteristicvaluechanged event is fired and characteristic.value will then contain the new value as a DataView.

var device;
NRF.connect(device_address).then(function(d) {
  device = d;
  return d.getPrimaryService("service_uuid");
}).then(function(s) {
  console.log("Service ",s);
  return s.getCharacteristic("characteristic_uuid");
}).then(function(c) {
  c.on('characteristicvaluechanged', function(event) {
    console.log("-> "+event.target.value);
  });
  return c.startNotifications();
}).then(function(d) {
  console.log("Waiting for notifications");
}).catch(function() {
  console.log("Something's broken.");
});

For example, to listen to the output of another Puck.js's Nordic Serial port service, you can use:

var gatt;
NRF.connect("pu:ck:js:ad:dr:es random").then(function(g) {
  gatt = g;
  return gatt.getPrimaryService("6e400001-b5a3-f393-e0a9-e50e24dcca9e");
}).then(function(service) {
  return service.getCharacteristic("6e400003-b5a3-f393-e0a9-e50e24dcca9e");
}).then(function(characteristic) {
  characteristic.on('characteristicvaluechanged', function(event) {
    console.log("RX: "+JSON.stringify(event.target.value.buffer));
  });
  return characteristic.startNotifications();
}).then(function() {
  console.log("Done!");
});

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

function BluetoothRemoteGATTCharacteristic.stopNotifications

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Call type:

function BluetoothRemoteGATTCharacteristic.stopNotifications()

Returns

A Promise that is resolved (or rejected) with data when notifications have been removed

Description

Stop notifications (that were requested with BluetoothRemoteGATTCharacteristic.startNotifications)

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

function BluetoothRemoteGATTCharacteristic.writeValue

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Call type:

function BluetoothRemoteGATTCharacteristic.writeValue(data)

Parameters

data - The data to write

Returns

A Promise that is resolved (or rejected) when the characteristic is written

Description

Write a characteristic's value

var device;
NRF.connect(device_address).then(function(d) {
  device = d;
  return d.getPrimaryService("service_uuid");
}).then(function(s) {
  console.log("Service ",s);
  return s.getCharacteristic("characteristic_uuid");
}).then(function(c) {
  return c.writeValue("Hello");
}).then(function(d) {
  device.disconnect();
}).catch(function() {
  console.log("Something's broken.");
});

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q) and ESP32 boards

BluetoothRemoteGATTServer Class

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Web Bluetooth-style GATT server - get this using NRF.connect(address) or NRF.requestDevice(options) and response.gatt.connect

https://webbluetoothcg.github.io/web-bluetooth/#bluetoothremotegattserver

Methods and Fields

function BluetoothRemoteGATTServer.connect

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Call type:

function BluetoothRemoteGATTServer.connect(options)

Parameters

options - (Espruino-specific) An object of connection options (see below)

Returns

A Promise that is resolved (or rejected) when the connection is complete

Description

Connect to a BLE device - returns a promise, the argument of which is the BluetoothRemoteGATTServer connection.

See NRF.requestDevice for usage examples.

options is an optional object containing:

{
   minInterval // min connection interval in milliseconds, 7.5 ms to 4 s
   maxInterval // max connection interval in milliseconds, 7.5 ms to 4 s
}

By default the interval is 20-200ms (or 500-1000ms if NRF.setLowPowerConnection(true) was called. During connection Espruino negotiates with the other device to find a common interval that can be used.

For instance calling:

NRF.requestDevice({ filters: [{ namePrefix: 'Pixl.js' }] }).then(function(device) {
  return device.gatt.connect({minInterval:7.5, maxInterval:7.5});
}).then(function(g) {

will force the connection to use the fastest connection interval possible (as long as the device at the other end supports it).

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q) and ESP32 boards

function BluetoothRemoteGATTServer.disconnect

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Call type:

function BluetoothRemoteGATTServer.disconnect()

Returns

A Promise that is resolved (or rejected) when the disconnection is complete (non-standard)

Description

Disconnect from a previously connected BLE device connected with BluetoothRemoteGATTServer.connect - this does not disconnect from something that has connected to the Espruino.

Note: While .disconnect is standard Web Bluetooth, in the spec it returns undefined not a Promise for implementation reasons. In Espruino we return a Promise to make it easier to detect when Espruino is free to connect to something else.

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q) and ESP32 boards

function BluetoothRemoteGATTServer.getPrimaryService

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Call type:

function BluetoothRemoteGATTServer.getPrimaryService(service)

Parameters

service - The service UUID

Returns

A Promise that is resolved (or rejected) when the primary service is found (the argument contains a BluetoothRemoteGATTService)

Description

See NRF.connect for usage examples.

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q) and ESP32 boards

function BluetoothRemoteGATTServer.getPrimaryServices

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Call type:

function BluetoothRemoteGATTServer.getPrimaryServices()

Returns

A Promise that is resolved (or rejected) when the primary services are found (the argument contains an array of BluetoothRemoteGATTService)

function BluetoothRemoteGATTServer.getSecurityStatus

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Call type:

function BluetoothRemoteGATTServer.getSecurityStatus()

Returns

An object

Description

Return an object with information about the security state of the current connection:

{
  connected       // The connection is active (not disconnected).
  encrypted       // Communication on this link is encrypted.
  mitm_protected  // The encrypted communication is also protected against man-in-the-middle attacks.
  bonded          // The peer is bonded with us
}

See BluetoothRemoteGATTServer.startBonding for information about negotiating a secure connection.

This is not part of the Web Bluetooth Specification. It has been added specifically for Puck.js.

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

function BluetoothRemoteGATTServer.setRSSIHandler

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Call type:

function BluetoothRemoteGATTServer.setRSSIHandler(callback)

Parameters

callback - The callback to call with the RSSI value, or undefined to stop

Description

Start/stop listening for RSSI values on the active GATT connection

// Start listening for RSSI value updates
gattServer.setRSSIHandler(function(rssi) {
  console.log(rssi); // prints -85 (or similar)
});
// Stop listening
gattServer.setRSSIHandler();

RSSI is the 'Received Signal Strength Indication' in dBm

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q) and ESP32 boards

function BluetoothRemoteGATTServer.startBonding

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Call type:

function BluetoothRemoteGATTServer.startBonding(forceRePair)

Parameters

forceRePair - If the device is already bonded, re-pair it

Returns

A Promise that is resolved (or rejected) when the bonding is complete

Description

Start negotiating bonding (secure communications) with the connected device, and return a Promise that is completed on success or failure.

var gatt;
NRF.requestDevice({ filters: [{ name: 'Puck.js abcd' }] }).then(function(device) {
  console.log("found device");
  return device.gatt.connect();
}).then(function(g) {
  gatt = g;
  console.log("connected");
  return gatt.startBonding();
}).then(function() {
  console.log("bonded", gatt.getSecurityStatus());
  gatt.disconnect();
}).catch(function(e) {
  console.log("ERROR",e);
});

This is not part of the Web Bluetooth Specification. It has been added specifically for Espruino.

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

BluetoothRemoteGATTService Class

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Web Bluetooth-style GATT service - get this using BluetoothRemoteGATTServer.getPrimaryService(s)

https://webbluetoothcg.github.io/web-bluetooth/#bluetoothremotegattservice

Methods and Fields

function BluetoothRemoteGATTService.getCharacteristic

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Call type:

function BluetoothRemoteGATTService.getCharacteristic(characteristic)

Parameters

characteristic - The characteristic UUID

Returns

A Promise that is resolved (or rejected) when the characteristic is found (the argument contains a BluetoothRemoteGATTCharacteristic)

Description

See NRF.connect for usage examples.

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q) and ESP32 boards

function BluetoothRemoteGATTService.getCharacteristics

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Call type:

function BluetoothRemoteGATTService.getCharacteristics()

Returns

A Promise that is resolved (or rejected) when the characteristic is found (the argument contains an array of BluetoothRemoteGATTCharacteristic)

Boolean Class

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Methods and Fields

constructor Boolean

View MDN documentation

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Call type:

new Boolean(value)

Parameters

value - A single value to be converted to a number

Returns

A Boolean object

Description

Creates a boolean

console Class

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An Object that contains functions for writing to the interactive console

Methods and Fields

console.log

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Call type:

console.log(text, ...)

Parameters

text, ... - One or more arguments to print

Description

Print the supplied string(s) to the console

Note: If you're connected to a computer (not a wall adaptor) via USB but you are not running a terminal app then when you print data Espruino may pause execution and wait until the computer requests the data it is trying to print.

Examples

This function is used in the following places in Espruino's documentation

DataView Class

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This class helps

Methods and Fields

constructor DataView

View MDN documentation

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Call type:

new DataView(buffer, byteOffset, byteLength)

Parameters

buffer - The ArrayBuffer to base this on

byteOffset - (optional) The offset of this view in bytes

byteLength - (optional) The length in bytes

Returns

A DataView object

Description

Create a DataView object that can be used to access the data in an ArrayBuffer.

var b = new ArrayBuffer(8)
var v = new DataView(b)
v.setUint16(0,"0x1234")
v.setUint8(3,"0x56")
console.log("0x"+v.getUint32(0).toString(16))
// prints 0x12340056

Note: This is not available in devices with low flash memory

function DataView.getFloat32

View MDN documentation

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Call type:

function DataView.getFloat32(byteOffset, littleEndian)

Parameters

byteOffset - The offset in bytes to read from

littleEndian - (optional) Whether to read in little endian - if false or undefined data is read as big endian

Returns

the index of the value in the array, or -1

function DataView.getFloat64

View MDN documentation

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Call type:

function DataView.getFloat64(byteOffset, littleEndian)

Parameters

byteOffset - The offset in bytes to read from

littleEndian - (optional) Whether to read in little endian - if false or undefined data is read as big endian

Returns

the index of the value in the array, or -1

function DataView.getInt16

View MDN documentation

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Call type:

function DataView.getInt16(byteOffset, littleEndian)

Parameters

byteOffset - The offset in bytes to read from

littleEndian - (optional) Whether to read in little endian - if false or undefined data is read as big endian

Returns

the index of the value in the array, or -1

function DataView.getInt32

View MDN documentation

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Call type:

function DataView.getInt32(byteOffset, littleEndian)

Parameters

byteOffset - The offset in bytes to read from

littleEndian - (optional) Whether to read in little endian - if false or undefined data is read as big endian

Returns

the index of the value in the array, or -1

function DataView.getInt8

View MDN documentation

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Call type:

function DataView.getInt8(byteOffset, littleEndian)

Parameters

byteOffset - The offset in bytes to read from

littleEndian - (optional) Whether to read in little endian - if false or undefined data is read as big endian

Returns

the index of the value in the array, or -1

function DataView.getUint16

View MDN documentation

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Call type:

function DataView.getUint16(byteOffset, littleEndian)

Parameters

byteOffset - The offset in bytes to read from

littleEndian - (optional) Whether to read in little endian - if false or undefined data is read as big endian

Returns

the index of the value in the array, or -1

function DataView.getUint32

View MDN documentation

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Call type:

function DataView.getUint32(byteOffset, littleEndian)

Parameters

byteOffset - The offset in bytes to read from

littleEndian - (optional) Whether to read in little endian - if false or undefined data is read as big endian

Returns

the index of the value in the array, or -1

function DataView.getUint8

View MDN documentation

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Call type:

function DataView.getUint8(byteOffset, littleEndian)

Parameters

byteOffset - The offset in bytes to read from

littleEndian - (optional) Whether to read in little endian - if false or undefined data is read as big endian

Returns

the index of the value in the array, or -1

Examples

This function is used in the following places in Espruino's documentation

function DataView.setFloat32

View MDN documentation

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Call type:

function DataView.setFloat32(byteOffset, value, littleEndian)

Parameters

byteOffset - The offset in bytes to read from

value - The value to write

littleEndian - (optional) Whether to read in little endian - if false or undefined data is read as big endian

function DataView.setFloat64

View MDN documentation

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Call type:

function DataView.setFloat64(byteOffset, value, littleEndian)

Parameters

byteOffset - The offset in bytes to read from

value - The value to write

littleEndian - (optional) Whether to read in little endian - if false or undefined data is read as big endian

function DataView.setInt16

View MDN documentation

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Call type:

function DataView.setInt16(byteOffset, value, littleEndian)

Parameters

byteOffset - The offset in bytes to read from

value - The value to write

littleEndian - (optional) Whether to read in little endian - if false or undefined data is read as big endian

function DataView.setInt32

View MDN documentation

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Call type:

function DataView.setInt32(byteOffset, value, littleEndian)

Parameters

byteOffset - The offset in bytes to read from

value - The value to write

littleEndian - (optional) Whether to read in little endian - if false or undefined data is read as big endian

function DataView.setInt8

View MDN documentation

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Call type:

function DataView.setInt8(byteOffset, value, littleEndian)

Parameters

byteOffset - The offset in bytes to read from

value - The value to write

littleEndian - (optional) Whether to read in little endian - if false or undefined data is read as big endian

function DataView.setUint16

View MDN documentation

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Call type:

function DataView.setUint16(byteOffset, value, littleEndian)

Parameters

byteOffset - The offset in bytes to read from

value - The value to write

littleEndian - (optional) Whether to read in little endian - if false or undefined data is read as big endian

Examples

This function is used in the following places in Espruino's documentation

function DataView.setUint32

View MDN documentation

(top)

Call type:

function DataView.setUint32(byteOffset, value, littleEndian)

Parameters

byteOffset - The offset in bytes to read from

value - The value to write

littleEndian - (optional) Whether to read in little endian - if false or undefined data is read as big endian

function DataView.setUint8

View MDN documentation

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Call type:

function DataView.setUint8(byteOffset, value, littleEndian)

Parameters

byteOffset - The offset in bytes to read from

value - The value to write

littleEndian - (optional) Whether to read in little endian - if false or undefined data is read as big endian

Date Class

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The built-in class for handling Dates.

Note: By default the time zone is GMT+0, however you can change the timezone using the E.setTimeZone(...) function.

For example E.setTimeZone(1) will be GMT+0100

Methods and Fields

constructor Date

View MDN documentation

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Call type:

new Date(args, ...)

Parameters

args, ... - Either nothing (current time), one numeric argument (milliseconds since 1970), a date string (see Date.parse), or [year, month, day, hour, minute, second, millisecond]

Returns

A Date object

Description

Creates a date object

Examples

This function is used in the following places in Espruino's documentation

function Date.getDate

View MDN documentation

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Call type:

function Date.getDate()

Returns

See description above

Description

Day of the month 1..31

function Date.getDay

View MDN documentation

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Call type:

function Date.getDay()

Returns

See description above

Description

Day of the week (0=sunday, 1=monday, etc)

function Date.getFullYear

View MDN documentation

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Call type:

function Date.getFullYear()

Returns

See description above

Description

The year, eg. 2014

function Date.getHours

View MDN documentation

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Call type:

function Date.getHours()

Returns

See description above

Description

0..23

function Date.getMilliseconds

View MDN documentation

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Call type:

function Date.getMilliseconds()

Returns

See description above

Description

0..999

function Date.getMinutes

View MDN documentation

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Call type:

function Date.getMinutes()

Returns

See description above

Description

0..59

function Date.getMonth

View MDN documentation

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Call type:

function Date.getMonth()

Returns

See description above

Description

Month of the year 0..11

function Date.getSeconds

View MDN documentation

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Call type:

function Date.getSeconds()

Returns

See description above

Description

0..59

function Date.getTime

View MDN documentation

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Call type:

function Date.getTime()

Returns

See description above

Description

Return the number of milliseconds since 1970

function Date.getTimezoneOffset

View MDN documentation

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Call type:

function Date.getTimezoneOffset()

Returns

The difference, in minutes, between UTC and local time

Description

This returns Espruino's time-zone offset from UTC, in minutes.

This is set with E.setTimeZone and is System-wide. The value returned has nothing to do with the instance of Date that it is called on.

Note: This is not available in devices with low flash memory

Date.now

View MDN documentation

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Call type:

Date.now()

Returns

See description above

Description

Get the number of milliseconds elapsed since 1970 (or on embedded platforms, since startup)

Examples

This function is used in the following places in Espruino's documentation

Date.parse

View MDN documentation

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Call type:

Date.parse(str)

Parameters

str - A String

Returns

The number of milliseconds since 1970

Description

Parse a date string and return milliseconds since 1970. Data can be either '2011-10-20T14:48:00', '2011-10-20' or 'Mon, 25 Dec 1995 13:30:00 +0430'

Examples

This function is used in the following places in Espruino's documentation

function Date.setDate

View MDN documentation

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Call type:

function Date.setDate(dayValue)

Parameters

dayValue - the day of the month, between 0 and 31

Returns

The number of milliseconds since 1970

Description

Day of the month 1..31

Note: This is not available in devices with low flash memory

function Date.setFullYear

View MDN documentation

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Call type:

function Date.setFullYear(yearValue, yearValue, dayValue)

Parameters

yearValue - The full year - eg. 1989

yearValue - optional - the month, between 0 and 11

dayValue - optional - the day, between 0 and 31

Returns

The number of milliseconds since 1970

function Date.setHours

View MDN documentation

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Call type:

function Date.setHours(hoursValue, minutesValue, secondsValue, millisecondsValue)

Parameters

hoursValue - number of hours, 0..23

minutesValue - number of minutes, 0..59

secondsValue - optional - number of seconds, 0..59

millisecondsValue - optional - number of milliseconds, 0..999

Returns

The number of milliseconds since 1970

Description

0..23

Note: This is not available in devices with low flash memory

function Date.setMilliseconds

View MDN documentation

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Call type:

function Date.setMilliseconds(millisecondsValue)

Parameters

millisecondsValue - number of milliseconds, 0..999

Returns

The number of milliseconds since 1970

function Date.setMinutes

View MDN documentation

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Call type:

function Date.setMinutes(minutesValue, secondsValue, millisecondsValue)

Parameters

minutesValue - number of minutes, 0..59

secondsValue - optional - number of seconds, 0..59

millisecondsValue - optional - number of milliseconds, 0..999

Returns

The number of milliseconds since 1970

Description

0..59

Note: This is not available in devices with low flash memory

function Date.setMonth

View MDN documentation

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Call type:

function Date.setMonth(yearValue, dayValue)

Parameters

yearValue - The month, between 0 and 11

dayValue - optional - the day, between 0 and 31

Returns

The number of milliseconds since 1970

Description

Month of the year 0..11

Note: This is not available in devices with low flash memory

function Date.setSeconds

View MDN documentation

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Call type:

function Date.setSeconds(secondsValue, millisecondsValue)

Parameters

secondsValue - number of seconds, 0..59

millisecondsValue - optional - number of milliseconds, 0..999

Returns

The number of milliseconds since 1970

Description

0..59

Note: This is not available in devices with low flash memory

function Date.setTime

View MDN documentation

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Call type:

function Date.setTime(timeValue)

Parameters

timeValue - the number of milliseconds since 1970

Returns

the number of milliseconds since 1970

Description

Set the time/date of this Date class

function Date.toISOString

View MDN documentation

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Call type:

function Date.toISOString()

Returns

A String

Description

Converts to a ISO 8601 String, eg: 2014-06-20T14:52:20.123Z

Note: This always assumes a timezone of GMT

function Date.toJSON

View MDN documentation

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Call type:

function Date.toJSON()

Returns

A String

Description

Calls Date.toISOString to output this date to JSON

function Date.toString

View MDN documentation

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Call type:

function Date.toString()

Returns

A String

Description

Converts to a String, eg: Fri Jun 20 2014 14:52:20 GMT+0000

Note: This uses whatever timezone was set with E.setTimeZone()

function Date.toUTCString

View MDN documentation

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Call type:

function Date.toUTCString()

Returns

A String

Description

Converts to a String, eg: Fri, 20 Jun 2014 14:52:20 GMT

Note: This always assumes a timezone of GMT

function Date.valueOf

View MDN documentation

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Call type:

function Date.valueOf()

Returns

See description above

Description

Return the number of milliseconds since 1970

E Class

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This is the built-in JavaScript class for Espruino utility functions.

Methods and Fields

E.asm

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Call type:

E.asm(callspec, assemblycode, ...)

Parameters

callspec - The arguments this assembly takes - eg void(int)

assemblycode, ... - One of more strings of assembler code

Description

Provide assembly to Espruino.

This function is not part of Espruino. Instead, it is detected by the Espruino IDE (or command-line tools) at upload time and is replaced with machine code and an E.nativeCall call.

See the documentation on the Assembler for more information.

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

E.clip

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Call type:

E.clip(x, min, max)

Parameters

x - A floating point value to clip

min - The smallest the value should be

max - The largest the value should be

Returns

The value of x, clipped so as not to be below min or above max.

Description

Clip a number to be between min and max (inclusive)

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

E.compiledC

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Call type:

E.compiledC(code)

Parameters

code - A Templated string of C code

Description

Provides the ability to write C code inside your JavaScript file.

This function is not part of Espruino. Instead, it is detected by the Espruino IDE (or command-line tools) at upload time, is sent to our web service to be compiled, and is replaced with machine code and an E.nativeCall call.

See the documentation on Inline C for more information and examples.

Note: This is not available in devices with low flash memory

E.convolve

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Call type:

E.convolve(arr1, arr2, offset)

Parameters

arr1 - An array to convolve

arr2 - An array to convolve

offset - The mean value of the array

Returns

The variance of the given buffer

Description

Convolve arr1 with arr2. This is equivalent to v=0;for (i in arr1) v+=arr1[i] * arr2[(i+offset) % arr2.length]

Note: This is not available in devices with low flash memory

E.CRC32

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Call type:

E.CRC32(data)

Parameters

data - Iterable data to perform CRC32 on (each element treated as a byte)

Returns

The CRC of the supplied data

Description

Perform a standard 32 bit CRC (Cyclic redundancy check) on the supplied data (one byte at a time) and return the result as an unsigned integer.

Note: This is not available in devices with low flash memory

E.defrag

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Call type:

E.defrag()

Description

BETA: defragment memory!

Note: This is not available in devices with low flash memory

E.dumpFragmentation

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Call type:

E.dumpFragmentation()

Description

Show fragmentation.

E.dumpFreeList

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Call type:

E.dumpFreeList()

Description

Dump any locked variables that aren't referenced from global - for debugging memory leaks only.

Note: This is not available in release builds

E.dumpLockedVars

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Call type:

E.dumpLockedVars()

Description

Dump any locked variables that aren't referenced from global - for debugging memory leaks only.

Note: This is not available in release builds

E.dumpStr

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Call type:

E.dumpStr()

Returns

A String

Description

Get the current interpreter state in a text form such that it can be copied to a new device

Note: This is not available in devices with low flash memory

E.dumpTimers

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Call type:

E.dumpTimers()

Description

Output the current list of Utility Timer Tasks - for debugging only

Note: This is not available in release builds

E.dumpVariables

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Call type:

E.dumpVariables()

Description

Dumps a comma-separated list of all allocated variables along with the variables they link to. Can be used to visualise where memory is used.

Note: This is not available in devices with low flash memory

E.enableWatchdog

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Call type:

E.enableWatchdog(timeout, isAuto)

Parameters

timeout - The timeout in seconds before a watchdog reset

isAuto - If undefined or true, the watchdog is kicked automatically. If not, you must call E.kickWatchdog() yourself

Description

Enable the watchdog timer. This will reset Espruino if it isn't able to return to the idle loop within the timeout.

If isAuto is false, you must call E.kickWatchdog() yourself every so often or the chip will reset.

E.enableWatchdog(0.5); // automatic mode                                                        
while(1); // Espruino will reboot because it has not been idle for 0.5 sec

E.enableWatchdog(1, false);                                                         
setInterval(function() {
  if (everything_ok)
    E.kickWatchdog();
}, 500);
// Espruino will now reset if everything_ok is false,
// or if the interval fails to be called

NOTE: This is only implemented on STM32 and nRF5x devices (all official Espruino boards).

NOTE: On STM32 (Pico, WiFi, Original) with setDeepSleep(1) you need to explicitly wake Espruino up with an interval of less than the watchdog timeout or the watchdog will fire and the board will reboot. You can do this with setInterval("", time_in_milliseconds).

Note: This is not available in devices with low flash memory

event E.errorFlag

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Call type:

E.on('errorFlag', function(errorFlags) { ... });

Parameters

errorFlags - An array of new error flags, as would be returned by E.getErrorFlags(). Error flags that were present before won't be reported.

Description

This event is called when an error is created by Espruino itself (rather than JS code) which changes the state of the error flags reported by E.getErrorFlags()

This could be low memory, full buffers, UART overflow, etc. E.getErrorFlags() has a full description of each type of error.

This event will only be emitted when error flag is set. If the error flag was already set nothing will be emitted. To clear error flags so that you do get a callback each time a flag is set, call E.getErrorFlags().

E.FFT

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Call type:

E.FFT(arrReal, arrImage, inverse)

Parameters

arrReal - An array of real values

arrImage - An array of imaginary values (or if undefined, all values will be taken to be 0)

inverse - Set this to true if you want an inverse FFT - otherwise leave as 0

Description

Performs a Fast Fourier Transform (FFT) in 32 bit floats on the supplied data and writes it back into the original arrays. Note that if only one array is supplied, the data written back is the modulus of the complex result sqrt(r*r+i*i).

In order to perform the FFT, there has to be enough room on the stack to allocate two arrays of 32 bit floating point numbers - this will limit the maximum size of FFT possible to around 1024 items on most platforms.

Note: on the Original Espruino board, FFTs are performed in 64bit arithmetic as there isn't space to include the 32 bit maths routines (2x more RAM is required).

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

E.getAddressOf

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Call type:

E.getAddressOf(v, flatAddress)

Parameters

v - A variable to get the address of

flatAddress - (boolean) If true and a Flat String or Flat ArrayBuffer is supplied, return the address of the data inside it - otherwise 0. If false (the default) return the address of the JsVar itself.

Returns

The address of the given variable

Description

Return the address in memory of the given variable. This can then be used with peek and poke functions. However, changing data in JS variables directly (flatAddress=false) will most likely result in a crash.

This functions exists to allow embedded targets to set up peripherals such as DMA so that they write directly to JS variables.

See http://www.espruino.com/Internals for more information

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

E.getAnalogVRef

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Call type:

E.getAnalogVRef()

Returns

The voltage (in Volts) that a reading of 1 from analogRead actually represents - usually around 3.3v

Description

Check the internal voltage reference. To work out an actual voltage of an input pin, you can use analogRead(pin)*E.getAnalogVRef()

Note: This value is calculated by reading the voltage on an internal voltage reference with the ADC. It will be slightly noisy, so if you need this for accurate measurements we'd recommend that you call this function several times and average the results.

While this is implemented on Espruino boards, it may not be implemented on other devices. If so it'll return NaN.

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

E.getBattery

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Call type:

E.getBattery()

Returns

A percentage between 0 and 100

Description

In devices that come with batteries, this function returns the battery charge percentage as an integer between 0 and 100.

Note: this is an estimation only, based on battery voltage. The temperature of the battery (as well as the load being drawn from it at the time E.getBattery is called) will affect the readings.

Note: This is only available in Puck.js devices and Pixl.js boards and Bangle.js smartwatches

E.getConsole

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Call type:

E.getConsole()

Returns

The current console device as a string, or just null if the console is null

Description

Returns the current console device - see E.setConsole for more information.

E.getErrorFlags

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Call type:

E.getErrorFlags()

Returns

An array of error flags

Description

Get and reset the error flags. Returns an array that can contain:

'FIFO_FULL': The receive FIFO filled up and data was lost. This could be state transitions for setWatch, or received characters.

'BUFFER_FULL': A buffer for a stream filled up and characters were lost. This can happen to any stream - Serial,HTTP,etc.

'CALLBACK': A callback (setWatch, setInterval, on('data',...)) caused an error and so was removed.

'LOW_MEMORY': Memory is running low - Espruino had to run a garbage collection pass or remove some of the command history

'MEMORY': Espruino ran out of memory and was unable to allocate some data that it needed.

'UART_OVERFLOW' : A UART received data but it was not read in time and was lost

Note: This is not available in devices with low flash memory

E.getFlags

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Call type:

E.getFlags()

Returns

An object containing flag names and their values

Description

Get Espruino's interpreter flags that control the way it handles your JavaScript code.

E.getSizeOf

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Call type:

E.getSizeOf(v, depth)

Parameters

v - A variable to get the size of

depth - The depth that detail should be provided for. If depth<=0 or undefined, a single integer will be returned

Returns

Information about the variable size - see below

Description

Return the number of variable blocks used by the supplied variable. This is useful if you're running out of memory and you want to be able to see what is taking up most of the available space.

If depth>0 and the variable can be recursed into, an array listing all property names (including internal Espruino names) and their sizes is returned. If depth>1 there is also a more field that inspects the objects's children's children.

For instance E.getSizeOf(function(a,b) { }) returns 5.

But E.getSizeOf(function(a,b) { }, 1) returns:

[
  {
    "name": "a",
    "size": 1 },
  {
    "name": "b",
    "size": 1 },
  {
    "name": "\xFFcod",
    "size": 2 }
 ]

In this case setting depth to 2 will make no difference as there are no more children to traverse.

See http://www.espruino.com/Internals for more information

Note: This is not available in devices with low flash memory

E.getTemperature

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Call type:

E.getTemperature()

Returns

The temperature in degrees C

Description

Use the STM32's internal thermistor to work out the temperature.

While this is implemented on Espruino boards, it may not be implemented on other devices. If so it'll return NaN.

Note: This is not entirely accurate and varies by a few degrees from chip to chip. It measures the die temperature, so when connected to USB it could be reading 10 over degrees C above ambient temperature. When running from battery with setDeepSleep(true) it is much more accurate though.

Examples

This function is used in the following places in Espruino's documentation

E.HSBtoRGB

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Call type:

E.HSBtoRGB(hue, sat, bri, asArray)

Parameters

hue - The hue, as a value between 0 and 1

sat - The saturation, as a value between 0 and 1

bri - The brightness, as a value between 0 and 1

asArray - If true, return an array of [R,G,B] values betwen 0 and 255

Returns

A 24 bit number containing bytes representing red, green, and blue 0xBBGGRR. Or if asArray is true, an array [R,G,B]

Description

Convert hue, saturation and brightness to red, green and blue (packed into an integer if asArray==false or an array if asArray==true).

This replaces Graphics.setColorHSB and Graphics.setBgColorHSB. On devices with 24 bit colour it can be used as: Graphics.setColor(E.HSBtoRGB(h, s, b))

You can quickly set RGB items in an Array or Typed Array using array.set(E.HSBtoRGB(h, s, b,true), offset), which can be useful with arrays used with require("neopixel").write.

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

E.hwRand

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Call type:

E.hwRand()

Returns

A random number

Description

Unlike 'Math.random()' which uses a pseudo-random number generator, this method reads from the internal voltage reference several times, xoring and rotating to try and make a relatively random value from the noise in the signal.

Note: This is not available in devices with low flash memory

event E.init

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Call type:

E.on('init', function() { ... });

Description

This event is called right after the board starts up, and has a similar effect to creating a function called onInit.

For example to write "Hello World" every time Espruino starts, use:

E.on('init', function() {
  console.log("Hello World!");
});

Note: that subsequent calls to E.on('init', will add a new handler, rather than replacing the last one. This allows you to write modular code - something that was not possible with onInit.

E.interpolate

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Call type:

E.interpolate(array, index)

Parameters

array - A Typed Array to interpolate between

index - Floating point index to access

Returns

The result of interpolating between (int)index and (int)(index+1)

Description

Interpolate between two adjacent values in the Typed Array

Note: This is not available in devices with low flash memory

E.interpolate2d

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Call type:

E.interpolate2d(array, width, x, y)

Parameters

array - A Typed Array to interpolate between

width - Integer 'width' of 2d array

x - Floating point X index to access

y - Floating point Y index to access

Returns

The result of interpolating in 2d between the 4 surrounding cells

Description

Interpolate between four adjacent values in the Typed Array, in 2D.

Note: This is not available in devices with low flash memory

E.kickWatchdog

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Call type:

E.kickWatchdog()

Description

Kicks a Watchdog timer set up with E.enableWatchdog(..., false). See E.enableWatchdog for more information.

NOTE: This is only implemented on STM32 and nRF5x devices (all official Espruino boards).

Note: This is not available in devices with low flash memory

event E.kill

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Call type:

E.on('kill', function() { ... });

Description

This event is called just before the device shuts down for commands such as reset(), load(), save(), E.reboot() or Bangle.off()

For example to write "Bye!" just before shutting down use:

E.on('kill', function() {
  console.log("Bye!");
});

NOTE: This event is not called when the device is 'hard reset' - for example by removing power, hitting an actual reset button, or via a Watchdog timer reset.

E.lockConsole

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Call type:

E.lockConsole()

Description

If a password has been set with E.setPassword(), this will lock the console so the password needs to be entered to unlock it.

E.lookupNoCase

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Call type:

E.lookupNoCase(haystack, needle, returnKey)

Parameters

haystack - The Array/Object/Function to search

needle - The key to search for

returnKey - If true, return the key, else return the value itself

Returns

The value in the Object matching 'needle', or if returnKey==true the key's name - or undefined

Description

Search in an Object, Array, or Function

E.mapInPlace

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Call type:

E.mapInPlace(from, to, map, bits)

Parameters

from - An ArrayBuffer to read elements from

to - An ArrayBuffer to write elements too

map - An array or function(value,index) to use to map one element to another, or undefined to provide no mapping

bits - If specified, the number of bits per element (MSB first) - otherwise use a 1:1 mapping. If negative, use LSB first.

Description

Take each element of the from array, look it up in map (or call map(value,index) if it is a function), and write it into the corresponding element in the to array.

You can use an array to map:

var a = new Uint8Array([1,2,3,1,2,3]);
var lut = new Uint8Array([128,129,130,131]);
E.mapInPlace(a, a, lut);
// a = [129, 130, 131, 129, 130, 131]

Or undefined to pass straight through, or a function to do a normal 'mapping':

var a = new Uint8Array([0x12,0x34,0x56,0x78]);
var b = new Uint8Array(8);
E.mapInPlace(a, b, undefined); // straight through
// b = [0x12,0x34,0x56,0x78,0,0,0,0]
E.mapInPlace(a, b, (value,index)=>index); // write the index in the first 4 (because a.length==4)
// b = [0,1,2,3,4,0,0,0]
E.mapInPlace(a, b, undefined, 4); // 4 bits from 8 bit input -> 2x as many outputs, msb-first
// b = [1, 2, 3, 4, 5, 6, 7, 8]
 E.mapInPlace(a, b, undefined, -4); // 4 bits from 8 bit input -> 2x as many outputs, lsb-first
// b = [2, 1, 4, 3, 6, 5, 8, 7]
E.mapInPlace(a, b, a=>a+2, 4);
// b = [3, 4, 5, 6, 7, 8, 9, 10]
var b = new Uint16Array(4);
E.mapInPlace(a, b, undefined, 12); // 12 bits from 8 bit input, msb-first
// b = [0x123, 0x456, 0x780, 0]
E.mapInPlace(a, b, undefined, -12); // 12 bits from 8 bit input, lsb-first
// b = [0x412, 0x563, 0x078, 0]

Note: This is not available in devices with low flash memory

E.memoryArea

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Call type:

E.memoryArea(addr, len)

Parameters

addr - The address of the memory area

len - The length (in bytes) of the memory area

Returns

A String

Description

This creates and returns a special type of string, which actually references a specific memory address. It can be used in order to use sections of Flash memory directly in Espruino (for example to execute code straight from flash memory with eval(E.memoryArea( ... )))

Note: This is only tested on STM32-based platforms (Espruino Original and Espruino Pico) at the moment.

Examples

This function is used in the following places in Espruino's documentation

E.memoryMap

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Call type:

E.memoryMap(baseAddress, registers)

Parameters

baseAddress - The base address (added to every address in registers)

registers - An object containing {name:address}

Returns

An object where each field is memory-mapped to a register.

Description

Create an object where every field accesses a specific 32 bit address in the microcontroller's memory. This is perfect for accessing on-chip peripherals.

// for NRF52 based chips
var GPIO = E.memoryMap(0x50000000,{OUT:0x504, OUTSET:0x508, OUTCLR:0x50C, IN:0x510, DIR:0x514, DIRSET:0x518, DIRCLR:0x51C});
GPIO.DIRSET = 1; // set GPIO0 to output
GPIO.OUT ^= 1; // toggle the output state of GPIO0

Note: This is not available in devices with low flash memory

E.nativeCall

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Call type:

E.nativeCall(addr, sig, data)

Parameters

addr - The address in memory of the function (or offset in data if it was supplied

sig - The signature of the call, returnType (arg1,arg2,...). Allowed types are void,bool,int,double,Pin,JsVar

data - (Optional) A string containing the function itself. If not supplied then 'addr' is used as an absolute address.

Returns

The native function

Description

ADVANCED: This is a great way to crash Espruino if you're not sure what you are doing

Create a native function that executes the code at the given address. Eg. E.nativeCall(0x08012345,'double (double,double)')(1.1, 2.2)

If you're executing a thumb function, you'll almost certainly need to set the bottom bit of the address to 1.

Note it's not guaranteed that the call signature you provide can be used - there are limits on the number of arguments allowed.

When supplying data, if it is a 'flat string' then it will be used directly, otherwise it'll be converted to a flat string and used.

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

E.pipe

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Call type:

E.pipe(source, destination, options)

Parameters

source - The source file/stream that will send content.

destination - The destination file/stream that will receive content from the source.

options - An optional object { chunkSize : int=64, end : bool=true, complete : function }
chunkSize : The amount of data to pipe from source to destination at a time
complete : a function to call when the pipe activity is complete
end : call the 'end' function on the destination when the source is finished

E.reboot

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Call type:

E.reboot()

Description

Forces a hard reboot of the microcontroller - as close as possible to if the reset pin had been toggled.

Note: This is different to reset(), which performs a software reset of Espruino (resetting the interpreter and pin states, but not all the hardware)

E.reverseByte

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Call type:

E.reverseByte(x)

Parameters

x - A byte value to reverse the bits of

Returns

The byte with reversed bits

Description

Reverse the 8 bits in a byte, swapping MSB and LSB.

For example, E.reverseByte(0b10010000) == 0b00001001.

Note that you can reverse all the bytes in an array with: arr = arr.map(E.reverseByte)

Note: This is not available in devices with low flash memory

E.setBootCode

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Call type:

E.setBootCode(code, alwaysExec)

Parameters

code - The code to execute (as a string)

alwaysExec - Whether to always execute the code (even after a reset)

Description

This writes JavaScript code into Espruino's flash memory, to be executed on startup. It differs from save() in that save() saves the whole state of the interpreter, whereas this just saves JS code that is executed at boot.

Code will be executed before onInit() and E.on('init', ...).

If alwaysExec is true, the code will be executed even after a call to reset(). This is useful if you're making something that you want to program, but you want some code that is always built in (for instance setting up a display or keyboard).

To remove boot code that has been saved previously, use E.setBootCode("")

Note: this removes any code that was previously saved with save()

E.setClock

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Call type:

E.setClock(options)

Parameters

options - Platform-specific options for setting clock speed

Returns

The actual frequency the clock has been set to

Description

This sets the clock frequency of Espruino's processor. It will return 0 if it is unimplemented or the clock speed cannot be changed.

Note: On pretty much all boards, UART, SPI, I2C, PWM, etc will change frequency and will need setting up again in order to work.

STM32F4

Options is of the form { M: int, N: int, P: int, Q: int } - see the 'Clocks' section of the microcontroller's reference manual for what these mean.

Optional arguments are:

The Pico's default is {M:8, N:336, P:4, Q:7, PCLK1:2, PCLK2:4}, use {M:8, N:336, P:8, Q:7, PCLK:1, PCLK2:2} to halve the system clock speed while keeping the peripherals running at the same speed (omitting PCLK1/2 will lead to the peripherals changing speed too).

On STM32F4 boards (eg. Espruino Pico), the USB clock needs to be kept at 48Mhz or USB will fail to work. You'll also experience USB instability if the processor clock falls much below 48Mhz.

ESP8266

Just specify an integer value, either 80 or 160 (for 80 or 160Mhz)

Note: This is not available in devices with low flash memory

E.setConsole

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Call type:

E.setConsole(device, options)

Parameters

device -

options - (optional) object of options, see below

Description

Changes the device that the JS console (otherwise known as the REPL) is attached to. If the console is on a device, that device can be used for programming Espruino.

Rather than calling Serial.setConsole you can call E.setConsole("DeviceName").

This is particularly useful if you just want to remove the console. E.setConsole(null) will make the console completely inaccessible.

device may be "Serial1","USB","Bluetooth","Telnet","Terminal", any other hardware Serial device, or null to disable the console completely.

options is of the form:

{
  force : bool // default false, force the console onto this device so it does not move
               //   if false, changes in connection state (eg USB/Bluetooth) can move
               //   the console automatically.
}

Note: This is not available in devices with low flash memory

E.setFlags

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Call type:

E.setFlags(flags)

Parameters

flags - An object containing flag names and boolean values. You need only specify the flags that you want to change.

Description

Set the Espruino interpreter flags that control the way it handles your JavaScript code.

Run E.getFlags() and check its description for a list of available flags and their values.

E.setPassword

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Call type:

E.setPassword(password)

Parameters

password - The password - max 20 chars

Description

Set a password on the console (REPL). When powered on, Espruino will then demand a password before the console can be used. If you want to lock the console immediately after this you can call E.lockConsole()

To remove the password, call this function with no arguments.

Note: There is no protection against multiple password attempts, so someone could conceivably try every password in a dictionary.

Note: This password is stored in memory in plain text. If someone is able to execute arbitrary JavaScript code on the device (eg, you use eval on input from unknown sources) or read the device's firmware then they may be able to obtain it.

E.setTimeZone

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Call type:

E.setTimeZone(zone)

Parameters

zone - The time zone in hours

Description

Set the time zone to be used with Date objects.

For example E.setTimeZone(1) will be GMT+0100

Time can be set with setTime.

E.showAlert

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Call type:

E.showAlert(message, options)

Parameters

message - A message to display. Can include newlines

options - (optional) a title for the message

Returns

A promise that is resolved when 'Ok' is pressed

Description

Displays a full screen prompt on the screen, with a single 'Ok' button.

When the button is pressed the promise is resolved.

E.showAlert("Hello").then(function() {
  print("Ok pressed");
});
// or
E.showAlert("These are\nLots of\nLines","My Title").then(function() {
  print("Ok pressed");
});

To remove the window, call E.showAlert() with no arguments.

Note: This is only available in Bangle.js smartwatches

E.showMenu

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Call type:

E.showMenu(menu)

Parameters

menu - An object containing name->function mappings to to be used in a menu

Returns

A menu object with draw, move and select functions

Description

Display a menu on the screen, and set up the buttons to navigate through it.

Supply an object containing menu items. When an item is selected, the function it references will be executed. For example:

var boolean = false;
var number = 50;
// First menu
var mainmenu = {
  "" : { "title" : "-- Main Menu --" },
  "Backlight On" : function() { LED1.set(); },
  "Backlight Off" : function() { LED1.reset(); },
  "Submenu" : function() { E.showMenu(submenu); },
  "A Boolean" : {
    value : boolean,
    format : v => v?"On":"Off",
    onchange : v => { boolean=v; }
  },
  "A Number" : {
    value : number,
    min:0,max:100,step:10,
    onchange : v => { number=v; }
  },
  "Exit" : function() { E.showMenu(); },
};
// Submenu
var submenu = {
  "" : { "title" : "-- SubMenu --" },
  "One" : undefined, // do nothing
  "Two" : undefined, // do nothing
  "< Back" : function() { E.showMenu(mainmenu); },
};
// Actually display the menu
E.showMenu(mainmenu);

See http://www.espruino.com/graphical_menu for more detailed information.

Note: This is only available in Bangle.js smartwatches

E.showMessage

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Call type:

E.showMessage(message, title)

Parameters

message - A message to display. Can include newlines

title - (optional) a title for the message

Description

A utility function for displaying a full screen message on the screen.

Draws to the screen and returns immediately.

E.showMessage("These are\nLots of\nLines","My Title")

Note: This is only available in Bangle.js smartwatches

E.showPrompt

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Call type:

E.showPrompt(message, options)

Parameters

message - A message to display. Can include newlines

options - (optional) an object of options (see below)

Returns

A promise that is resolved when 'Ok' is pressed

Description

Displays a full screen prompt on the screen, with the buttons requested (or Yes and No for defaults).

When the button is pressed the promise is resolved with the requested values (for the Yes and No defaults, true and false are returned).

E.showPrompt("Do you like fish?").then(function(v) {
  if (v) print("'Yes' chosen");
  else print("'No' chosen");
});
// Or
E.showPrompt("How many fish\ndo you like?",{
  title:"Fish",
  buttons : {"One":1,"Two":2,"Three":3}
}).then(function(v) {
  print("You like "+v+" fish");
});

To remove the prompt, call E.showPrompt() with no arguments.

The second options argument can contain:

{
  title: "Hello",                      // optional Title
  buttons : {"Ok":true,"Cancel":false} // list of button text & return value
}

Note: This is only available in Bangle.js smartwatches

E.srand

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Call type:

E.srand(v)

Parameters

v - The 32 bit integer seed to use for the random number generator

Description

Set the seed for the random number generator used by Math.random().

Note: This is not available in devices with low flash memory

E.sum

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Call type:

E.sum(arr)

Parameters

arr - The array to sum

Returns

The sum of the given buffer

Description

Sum the contents of the given Array, String or ArrayBuffer and return the result

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

E.toArrayBuffer

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Call type:

E.toArrayBuffer(str)

Parameters

str - The string to convert to an ArrayBuffer

Returns

An ArrayBuffer that uses the given string

Description

Create an ArrayBuffer from the given string. This is done via a reference, not a copy - so it is very fast and memory efficient.

Note that this is an ArrayBuffer, not a Uint8Array. To get one of those, do: new Uint8Array(E.toArrayBuffer('....')).

Examples

This function is used in the following places in Espruino's documentation

E.toJS

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Call type:

E.toJS(arg)

Parameters

arg - The JS variable to convert to a string

Returns

A String

Description

This performs the same basic function as JSON.stringify, however JSON.stringify adds extra characters to conform to the JSON spec which aren't required if outputting JS.

E.toJS will also stringify JS functions, whereas JSON.stringify ignores them.

For example:

Note: Strings generated with E.toJS can't be reliably parsed by JSON.parse - however they are valid JS so will work with eval (but this has security implications if you don't trust the source of the string).

On the desktop JSON5 parsers will parse the strings produced by E.toJS without trouble.

E.toString

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Call type:

E.toString(args, ...)

Parameters

args, ... - The arguments to convert to a String

Returns

A String (or undefined if a Flat String cannot be created)

Description

Returns a 'flat' string representing the data in the arguments, or return undefined if a flat string cannot be created.

This creates a string from the given arguments. If an argument is a String or an Array, each element is traversed and added as an 8 bit character. If it is anything else, it is converted to a character directly.

In the case where there's one argument which is an 8 bit typed array backed by a flat string of the same length, the backing string will be returned without doing a copy or other allocation. The same applies if there's a single argument which is itself a flat string.

Examples

This function is used in the following places in Espruino's documentation

E.toUint8Array

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Call type:

E.toUint8Array(args, ...)

Parameters

args, ... - The arguments to convert to a Uint8Array

Returns

A Uint8Array

Description

This creates a Uint8Array from the given arguments. These are handled as follows:

For example:

E.toUint8Array([1,2,3])
=new Uint8Array([1, 2, 3])
E.toUint8Array([1,{data:2,count:3},3])
=new Uint8Array([1, 2, 2, 2, 3])
E.toUint8Array("Hello")
=new Uint8Array([72, 101, 108, 108, 111])
E.toUint8Array(["hi",{callback:function() { return [1,2,3] }}])
=new Uint8Array([104, 105, 1, 2, 3])

E.variance

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Call type:

E.variance(arr, mean)

Parameters

arr - The array to work out the variance for

mean - The mean value of the array

Returns

The variance of the given buffer

Description

Work out the variance of the contents of the given Array, String or ArrayBuffer and return the result. This is equivalent to v=0;for (i in arr) v+=Math.pow(mean-arr[i],2)

Note: This is not available in devices with low flash memory

Error Class

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The base class for runtime errors

Methods and Fields

constructor Error

View MDN documentation

(top)

Call type:

new Error(message)

Parameters

message - An optional message string

Returns

An Error object

Description

Creates an Error object

Examples

This function is used in the following places in Espruino's documentation

function Error.toString

View MDN documentation

(top)

Call type:

function Error.toString()

Returns

A String

Flash Library

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This module allows you to read and write the nonvolatile flash memory of your device.

Also see the Storage library, which provides a safer file-like interface to nonvolatile storage.

It should be used with extreme caution, as it is easy to overwrite parts of Flash memory belonging to Espruino or even its bootloader. If you damage the bootloader then you may need external hardware such as a USB-TTL converter to restore it. For more information on restoring the bootloader see Advanced Reflashing in your board's reference pages.

To see which areas of memory you can and can't overwrite, look at the values reported by process.memory().

Note: On Nordic platforms there are checks in place to help you avoid 'bricking' your device be damaging the bootloader. You can disable these with E.setFlags({unsafeFlash:1})

Methods and Fields

Flash.erasePage

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Call type:

require("Flash").erasePage(addr)

Parameters

addr - An address in the page that is to be erased

Description

Erase a page of flash memory

Note: This is not available in devices with low flash memory

Flash.getFree

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Call type:

require("Flash").getFree()

Returns

Array of objects with addr and length properties

Description

This method returns an array of objects of the form {addr : #, length : #}, representing contiguous areas of flash memory in the chip that are not used for anything.

The memory areas returned are on page boundaries. This means that you can safely erase the page containing any address here, and you won't risk deleting part of the Espruino firmware.

Note: This is not available in devices with low flash memory

Flash.getPage

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Call type:

require("Flash").getPage(addr)

Parameters

addr - An address in memory

Returns

An object of the form { addr : #, length : #}, where addr is the start address of the page, and length is the length of it (in bytes). Returns undefined if no page at address

Description

Returns the start and length of the flash page containing the given address.

Note: This is not available in devices with low flash memory

Flash.read

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Call type:

require("Flash").read(length, addr)

Parameters

length - The amount of data to read (in bytes)

addr - The address to start reading from

Returns

A Uint8Array of data

Description

Read flash memory from the given address

Note: This is not available in devices with low flash memory

Flash.write

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Call type:

require("Flash").write(data, addr)

Parameters

data - The data to write

addr - The address to start writing from

Description

Write data into memory at the given address

In flash memory you may only turn bits that are 1 into bits that are 0. If you're writing data into an area that you have already written (so read doesn't return all 0xFF) you'll need to call erasePage to clear the entire page.

Note: This is not available in devices with low flash memory

Float32Array Class

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This is the built-in JavaScript class for a typed array of 32 bit floating point values.

Instantiate this in order to efficiently store arrays of data (Espruino's normal arrays store data in a map, which is inefficient for non-sparse arrays).

Arrays of this type include all the methods from ArrayBufferView

Methods and Fields

constructor Float32Array

View MDN documentation

(top)

Call type:

new Float32Array(arr, byteOffset, length)

Parameters

arr - The array or typed array to base this off, or an integer which is the array length

byteOffset - The byte offset in the ArrayBuffer (ONLY IF the first argument was an ArrayBuffer)

length - The length (ONLY IF the first argument was an ArrayBuffer)

Returns

A typed array

Description

Create a typed array based on the given input. Either an existing Array Buffer, an Integer as a Length, or a simple array. If an ArrayBufferView (eg. Uint8Array rather than ArrayBuffer) is given, it will be completely copied rather than referenced.

Float64Array Class

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This is the built-in JavaScript class for a typed array of 64 bit floating point values.

Instantiate this in order to efficiently store arrays of data (Espruino's normal arrays store data in a map, which is inefficient for non-sparse arrays).

Arrays of this type include all the methods from ArrayBufferView

Methods and Fields

constructor Float64Array

View MDN documentation

(top)

Call type:

new Float64Array(arr, byteOffset, length)

Parameters

arr - The array or typed array to base this off, or an integer which is the array length

byteOffset - The byte offset in the ArrayBuffer (ONLY IF the first argument was an ArrayBuffer)

length - The length (ONLY IF the first argument was an ArrayBuffer)

Returns

A typed array

Description

Create a typed array based on the given input. Either an existing Array Buffer, an Integer as a Length, or a simple array. If an ArrayBufferView (eg. Uint8Array rather than ArrayBuffer) is given, it will be completely copied rather than referenced.

fs Class

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Methods and Fields

fs.pipe

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Call type:

fs.pipe(source, destination, options)

Parameters

source - The source file/stream that will send content.

destination - The destination file/stream that will receive content from the source.

options - An optional object { chunkSize : int=64, end : bool=true, complete : function }
chunkSize : The amount of data to pipe from source to destination at a time
complete : a function to call when the pipe activity is complete
end : call the 'end' function on the destination when the source is finished

Function Class

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This is the built-in class for Functions

Methods and Fields

function Function.apply

View MDN documentation

(top)

Call type:

function Function.apply(this, args)

Parameters

this - The value to use as the 'this' argument when executing the function

args - Optional Array of Arguments

Returns

The return value of executing this function

Description

This executes the function with the supplied 'this' argument and parameters

function Function.bind

View MDN documentation

(top)

Call type:

function Function.bind(this, params, ...)

Parameters

this - The value to use as the 'this' argument when executing the function

params, ... - Optional Default parameters that are prepended to the call

Returns

The 'bound' function

Description

This executes the function with the supplied 'this' argument and parameters

Examples

This function is used in the following places in Espruino's documentation

function Function.call

View MDN documentation

(top)

Call type:

function Function.call(this, params, ...)

Parameters

this - The value to use as the 'this' argument when executing the function

params, ... - Optional Parameters

Returns

The return value of executing this function

Description

This executes the function with the supplied 'this' argument and parameters

constructor Function

View MDN documentation

(top)

Call type:

new Function(args, ...)

Parameters

args, ... - Zero or more arguments (as strings), followed by a string representing the code to run

Returns

A Number object

Description

Creates a function

function Function.replaceWith

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Call type:

function Function.replaceWith(newFunc)

Parameters

newFunc - The new function to replace this function with

Description

This replaces the function with the one in the argument - while keeping the old function's scope. This allows inner functions to be edited, and is used when edit() is called on an inner function.

Graphics Class

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This class provides Graphics operations that can be applied to a surface.

Use Graphics.createXXX to create a graphics object that renders in the way you want. See the Graphics page for more information.

Note: On boards that contain an LCD, there is a built-in 'LCD' object of type Graphics. For instance to draw a line you'd type: LCD.drawLine(0,0,100,100)

Methods and Fields

function Graphics.asBMP

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Call type:

function Graphics.asBMP()

Returns

A String representing the Graphics as a Windows BMP file (or 'undefined' if not possible)

Description

Create a Windows BMP file from this Graphics instance, and return it as a String.

Note: This is only available in !devices with low flash memory with !'Original' Espruino boards

function Graphics.asImage

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Call type:

function Graphics.asImage()

Returns

An Image that can be used with Graphics.drawImage

Description

Return this Graphics object as an Image that can be used with Graphics.drawImage. Will return undefined if data can't be allocated for it.

Note: This is not available in devices with low flash memory

function Graphics.asURL

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Call type:

function Graphics.asURL()

Returns

A String representing the Graphics as a URL (or 'undefined' if not possible)

Description

Create a URL of the form data:image/bmp;base64,... that can be pasted into the browser.

The Espruino Web IDE can detect this data on the console and render the image inline automatically.

Note: This is only available in !devices with low flash memory with !'Original' Espruino boards

function Graphics.clear

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Call type:

function Graphics.clear(reset)

Parameters

reset - If true, resets the state of Graphics to the default (eg. Color, Font, etc) as if calling Graphics.reset

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Clear the LCD with the Background Color

Examples

This function is used in the following places in Espruino's documentation

function Graphics.clearRect

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Call type:

function Graphics.clearRect(x1, y1, x2, y2)

Parameters

x1 - The left X coordinate

y1 - The top Y coordinate

x2 - The right X coordinate

y2 - The bottom Y coordinate

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Fill a rectangular area in the Background Color

Note: This is not available in devices with low flash memory

Graphics.createArrayBuffer

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Call type:

Graphics.createArrayBuffer(width, height, bpp, options)

Parameters

width - Pixels wide

height - Pixels high

bpp - Number of bits per pixel

options - An object of other options. { zigzag : true/false(default), vertical_byte : true/false(default), msb : true/false(default), color_order: 'rgb'(default),'bgr',etc }
zigzag = whether to alternate the direction of scanlines for rows
vertical_byte = whether to align bits in a byte vertically or not
msb = when bits<8, store pixels msb first
interleavex = Pixels 0,2,4,etc are from the top half of the image, 1,3,5,etc from the bottom half. Used for P3 LED panels.
color_order = re-orders the colour values that are supplied via setColor

Returns

The new Graphics object

Description

Create a Graphics object that renders to an Array Buffer. This will have a field called 'buffer' that can get used to get at the buffer itself

Examples

This function is used in the following places in Espruino's documentation

Graphics.createCallback

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Call type:

Graphics.createCallback(width, height, bpp, callback)

Parameters

width - Pixels wide

height - Pixels high

bpp - Number of bits per pixel

callback - A function of the form function(x,y,col) that is called whenever a pixel needs to be drawn, or an object with: {setPixel:function(x,y,col),fillRect:function(x1,y1,x2,y2,col)}. All arguments are already bounds checked.

Returns

The new Graphics object

Description

Create a Graphics object that renders by calling a JavaScript callback function to draw pixels

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

Graphics.createImage

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Call type:

Graphics.createImage(str)

Parameters

str - A String containing a newline-separated image - space is 0, anything else is 1

Returns

An Image object that can be used with Graphics.drawImage

Description

Create a simple Black and White image for use with Graphics.drawImage.

Use as follows:

var img = Graphics.createImage(`
XXXXXXXXX
X       X
X   X   X
X   X   X
X       X
XXXXXXXXX
`);
g.drawImage(img, x,y);

If the characters at the beginning and end of the string are newlines, they will be ignored. Spaces are treated as 0, and any other character is a 1

Note: This is only available in !devices with low flash memory with !'Original' Espruino boards

function Graphics.drawCircle

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Call type:

function Graphics.drawCircle(x, y, rad)

Parameters

x - The X axis

y - The Y axis

rad - The circle radius

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Draw an unfilled circle 1px wide in the Foreground Color

Note: This is not available in devices with low flash memory

function Graphics.drawEllipse

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Call type:

function Graphics.drawEllipse(x1, y1, x2, y2)

Parameters

x1 - The left X coordinate

y1 - The top Y coordinate

x2 - The right X coordinate

y2 - The bottom Y coordinate

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Draw an ellipse in the Foreground Color

Note: This is not available in devices with low flash memory

function Graphics.drawImage

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Call type:

function Graphics.drawImage(image, x, y, options)

Parameters

image - An image to draw, either a String or an Object (see below)

x - The X offset to draw the image

y - The Y offset to draw the image

options - options for scaling,rotation,etc (see below)

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Image can be:

Draw an image at the specified position.

If options is supplied, drawImage will allow images to be rendered at any scale or angle. If options.rotate is set it will center images at x,y. options must be an object of the form:

{
  rotate : float, // the amount to rotate the image in radians (default 0)
  scale : float, // the amount to scale the image in radians (default 1)
}

function Graphics.drawLine

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Call type:

function Graphics.drawLine(x1, y1, x2, y2)

Parameters

x1 - The left

y1 - The top

x2 - The right

y2 - The bottom

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Draw a line between x1,y1 and x2,y2 in the current foreground color

Examples

This function is used in the following places in Espruino's documentation

function Graphics.drawPoly

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Call type:

function Graphics.drawPoly(poly, closed)

Parameters

poly - An array of vertices, of the form [x1,y1,x2,y2,x3,y3,etc]

closed - Draw another line between the last element of the array and the first

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Draw a polyline (lines between each of the points in poly) in the current foreground color

Note: This is not available in devices with low flash memory

function Graphics.drawRect

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Call type:

function Graphics.drawRect(x1, y1, x2, y2)

Parameters

x1 - The left X coordinate

y1 - The top Y coordinate

x2 - The right X coordinate

y2 - The bottom Y coordinate

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Draw an unfilled rectangle 1px wide in the Foreground Color

function Graphics.drawString

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Call type:

function Graphics.drawString(str, x, y, solid)

Parameters

str - The string

x - The X position of the leftmost pixel

y - The Y position of the topmost pixel

solid - For bitmap fonts, should empty pixels be filled with the background color?

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Draw a string of text in the current font

Examples

This function is used in the following places in Espruino's documentation

function Graphics.dump

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Call type:

function Graphics.dump()

Description

Output this image as a bitmap URL. The Espruino Web IDE can detect the data on the console and render the image inline automatically.

This is identical to console.log(g.asURL()) - it is just a convenient function for easy debugging.

Note: This is only available in !devices with low flash memory with !'Original' Espruino boards

function Graphics.fillCircle

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Call type:

function Graphics.fillCircle(x, y, rad)

Parameters

x - The X axis

y - The Y axis

rad - The circle radius

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Draw a filled circle in the Foreground Color

Note: This is not available in devices with low flash memory

function Graphics.fillEllipse

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Call type:

function Graphics.fillEllipse(x1, y1, x2, y2)

Parameters

x1 - The left X coordinate

y1 - The top Y coordinate

x2 - The right X coordinate

y2 - The bottom Y coordinate

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Draw a filled ellipse in the Foreground Color

Note: This is not available in devices with low flash memory

function Graphics.fillPoly

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Call type:

function Graphics.fillPoly(poly)

Parameters

poly - An array of vertices, of the form [x1,y1,x2,y2,x3,y3,etc]

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Draw a filled polygon in the current foreground color

Note: This is not available in devices with low flash memory

function Graphics.fillRect

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Call type:

function Graphics.fillRect(x1, y1, x2, y2)

Parameters

x1 - The left X coordinate

y1 - The top Y coordinate

x2 - The right X coordinate

y2 - The bottom Y coordinate

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Fill a rectangular area in the Foreground Color

function Graphics.getBgColor

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Call type:

function Graphics.getBgColor()

Returns

The integer value of the colour

Description

Get the background color to use for subsequent drawing operations

function Graphics.getColor

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Call type:

function Graphics.getColor()

Returns

The integer value of the colour

Description

Get the color to use for subsequent drawing operations

function Graphics.getFont

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Call type:

function Graphics.getFont()

Returns

Get the name of the current font

Description

Get the font by name - can be saved and used with Graphics.setFont

Note: This is not available in devices with low flash memory

function Graphics.getFontHeight

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Call type:

function Graphics.getFontHeight()

Returns

The height in pixels of the current font

Description

Return the height in pixels of the current font

Note: This is not available in devices with low flash memory

function Graphics.getFonts

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Call type:

function Graphics.getFonts()

Returns

And array of font names

Description

Return an array of all fonts currently in the Graphics library.

Note: Vector fonts are specified as Vector# where # is the font height. As there are effectively infinite fonts, just Vector is included in the list.

Note: This is not available in devices with low flash memory

function Graphics.getHeight

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Call type:

function Graphics.getHeight()

Returns

The height of the LCD

Description

The height of the LCD

Graphics.getInstance

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Call type:

Graphics.getInstance()

Returns

An instance of Graphics or undefined

Description

On devices like Pixl.js or HYSTM boards that contain a built-in display this will return an instance of the graphics class that can be used to access that display.

Internally, this is stored as a member called gfx inside the 'hiddenRoot'.

function Graphics.getModified

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Call type:

function Graphics.getModified(reset)

Parameters

reset - Whether to reset the modified area or not

Returns

An object {x1,y1,x2,y2} containing the modified area, or undefined if not modified

Description

Return the area of the Graphics canvas that has been modified, and optionally clear the modified area to 0.

For instance if g.setPixel(10,20) was called, this would return {x1:10, y1:20, x2:10, y2:20}

Note: This is not available in devices with low flash memory

function Graphics.getPixel

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Call type:

function Graphics.getPixel(x, y)

Parameters

x - The left

y - The top

Returns

The color

Description

Get a pixel's color

function Graphics.getWidth

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Call type:

function Graphics.getWidth()

Returns

The width of the LCD

Description

The width of the LCD

function Graphics.lineTo

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Call type:

function Graphics.lineTo(x, y)

Parameters

x - X value

y - Y value

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Draw a line from the last position of lineTo or moveTo to this position

function Graphics.moveTo

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Call type:

function Graphics.moveTo(x, y)

Parameters

x - X value

y - Y value

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Move the cursor to a position - see lineTo

function Graphics.quadraticBezier

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Call type:

function Graphics.quadraticBezier(arr, options)

Parameters

arr - An array of three vertices, six enties in form of [x0,y0,x1,y1,x2,y2]

options - number of points to calulate

Returns

Array with calculated points

Description

Calculate the square area under a Bezier curve.

x0,y0: start point x1,y1: control point y2,y2: end point

Max 10 points without start point.

Note: This is only available in !devices with low flash memory with !'Original' Espruino boards

function Graphics.reset

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Call type:

function Graphics.reset()

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Reset the state of Graphics to the defaults (eg. Color, Font, etc) that would have been used when Graphics was initialised.

function Graphics.scroll

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Call type:

function Graphics.scroll(x, y)

Parameters

x - X direction. >0 = to right

y - Y direction. >0 = down

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Scroll the contents of this graphics in a certain direction. The remaining area is filled with the background color.

Note: This uses repeated pixel reads and writes, so will not work on platforms that don't support pixel reads.

Note: This is only available in !devices with low flash memory with !'Original' Espruino boards

function Graphics.setBgColor

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Call type:

function Graphics.setBgColor(r, g, b)

Parameters

r - Red (between 0 and 1) OR an integer representing the color in the current bit depth and color order OR a hexidecimal color string of the form '#012345'

g - Green (between 0 and 1)

b - Blue (between 0 and 1)

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Set the background color to use for subsequent drawing operations.

See Graphics.setColor for more information on the mapping of r, g, and b to pixel values.

Note: On devices with low flash memory, r must be an integer representing the color in the current bit depth. It cannot be a floating point value, and g and b are ignored.

function Graphics.setClipRect

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Call type:

function Graphics.setClipRect(x1, y1, x2, y2)

Parameters

x1 - Top left X coordinate

y1 - Top left Y coordinate

x2 - Bottom right X coordinate

y2 - Bottom right Y coordinate

Returns

The instance of Graphics this was called on, to allow call chaining

Description

This sets the 'clip rect' that subsequent drawing operations are clipped to sit between.

These values are inclusive - eg g.setClipRect(1,0,5,0) will ensure that only pixel rows 1,2,3,4,5 are touched on column 0.

Note: For maximum flexibility, the values here are not range checked. For normal use, unsure X and Y are between 0 and getWidth/getHeight.

Note: This is not available in devices with low flash memory

function Graphics.setColor

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Call type:

function Graphics.setColor(r, g, b)

Parameters

r - Red (between 0 and 1) OR an integer representing the color in the current bit depth and color order OR a hexidecimal color string of the form '#012345'

g - Green (between 0 and 1)

b - Blue (between 0 and 1)

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Set the color to use for subsequent drawing operations.

If just r is specified as an integer, the numeric value will be written directly into a pixel. eg. On a 24 bit Graphics instance you set bright blue with either g.setColor(0,0,1) or g.setColor(0x0000FF).

A good shortcut to ensure you get white on all platforms is to use g.setColor(-1)

The mapping is as follows:

If you specified color_order when creating the Graphics instance, r,g and b will be swapped as you specified.

Note: On devices with low flash memory, r must be an integer representing the color in the current bit depth. It cannot be a floating point value, and g and b are ignored.

Examples

This function is used in the following places in Espruino's documentation

function Graphics.setFont

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Call type:

function Graphics.setFont(name, size)

Parameters

name - The name of the font to use (if undefined, the standard 4x6 font will be used)

size - The size of the font (or undefined)

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Set the font by name, eg "4x6", or "Vector12".

For bitmap fonts you can also specify a size multiplier, for example g.setFont("4x6",2) will double the size of the standard 4x6 bitmap font to 8x12.

Note: This is not available in devices with low flash memory

function Graphics.setFontAlign

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Call type:

function Graphics.setFontAlign(x, y, rotation)

Parameters

x - X alignment. -1=left (default), 0=center, 1=right

y - Y alignment. -1=top (default), 0=center, 1=bottom

rotation - Rotation of the text. 0=normal, 1=90 degrees clockwise, 2=180, 3=270

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Set the alignment for subsequent calls to drawString

Note: This is not available in devices with low flash memory

function Graphics.setFontBitmap

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Call type:

function Graphics.setFontBitmap()

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Make subsequent calls to drawString use the built-in 4x6 pixel bitmapped Font

It is recommended that you use Graphics.setFont("4x6") for more flexibility.

function Graphics.setFontCustom

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Call type:

function Graphics.setFontCustom(bitmap, firstChar, width, height)

Parameters

bitmap - A column-first, MSB-first, 1bpp bitmap containing the font bitmap

firstChar - The first character in the font - usually 32 (space)

width - The width of each character in the font. Either an integer, or a string where each character represents the width

height - The height as an integer (max 255). Bits 8-15 represent the scale factor (eg. 2<<8 is twice the size)

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Make subsequent calls to drawString use a Custom Font of the given height. See the Fonts page for more information about custom fonts and how to create them.

function Graphics.setFontVector

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Call type:

function Graphics.setFontVector(size)

Parameters

size - The height of the font, as an integer

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Make subsequent calls to drawString use a Vector Font of the given height.

It is recommended that you use Graphics.setFont("Vector", size) for more flexibility.

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

function Graphics.setPixel

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Call type:

function Graphics.setPixel(x, y, col)

Parameters

x - The left

y - The top

col - The color (if undefined, the foreground color is useD)

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Set a pixel's color

function Graphics.setRotation

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Call type:

function Graphics.setRotation(rotation, reflect)

Parameters

rotation - The clockwise rotation. 0 for no rotation, 1 for 90 degrees, 2 for 180, 3 for 270

reflect - Whether to reflect the image

Returns

The instance of Graphics this was called on, to allow call chaining

Description

Set the current rotation of the graphics device.

function Graphics.stringWidth

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Call type:

function Graphics.stringWidth(str)

Parameters

str - The string

Returns

The length of the string in pixels

Description

Return the size in pixels of a string of text in the current font

function Graphics.toColor

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Call type:

function Graphics.toColor(r, g, b)

Parameters

r - Red (between 0 and 1) OR an integer representing the color in the current bit depth and color order OR a hexidecimal color string of the form '#012345'

g - Green (between 0 and 1)

b - Blue (between 0 and 1)

Returns

The color index represented by the arguments

Description

Work out the color value to be used in the current bit depth based on the arguments.

This is used internally by setColor and setBgColor

// 1 bit
g.toColor(1,1,1) => 1
// 16 bit
g.toColor(1,0,0) => 0xF800

Note: This is not available in devices with low flash memory

heatshrink Library

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Simple library for compression/decompression using heatshrink, an LZSS compression tool.

Espruino uses heatshrink internally to compress RAM down to fit in Flash memory when save() is used. This just exposes that functionality.

Functions here take and return buffers of data. There is no support for streaming, so both the compressed and decompressed data must be able to fit in memory at the same time.

Methods and Fields

heatshrink.compress

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Call type:

require("heatshrink").compress(data)

Parameters

data - The data to compress

Returns

Returns the result as an ArrayBuffer

heatshrink.decompress

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Call type:

require("heatshrink").decompress(data)

Parameters

data - The data to decompress

Returns

Returns the result as an ArrayBuffer

I2C Class

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This class allows use of the built-in I2C ports. Currently it allows I2C Master mode only.

All addresses are in 7 bit format. If you have an 8 bit address then you need to shift it one bit to the right.

Instances

Methods and Fields

I2C.find

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Call type:

I2C.find(pin)

Parameters

pin - A pin to search with

Returns

An object of type I2C, or undefined if one couldn't be found.

Description

Try and find an I2C hardware device that will work on this pin (eg. I2C1)

May return undefined if no device can be found.

constructor I2C

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Call type:

new I2C()

Description

Create a software I2C port. This has limited functionality (no baud rate), but it can work on any pins.

Use I2C.setup to configure this port.

function I2C.readFrom

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Call type:

function I2C.readFrom(address, quantity)

Parameters

address - The 7 bit address of the device to request bytes from, or an object of the form {address:12, stop:false} to send this data without a STOP signal.

quantity - The number of bytes to request

Returns

The data that was returned - as a Uint8Array

Description

Request bytes from the given slave device, and return them as a Uint8Array (packed array of bytes). This is like using Arduino Wire's requestFrom, available and read functions. Sends a STOP

function I2C.setup

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Call type:

function I2C.setup(options)

Parameters

options - An optional structure containing extra information on initialising the I2C port
{scl:pin, sda:pin, bitrate:100000}
You can find out which pins to use by looking at your board's reference page and searching for pins with the I2C marker. Note that 400kHz is the maximum bitrate for most parts.

Description

Set up this I2C port

If not specified in options, the default pins are used (usually the lowest numbered pins on the lowest port that supports this peripheral)

Examples

This function is used in the following places in Espruino's documentation

function I2C.writeTo

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Call type:

function I2C.writeTo(address, data, ...)

Parameters

address - The 7 bit address of the device to transmit to, or an object of the form {address:12, stop:false} to send this data without a STOP signal.

data, ... - One or more items to write. May be ints, strings, arrays, or special objects (see E.toUint8Array for more info).

Description

Transmit to the slave device with the given address. This is like Arduino's beginTransmission, write, and endTransmission rolled up into one.

Int16Array Class

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This is the built-in JavaScript class for a typed array of 16 bit signed integers.

Instantiate this in order to efficiently store arrays of data (Espruino's normal arrays store data in a map, which is inefficient for non-sparse arrays).

Arrays of this type include all the methods from ArrayBufferView

Methods and Fields

constructor Int16Array

View MDN documentation

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Call type:

new Int16Array(arr, byteOffset, length)

Parameters

arr - The array or typed array to base this off, or an integer which is the array length

byteOffset - The byte offset in the ArrayBuffer (ONLY IF the first argument was an ArrayBuffer)

length - The length (ONLY IF the first argument was an ArrayBuffer)

Returns

A typed array

Description

Create a typed array based on the given input. Either an existing Array Buffer, an Integer as a Length, or a simple array. If an ArrayBufferView (eg. Uint8Array rather than ArrayBuffer) is given, it will be completely copied rather than referenced.

Int32Array Class

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This is the built-in JavaScript class for a typed array of 32 bit signed integers.

Instantiate this in order to efficiently store arrays of data (Espruino's normal arrays store data in a map, which is inefficient for non-sparse arrays).

Arrays of this type include all the methods from ArrayBufferView

Methods and Fields

constructor Int32Array

View MDN documentation

(top)

Call type:

new Int32Array(arr, byteOffset, length)

Parameters

arr - The array or typed array to base this off, or an integer which is the array length

byteOffset - The byte offset in the ArrayBuffer (ONLY IF the first argument was an ArrayBuffer)

length - The length (ONLY IF the first argument was an ArrayBuffer)

Returns

A typed array

Description

Create a typed array based on the given input. Either an existing Array Buffer, an Integer as a Length, or a simple array. If an ArrayBufferView (eg. Uint8Array rather than ArrayBuffer) is given, it will be completely copied rather than referenced.

Int8Array Class

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This is the built-in JavaScript class for a typed array of 8 bit signed integers.

Instantiate this in order to efficiently store arrays of data (Espruino's normal arrays store data in a map, which is inefficient for non-sparse arrays).

Arrays of this type include all the methods from ArrayBufferView

Methods and Fields

constructor Int8Array

View MDN documentation

(top)

Call type:

new Int8Array(arr, byteOffset, length)

Parameters

arr - The array or typed array to base this off, or an integer which is the array length

byteOffset - The byte offset in the ArrayBuffer (ONLY IF the first argument was an ArrayBuffer)

length - The length (ONLY IF the first argument was an ArrayBuffer)

Returns

A typed array

Description

Create a typed array based on the given input. Either an existing Array Buffer, an Integer as a Length, or a simple array. If an ArrayBufferView (eg. Uint8Array rather than ArrayBuffer) is given, it will be completely copied rather than referenced.

InternalError Class

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The base class for internal errors

Methods and Fields

constructor InternalError

View MDN documentation

(top)

Call type:

new InternalError(message)

Parameters

message - An optional message string

Returns

An InternalError object

Description

Creates an InternalError object

function InternalError.toString

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Call type:

function InternalError.toString()

Returns

A String

JSON Class

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An Object that handles conversion to and from the JSON data interchange format

Methods and Fields

JSON.parse

View MDN documentation

(top)

Call type:

JSON.parse(string)

Parameters

string - A JSON string

Returns

The JavaScript object created by parsing the data string

Description

Parse the given JSON string into a JavaScript object

NOTE: This implementation uses eval() internally, and as such it is unsafe as it can allow arbitrary JS commands to be executed.

Examples

This function is used in the following places in Espruino's documentation

JSON.stringify

View MDN documentation

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Call type:

JSON.stringify(data, replacer, space)

Parameters

data - The data to be converted to a JSON string

replacer - This value is ignored

space - The number of spaces to use for padding, a string, or null/undefined for no whitespace

Returns

A JSON string

Description

Convert the given object into a JSON string which can subsequently be parsed with JSON.parse or eval.

Note: This differs from JavaScript's standard JSON.stringify in that:

Examples

This function is used in the following places in Espruino's documentation

Math Class

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This is a standard JavaScript class that contains useful Maths routines

Methods and Fields

Math.abs

View MDN documentation

(top)

Call type:

Math.abs(x)

Parameters

x - A floating point value

Returns

The absolute value of x (eg, Math.abs(2)==2, but also Math.abs(-2)==2)

Examples

This function is used in the following places in Espruino's documentation

Math.acos

View MDN documentation

(top)

Call type:

Math.acos(x)

Parameters

x - The value to get the arc cosine of

Returns

The arc cosine of x, between 0 and PI

Math.asin

View MDN documentation

(top)

Call type:

Math.asin(x)

Parameters

x - The value to get the arc sine of

Returns

The arc sine of x, between -PI/2 and PI/2

Math.atan

View MDN documentation

(top)

Call type:

Math.atan(x)

Parameters

x - The value to get the arc tangent of

Returns

The arc tangent of x, between -PI/2 and PI/2

Math.atan2

View MDN documentation

(top)

Call type:

Math.atan2(y, x)

Parameters

y - The Y-part of the angle to get the arc tangent of

x - The X-part of the angle to get the arc tangent of

Returns

The arctangent of Y/X, between -PI and PI

Math.ceil

View MDN documentation

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Call type:

Math.ceil(x)

Parameters

x - The value to round up

Returns

x, rounded upwards to the nearest integer

Math.clip

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Call type:

Math.clip(x, min, max)

Parameters

x - A floating point value to clip

min - The smallest the value should be

max - The largest the value should be

Returns

The value of x, clipped so as not to be below min or above max.

Description

DEPRECATED - Please use E.clip() instead. Clip a number to be between min and max (inclusive)

Note: This is not available in devices with low flash memory

Math.cos

View MDN documentation

(top)

Call type:

Math.cos(theta)

Parameters

theta - The angle to get the cosine of

Returns

The cosine of theta

Examples

This function is used in the following places in Espruino's documentation

Math.E

View MDN documentation

(top)

Call type:

Math.E

Returns

The value of E - 2.718281828459045

Math.exp

View MDN documentation

(top)

Call type:

Math.exp(x)

Parameters

x - The value raise E to the power of

Returns

E^x

Math.floor

View MDN documentation

(top)

Call type:

Math.floor(x)

Parameters

x - The value to round down

Returns

x, rounded downwards to the nearest integer

Examples

This function is used in the following places in Espruino's documentation

Math.LN10

View MDN documentation

(top)

Call type:

Math.LN10

Returns

The natural logarithm of 10 - 2.302585092994046

Math.LN2

View MDN documentation

(top)

Call type:

Math.LN2

Returns

The natural logarithm of 2 - 0.6931471805599453

Math.log

View MDN documentation

(top)

Call type:

Math.log(x)

Parameters

x - The value to take the logarithm (base E) root of

Returns

The log (base E) of x

Examples

This function is used in the following places in Espruino's documentation

Math.LOG10E

View MDN documentation

(top)

Call type:

Math.LOG10E

Returns

The base 10 logarithm of e - 0.4342944819032518

Math.LOG2E

View MDN documentation

(top)

Call type:

Math.LOG2E

Returns

The base 2 logarithm of e - 1.4426950408889634

Math.max

View MDN documentation

(top)

Call type:

Math.max(args, ...)

Parameters

args, ... - Floating point values to clip

Returns

The maximum of the supplied values

Description

Find the maximum of a series of numbers

Examples

This function is used in the following places in Espruino's documentation

Math.min

View MDN documentation

(top)

Call type:

Math.min(args, ...)

Parameters

args, ... - Floating point values to clip

Returns

The minimum of the supplied values

Description

Find the minimum of a series of numbers

Examples

This function is used in the following places in Espruino's documentation

Math.PI

View MDN documentation

(top)

Call type:

Math.PI

Returns

The value of PI - 3.141592653589793

Math.pow

View MDN documentation

(top)

Call type:

Math.pow(x, y)

Parameters

x - The value to raise to the power

y - The power x should be raised to

Returns

x raised to the power y (x^y)

Math.random

View MDN documentation

(top)

Call type:

Math.random()

Returns

A random number between 0 and 1

Examples

This function is used in the following places in Espruino's documentation

Math.round

View MDN documentation

(top)

Call type:

Math.round(x)

Parameters

x - The value to round

Returns

x, rounded to the nearest integer

Examples

This function is used in the following places in Espruino's documentation

Math.sin

View MDN documentation

(top)

Call type:

Math.sin(theta)

Parameters

theta - The angle to get the sine of

Returns

The sine of theta

Examples

This function is used in the following places in Espruino's documentation

Math.sqrt

View MDN documentation

(top)

Call type:

Math.sqrt(x)

Parameters

x - The value to take the square root of

Returns

The square root of x

Examples

This function is used in the following places in Espruino's documentation

Math.SQRT1_2

View MDN documentation

(top)

Call type:

Math.SQRT1_2

Returns

The square root of 1/2 - 0.7071067811865476

Math.SQRT2

View MDN documentation

(top)

Call type:

Math.SQRT2

Returns

The square root of 2 - 1.4142135623730951

Math.tan

View MDN documentation

(top)

Call type:

Math.tan(theta)

Parameters

theta - The angle to get the tangent of

Returns

The tangent of theta

Math.wrap

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Call type:

Math.wrap(x, max)

Parameters

x - A floating point value to wrap

max - The largest the value should be

Returns

The value of x, wrapped so as not to be below min or above max.

Description

DEPRECATED - This is not part of standard JavaScript libraries

Wrap a number around if it is less than 0 or greater than or equal to max. For instance you might do: Math.wrap(angleInDegrees, 360)

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

Modules Class

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Built-in class that caches the modules used by the require command

Methods and Fields

Modules.addCached

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Call type:

Modules.addCached(id, sourcecode)

Parameters

id - The module name to add

sourcecode - The module's sourcecode

Description

Add the given module to the cache

Examples

This function is used in the following places in Espruino's documentation

Modules.getCached

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Call type:

Modules.getCached()

Returns

An array of module names

Description

Return an array of module names that have been cached

Modules.removeAllCached

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Call type:

Modules.removeAllCached()

Description

Remove all cached modules

Modules.removeCached

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Call type:

Modules.removeCached(id)

Parameters

id - The module name to remove

Description

Remove the given module from the list of cached modules

NRF Class

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The NRF class is for controlling functionality of the Nordic nRF51/nRF52 chips.

Most functionality is related to Bluetooth Low Energy, however there are also some functions related to NFC that apply to NRF52-based devices.

Methods and Fields

event NRF.characteristicsDiscover

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Call type:

NRF.on('characteristicsDiscover', function() { ... });

Description

Called with discovered characteristics when discovery is finished

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q) and ESP32 boards

event NRF.connect

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Call type:

NRF.on('connect', function(addr) { ... });

Parameters

addr - The address of the device that has connected

Description

Called when a host device connects to Espruino. The first argument contains the address.

NRF.connect

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Call type:

NRF.connect(mac, options)

Parameters

mac - The MAC address to connect to

options - (Espruino-specific) An object of connection options (see BluetoothRemoteGATTServer.connect for full details)

Returns

A Promise that is resolved (or rejected) when the connection is complete

Description

Connect to a BLE device by MAC address. Returns a promise, the argument of which is the BluetoothRemoteGATTServer connection.

NRF.connect("aa:bb:cc:dd:ee").then(function(server) {
  // ...
});

This has the same effect as calling BluetoothDevice.gatt.connect on a BluetoothDevice requested using NRF.requestDevice. It just allows you to specify the address directly (without having to scan).

You can use it as follows - this would connect to another Puck device and turn its LED on:

var gatt;
NRF.connect("aa:bb:cc:dd:ee random").then(function(g) {
  gatt = g;
  return gatt.getPrimaryService("6e400001-b5a3-f393-e0a9-e50e24dcca9e");
}).then(function(service) {
  return service.getCharacteristic("6e400002-b5a3-f393-e0a9-e50e24dcca9e");
}).then(function(characteristic) {
  return characteristic.writeValue("LED1.set()\n");
}).then(function() {
  gatt.disconnect();
  console.log("Done!");
});

Note: Espruino Bluetooth devices use a type of BLE address known as 'random static', which is different to a 'public' address. To connect to an Espruino device you'll need to use an address string of the form "aa:bb:cc:dd:ee random" rather than just "aa:bb:cc:dd:ee". If you scan for devices with NRF.findDevices/NRF.setScan then addresses are already reported in the correct format.

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q) and ESP32 boards

event NRF.disconnect

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Call type:

NRF.on('disconnect', function(reason) { ... });

Parameters

reason - The reason code reported back by the BLE stack - see Nordic's ble_hci.h file for more information

Description

Called when a host device disconnects from Espruino.

The most common reason is: 19 - REMOTE_USER_TERMINATED_CONNECTION 22 - LOCAL_HOST_TERMINATED_CONNECTION

Examples

This function is used in the following places in Espruino's documentation

NRF.disconnect

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Call type:

NRF.disconnect()

Description

If a device is connected to Espruino, disconnect from it.

Examples

This function is used in the following places in Espruino's documentation

NRF.filterDevices

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Call type:

NRF.filterDevices(devices, filters)

Parameters

devices - An array of BluetoothDevice objects, from NRF.findDevices or similar

filters - A list of filters (as would be passed to NRF.requestDevice) to filter devices by

Returns

An array of BluetoothDevice objects that match the given filters

Description

This function can be used to quickly filter through Bluetooth devices.

For instance if you wish to scan for multiple different types of device at the same time then you could use NRF.findDevices with all the filters you're interested in. When scanning is finished you can then use NRF.filterDevices to pick out just the devices of interest.

// the two types of device we're interested in
var filter1 = [{serviceData:{"fe95":{}}}];
var filter2 = [{namePrefix:"Pixl.js"}];
// the following filter will return both types of device
var allFilters = filter1.concat(filter2);
// now scan for both types of device, and filter them out afterwards
NRF.findDevices(function(devices) {
  var devices1 = NRF.filterDevices(devices, filter1);
  var devices2 = NRF.filterDevices(devices, filter2);
  // ...
}, {filters : allFilters});

NRF.findDevices

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Call type:

NRF.findDevices(callback, options)

Parameters

callback - The callback to call with received advertising packets (as BluetoothDevice), or undefined to stop

options - A time in milliseconds to scan for (defaults to 2000), Or an optional object {filters: ..., timeout : ..., active: bool} (as would be passed to NRF.requestDevice) to filter devices by

Description

Utility function to return a list of BLE devices detected in range. Behind the scenes, this uses NRF.setScan(...) and collates the results.

NRF.findDevices(function(devices) {
  console.log(devices);
}, 1000);

prints something like:

[
  BluetoothDevice {
    "id": "e7:e0:57:ad:36:a2 random",
    "rssi": -45,
    "services": [ "4567" ],
    "serviceData" : { "0123" : [ 1 ] },
    "manufacturerData" : [...],
    "data": new ArrayBuffer([ ... ]),
    "name": "Puck.js 36a2"
   },
  BluetoothDevice {
    "id": "c0:52:3f:50:42:c9 random",
    "rssi": -65,
    "data": new ArrayBuffer([ ... ]),
    "name": "Puck.js 8f57"
   }
 ]

For more information on the structure returned, see NRF.setScan.

If you want to scan only for specific devices you can replace the timeout with an object of the form {filters: ..., timeout : ..., active: bool} using the filters described in NRF.requestDevice. For example to search for devices with Espruino's manufacturerData:

NRF.findDevices(function(devices) {
  ...
}, {timeout : 2000, filters : [{ manufacturerData:{0x0590:{}} }] });

You could then use BluetoothDevice.gatt.connect(...) on the device returned to make a connection.

You can also use NRF.connect(...) on just the id string returned, which may be useful if you always want to connect to a specific device.

Note: Using findDevices turns the radio's receive mode on for 2000ms (or however long you specify). This can draw a lot of power (12mA or so), so you should use it sparingly or you can run your battery down quickly.

Note: The 'data' field contains the data of the last packet received. There may have been more packets. To get data for each packet individually use NRF.setScan instead.

NRF.getAddress

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Call type:

NRF.getAddress()

Returns

MAC address - a string of the form 'aa:bb:cc:dd:ee:ff'

Description

Get this device's default Bluetooth MAC address.

For Puck.js, the last 5 characters of this (eg. ee:ff) are used in the device's advertised Bluetooth name.

Examples

This function is used in the following places in Espruino's documentation

NRF.getAdvertisingData

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Call type:

NRF.getAdvertisingData(data, options)

Parameters

data - The data to advertise as an object

options - An optional object of options

Returns

An array containing the advertising data

Description

This is just like NRF.setAdvertising, except instead of advertising the data, it returns the packet that would be advertised as an array.

NRF.getBattery

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Call type:

NRF.getBattery()

Returns

Battery level in volts

Description

Get the battery level in volts (the voltage that the NRF chip is running off of).

This is the battery level of the device itself - it has nothing to with any device that might be connected.

NRF.getSecurityStatus

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Call type:

NRF.getSecurityStatus()

Returns

An object

Description

Return an object with information about the security state of the current peripheral connection:

{
  connected       // The connection is active (not disconnected).
  encrypted       // Communication on this link is encrypted.
  mitm_protected  // The encrypted communication is also protected against man-in-the-middle attacks.
  bonded          // The peer is bonded with us
}

If there is no active connection, {connected:false} will be returned.

See NRF.setSecurity for information about negotiating a secure connection.

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

event NRF.HID

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Call type:

NRF.on('HID', function() { ... });

Description

Called with a single byte value when Espruino is set up as a HID device and the computer it is connected to sends a HID report back to Espruino. This is usually used for handling indications such as the Caps Lock LED.

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

NRF.nfcAndroidApp

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Call type:

NRF.nfcAndroidApp(app)

Parameters

app - The unique identifier of the given Android App

Description

Enables NFC with a record that will launch the given android app.

For example:

NRF.nfcAndroidApp("no.nordicsemi.android.nrftoolbox")

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

event NRF.NFCoff

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Call type:

NRF.on('NFCoff', function() { ... });

Description

Called when an NFC field is no longer detected

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

event NRF.NFCon

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Call type:

NRF.on('NFCon', function() { ... });

Description

Called when an NFC field is detected

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

NRF.nfcPair

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Call type:

NRF.nfcPair(key)

Parameters

key - 16 byte out of band key

Description

Enables NFC and with an out of band 16 byte pairing key.

For example the following will enable out of band pairing on BLE such that the device will pair when you tap the phone against it:

var bleKey = [0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF, 0x99, 0x88, 0x77, 0x66, 0x55, 0x44, 0x33, 0x22, 0x11, 0x00];
NRF.on('security',s=>print("security",JSON.stringify(s)));
NRF.nfcPair(bleKey);
NRF.setSecurity({oob:bleKey, mitm:true});

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

NRF.nfcRaw

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Call type:

NRF.nfcRaw(payload)

Parameters

payload - The NFC NDEF message to deliver to the reader

Description

Enables NFC and starts advertising with Raw data. For example:

NRF.nfcRaw(new Uint8Array([193, 1, 0, 0, 0, 13, 85, 3, 101, 115, 112, 114, 117, 105, 110, 111, 46, 99, 111, 109]));
// same as NRF.nfcURL("http://espruino.com");

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

event NRF.NFCrx

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Call type:

NRF.on('NFCrx', function(arr) { ... });

Parameters

arr - An ArrayBuffer containign the received data

Description

When NFC is started with NRF.nfcStart, this is fired when NFC data is received. It doesn't get called if NFC is started with NRF.nfcURL or NRF.nfcRaw

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

NRF.nfcSend

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Call type:

NRF.nfcSend(payload)

Parameters

payload - Optional tx data

Description

Advanced NFC Functionality. If you just want to advertise a URL, use NRF.nfcURL instead.

Acknowledges the last frame and optionally transmits a response. If payload is an array, then a array.length byte nfc frame is sent. If payload is a int, then a 4bit ACK/NACK is sent. Note: nfcSend should always be called after an NFCrx event.

NRF.nfcSend(new Uint8Array([0x01, 0x02, ...]));
// or
NRF.nfcSend(0x0A);
// or
NRF.nfcSend();

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

NRF.nfcStart

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Call type:

NRF.nfcStart(payload)

Parameters

payload - Optional 7 byte UID

Returns

Internal tag memory (first 10 bytes of tag data)

Description

Advanced NFC Functionality. If you just want to advertise a URL, use NRF.nfcURL instead.

Enables NFC and starts advertising. NFCrx events will be fired when data is received.

NRF.nfcStart();

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

NRF.nfcStop

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Call type:

NRF.nfcStop()

Parameters

Description

Advanced NFC Functionality. If you just want to advertise a URL, use NRF.nfcURL instead.

Disables NFC.

NRF.nfcStop();

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

NRF.nfcURL

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Call type:

NRF.nfcURL(url)

Parameters

url - The URL string to expose on NFC, or undefined to disable NFC

Description

Enables NFC and starts advertising the given URL. For example:

NRF.nfcURL("http://espruino.com");

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

NRF.requestDevice

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Call type:

NRF.requestDevice(options)

Parameters

options - Options used to filter the device to use

Returns

A Promise that is resolved (or rejected) when the connection is complete

Description

Search for available devices matching the given filters. Since we have no UI here, Espruino will pick the FIRST device it finds, or it'll call catch.

options can have the following fields:

NOTE: timeout and active are not part of the Web Bluetooth standard.

The following filter types are implemented:

NRF.requestDevice({ filters: [{ namePrefix: 'Puck.js' }] }).then(function(device) { ... });
// or
NRF.requestDevice({ filters: [{ services: ['1823'] }] }).then(function(device) { ... });
// or
NRF.requestDevice({ filters: [{ manufacturerData:{0x0590:{}} }] }).then(function(device) { ... });

As a full example, to send data to another Puck.js to turn an LED on:

var gatt;
NRF.requestDevice({ filters: [{ namePrefix: 'Puck.js' }] }).then(function(device) {
  return device.gatt.connect();
}).then(function(g) {
  gatt = g;
  return gatt.getPrimaryService("6e400001-b5a3-f393-e0a9-e50e24dcca9e");
}).then(function(service) {
  return service.getCharacteristic("6e400002-b5a3-f393-e0a9-e50e24dcca9e");
}).then(function(characteristic) {
  return characteristic.writeValue("LED1.set()\n");
}).then(function() {
  gatt.disconnect();
  console.log("Done!");
});

Or slightly more concisely, using ES6 arrow functions:

var gatt;
NRF.requestDevice({ filters: [{ namePrefix: 'Puck.js' }]}).then(
  device => device.gatt.connect()).then(
  g => (gatt=g).getPrimaryService("6e400001-b5a3-f393-e0a9-e50e24dcca9e")).then(
  service => service.getCharacteristic("6e400002-b5a3-f393-e0a9-e50e24dcca9e")).then(
  characteristic => characteristic.writeValue("LED1.reset()\n")).then(
  () => { gatt.disconnect(); console.log("Done!"); } );

Note that you have to keep track of the gatt variable so that you can disconnect the Bluetooth connection when you're done.

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q) and ESP32 boards

NRF.restart

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Call type:

NRF.restart()

Description

Restart the Bluetooth softdevice (if there is currently a BLE connection, it will queue a restart to be done when the connection closes).

You shouldn't need to call this function in normal usage. However, Nordic's BLE softdevice has some settings that cannot be reset. For example there are only a certain number of unique UUIDs. Once these are all used the only option is to restart the softdevice to clear them all out.

event NRF.security

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Call type:

NRF.on('security', function(status) { ... });

Parameters

status - An object containing `{auth_status,bonded,lv4,kdist_own,kdist_peer}

Description

Contains updates on the security of the current Bluetooth link.

See Nordic's ble_gap_evt_auth_status_t structure for more information.

NRF.sendHIDReport

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Call type:

NRF.sendHIDReport(data, callback)

Parameters

data - Input report data as an array

callback - A callback function to be called when the data is sent

Description

Send a USB HID report. HID must first be enabled with NRF.setServices({}, {hid: hid_report})

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

Examples

This function is used in the following places in Espruino's documentation

event NRF.servicesDiscover

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Call type:

NRF.on('servicesDiscover', function() { ... });

Description

Called with discovered services when discovery is finished

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q) and ESP32 boards

NRF.setAddress

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Call type:

NRF.setAddress(addr)

Parameters

addr - The address to use (as a string)

Description

Set this device's default Bluetooth MAC address:

NRF.setAddress("ff:ee:dd:cc:bb:aa random");

Addresses take the form:

This may throw a INVALID_BLE_ADDR error if the upper two bits of the address don't match the address type.

To change the address, Espruino must restart the softdevice. It will only do so when it is disconnected from other devices.

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

NRF.setAdvertising

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Call type:

NRF.setAdvertising(data, options)

Parameters

data - The data to advertise as an object - see below for more info

options - An optional object of options

Description

Change the data that Espruino advertises.

Data can be of the form { UUID : data_as_byte_array }. The UUID should be a Bluetooth Service ID.

For example to return battery level at 95%, do:

NRF.setAdvertising({
  0x180F : [95]
});

Or you could report the current temperature:

setInterval(function() {
  NRF.setAdvertising({
    0x1809 : [Math.round(E.getTemperature())]
  });
}, 30000);

You can also supply the raw advertising data in an array. For example to advertise as an Eddystone beacon:

NRF.setAdvertising([0x03,  // Length of Service List
  0x03,  // Param: Service List
  0xAA, 0xFE,  // Eddystone ID
  0x13,  // Length of Service Data
  0x16,  // Service Data
  0xAA, 0xFE, // Eddystone ID
  0x10,  // Frame type: URL
  0xF8, // Power
  0x03, // https://
  'g','o','o','.','g','l','/','B','3','J','0','O','c'],
    {interval:100});

(However for Eddystone we'd advise that you use the Espruino Eddystone library)

Note: When specifying data as an array, certain advertising options such as discoverable and showName won't have any effect.

Note: The size of Bluetooth LE advertising packets is limited to 31 bytes. If you want to advertise more data, consider using an array for data (See below), or NRF.setScanResponse.

You can even specify an array of arrays or objects, in which case each advertising packet will be used in turn - for instance to make your device advertise battery level and its name as well as both Eddystone and iBeacon :

NRF.setAdvertising([
  {0x180F : [Puck.getBatteryPercentage()]}, // normal advertising, with battery %
  require("ble_ibeacon").get(...), // iBeacon
  require("ble_eddystone").get(...), // eddystone
], {interval:300});

options is an object, which can contain:

{
  name: "Hello" // The name of the device
  showName: true/false // include full name, or nothing
  discoverable: true/false // general discoverable, or limited - default is limited
  connectable: true/false // whether device is connectable - default is true
  scannable : true/false // whether device can be scanned for scan response packets - default is true
  interval: 600 // Advertising interval in msec, between 20 and 10000 (default is 375ms)
  manufacturer: 0x0590 // IF sending manufacturer data, this is the manufacturer ID
  manufacturerData: [...] // IF sending manufacturer data, this is an array of data
}

Setting connectable and scannable to false gives the lowest power consumption as the BLE radio doesn't have to listen after sending advertising.

NOTE: Non-connectable advertising can't have an advertising interval less than 100ms according to the BLE spec.

So for instance to set the name of Puck.js without advertising any other data you can just use the command:

NRF.setAdvertising({},{name:"Hello"});

You can also specify 'manufacturer data', which is another form of advertising data. We've registered the Manufacturer ID 0x0590 (as Pur3 Ltd) for use with Official Espruino devices - use it to advertise whatever data you'd like, but we'd recommend using JSON.

For example by not advertising a device name you can send up to 24 bytes of JSON on Espruino's manufacturer ID:

var data = {a:1,b:2};
NRF.setAdvertising({},{
  showName:false,
  manufacturer:0x0590,
  manufacturerData:JSON.stringify(data)
});

If you're using EspruinoHub then it will automatically decode this into the folling MQTT topics:

Note that you only have 24 characters available for JSON, so try to use the shortest field names possible and avoid floating point values that can be very long when converted to a String.

NRF.setConnectionInterval

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Call type:

NRF.setConnectionInterval(interval)

Parameters

interval - The connection interval to use (see below)

Description

When connected, Bluetooth LE devices communicate at a set interval. Lowering the interval (eg. more packets/second) means a lower delay when sending data, higher bandwidth, but also more power consumption.

By default, when connected as a peripheral Espruino automatically adjusts the connection interval. When connected it's as fast as possible (7.5ms) but when idle for over a minute it drops to 200ms. On continued activity (>1 BLE operation) the interval is raised to 7.5ms again.

The options for interval are:

This configuration is not remembered during a save() - you will have to re-set it via onInit.

Note: If connecting to another device (as Central), you can use an extra argument to NRF.connect or BluetoothRemoteGATTServer.connect to specify a connection interval.

Note: This overwrites any changes imposed by the deprecated NRF.setLowPowerConnection

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

NRF.setLowPowerConnection

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Call type:

NRF.setLowPowerConnection(lowPower)

Parameters

lowPower - Whether the connection is low power or not

Description

THIS IS DEPRECATED - please use NRF.setConnectionInterval for peripheral and NRF.connect(addr, options)/BluetoothRemoteGATTServer.connect(options) for central connections.

This sets the connection parameters - these affect the transfer speed and power usage when the device is connected.

When low power connection is enabled, transfers of data over Bluetooth will be very slow, however power usage while connected will be drastically decreased.

This will only take effect after the connection is disconnected and re-established.

NRF.setRSSIHandler

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Call type:

NRF.setRSSIHandler(callback)

Parameters

callback - The callback to call with the RSSI value, or undefined to stop

Description

Start/stop listening for RSSI values on the currently active connection (where This device is a peripheral and is being connected to by a 'central' device)

// Start scanning
NRF.setRSSIHandler(function(rssi) {
  console.log(rssi); // prints -85 (or similar)
});
// Stop Scanning
NRF.setRSSIHandler();

RSSI is the 'Received Signal Strength Indication' in dBm

NRF.setScan

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Call type:

NRF.setScan(callback, options)

Parameters

callback - The callback to call with received advertising packets, or undefined to stop

options - An optional object {filters: ...} (as would be passed to NRF.requestDevice) to filter devices by

Description

Start/stop listening for BLE advertising packets within range. Returns a BluetoothDevice for each advertsing packet. By default this is not an active scan, so Scan Response advertising data is not included (see below)

// Start scanning
packets=10;
NRF.setScan(function(d) {
  packets--;
  if (packets<=0)
    NRF.setScan(); // stop scanning
  else
    console.log(d); // print packet info
});

Each BluetoothDevice will look a bit like:

BluetoothDevice {
  "id": "aa:bb:cc:dd:ee:ff", // address
  "rssi": -89,               // signal strength
  "services": [ "128bit-uuid", ... ],     // zero or more service UUIDs
  "data": new Uint8Array([ ... ]).buffer, // ArrayBuffer of returned data
  "serviceData" : { "0123" : [ 1 ] }, // if service data is in 'data', it's extracted here
  "manufacturer" : 0x1234, // if manufacturer data is in 'data', the 16 bit manufacturer ID is extracted here
  "manufacturerData" : [...], // if manufacturer data is in 'data', the data is extracted here
  "name": "DeviceName"       // the advertised device name
 }

You can also supply a set of filters (as decribed in NRF.requestDevice) as a second argument, which will allow you to filter the devices you get a callback for. This helps to cut down on the time spent processing JavaScript code in areas with a lot of Bluetooth advertisements. For example to find only devices with the manufacturer data 0x0590 (Espruino's ID) you could do:

NRF.setScan(function(d) {
  console.log(d.manufacturerData);
}, { filters: [{ manufacturerData:{0x0590:{}} }] });

You can also specify active:true in the second argument to perform active scanning (this requests scan response packets) from any devices it finds.

Note: BLE advertising packets can arrive quickly - faster than you'll be able to print them to the console. It's best only to print a few, or to use a function like NRF.findDevices(..) which will collate a list of available devices.

Note: Using setScan turns the radio's receive mode on constantly. This can draw a lot of power (12mA or so), so you should use it sparingly or you can run your battery down quickly.

NRF.setScanResponse

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Call type:

NRF.setScanResponse(data)

Parameters

data - The data to for the scan response

Description

The raw scan response data should be supplied as an array. For example to return "Sample" for the device name:

NRF.setScanResponse([0x07,  // Length of Data
  0x09,  // Param: Complete Local Name
  'S', 'a', 'm', 'p', 'l', 'e']);

Note: NRF.setServices(..., {advertise:[ ... ]}) writes advertised services into the scan response - so you can't use both advertise and NRF.setServices or one will overwrite the other.

NRF.setSecurity

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Call type:

NRF.setSecurity(options)

Parameters

options - An object containing security-related options (see below)

Description

Sets the security options used when connecting/pairing. This applies to both central and peripheral mode.

NRF.setSecurity({
  display : bool  // default false, can this device display a passkey
                  // - sent via the `BluetoothDevice.passkey` event
  keyboard : bool // default false, can this device enter a passkey
                  // - request sent via the `BluetoothDevice.passkeyRequest` event
  bond : bool // default true, Perform bonding
  mitm : bool // default false, Man In The Middle protection
  lesc : bool // default false, LE Secure Connections
  passkey : // default "", or a 6 digit passkey to use
  oob : [0..15] // if specified, Out Of Band pairing is enabled and
                // the 16 byte pairing code supplied here is used
});

NOTE: Some combinations of arguments will cause an error. For example supplying a passkey without display:1 is not allowed. If display:1 is set you do not require a physical display, the user just needs to know the passkey you supplied.

For instance, to require pairing and to specify a passkey, use:

NRF.setSecurity({passkey:"123456", mitm:1, display:1});

However, while most devices will request a passkey for pairing at this point it is still possible for a device to connect without requiring one (eg. using the 'NRF Connect' app).

To force a passkey you need to protect each characteristic you define with NRF.setSecurity. For instance the following code will require that the passkey 123456 is entered before the characteristic 9d020002-bf5f-1d1a-b52a-fe52091d5b12 can be read.

NRF.setSecurity({passkey:"123456", mitm:1, display:1});
NRF.setServices({
  "9d020001-bf5f-1d1a-b52a-fe52091d5b12" : {
    "9d020002-bf5f-1d1a-b52a-fe52091d5b12" : {
      // readable always
      value : "Not Secret"
    },
    "9d020003-bf5f-1d1a-b52a-fe52091d5b12" : {
      // readable only once bonded
      value : "Secret",
      readable : true,
      security: {
        read: {
          mitm: true,
          encrypted: true
        }
      }
    },
    "9d020004-bf5f-1d1a-b52a-fe52091d5b12" : {
      // readable always
      // writable only once bonded
      value : "Readable",
      readable : true,
      writable : true,
      onWrite : function(evt) {
        console.log("Wrote ", evt.data);
      },
      security: {
        write: {
          mitm: true,
          encrypted: true
        }
      }
    }
  }
});

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

NRF.setServices

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Call type:

NRF.setServices(data, options)

Parameters

data - The service (and characteristics) to advertise

options - Optional object containing options

Description

Change the services and characteristics Espruino advertises.

If you want to change the value of a characteristic, you need to use NRF.updateServices() instead

To expose some information on Characteristic ABCD on service BCDE you could do:

NRF.setServices({
  0xBCDE : {
    0xABCD : {
      value : "Hello",
      readable : true
    }
  }
});

Or to allow the 3 LEDs to be controlled by writing numbers 0 to 7 to a characteristic, you can do the following. evt.data is an ArrayBuffer.

NRF.setServices({
  0xBCDE : {
    0xABCD : {
      writable : true,
      onWrite : function(evt) {
        digitalWrite([LED3,LED2,LED1], evt.data[0]);
      }
    }
  }
});

You can supply many different options:

NRF.setServices({
  0xBCDE : {
    0xABCD : {
      value : "Hello", // optional
      maxLen : 5, // optional (otherwise is length of initial value)
      broadcast : false, // optional, default is false
      readable : true,   // optional, default is false
      writable : true,   // optional, default is false
      notify : true,   // optional, default is false
      indicate : true,   // optional, default is false
      description: "My Characteristic",  // optional, default is null,
      security: { // optional - see NRF.setSecurity
        read: { // optional
          encrypted: false, // optional, default is false
          mitm: false, // optional, default is false
          lesc: false, // optional, default is false
          signed: false // optional, default is false
        },
        write: { // optional
          encrypted: true, // optional, default is false
          mitm: false, // optional, default is false
          lesc: false, // optional, default is false
          signed: false // optional, default is false
        }
      },
      onWrite : function(evt) { // optional
        console.log("Got ", evt.data); // an ArrayBuffer
      }
    }
    // more characteristics allowed
  }
  // more services allowed
});

Note: UUIDs can be integers between 0 and 0xFFFF, strings of the form "ABCD", or strings of the form "ABCDABCD-ABCD-ABCD-ABCD-ABCDABCDABCD"

options can be of the form:

NRF.setServices(undefined, {
  hid : new Uint8Array(...), // optional, default is undefined. Enable BLE HID support
  uart : true, // optional, default is true. Enable BLE UART support
  advertise: [ '180D' ] // optional, list of service UUIDs to advertise
});

To enable BLE HID, you must set hid to an array which is the BLE report descriptor. The easiest way to do this is to use the ble_hid_controls or ble_hid_keyboard modules.

Note: Just creating a service doesn't mean that the service will be advertised. It will only be available after a device connects. To advertise, specify the UUIDs you wish to advertise in the advertise field of the second options argument. For example this will create and advertise a heart rate service:

NRF.setServices({
  0x180D: { // heart_rate
    0x2A37: { // heart_rate_measurement
      notify: true,
      value : [0x06, heartrate],
    }
  }
}, { advertise: [ '180D' ] });

You may specify 128 bit UUIDs to advertise, however you may get a DATA_SIZE exception because there is insufficient space in the Bluetooth LE advertising packet for the 128 bit UART UUID as well as the UUID you specified. In this case you can add uart:false after the advertise element to disable the UART, however you then be unable to connect to Puck.js's console via Bluetooth.

If you absolutely require two or more 128 bit UUIDs then you will have to specify your own raw advertising data packets with NRF.setAdvertising

Note: The services on Espruino can only be modified when there is no device connected to it as it requires a restart of the Bluetooth stack. iOS devices will 'cache' the list of services so apps like NRF Connect may incorrectly display the old services even after you have modified them. To fix this, disable and re-enable Bluetooth on your iOS device, or use an Android device to run NRF Connect.

Note: Not all combinations of security configuration values are valid, the valid combinations are: encrypted, encrypted + mitm, lesc, signed, signed + mitm. See NRF.setSecurity for more information.

NRF.setTxPower

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Call type:

NRF.setTxPower(power)

Parameters

power - Transmit power. Accepted values are -40(nRF52 only), -30(nRF51 only), -20, -16, -12, -8, -4, 0, and 4 dBm. Others will give an error code.

Description

Set the BLE radio transmit power. The default TX power is 0 dBm.

NRF.setWhitelist

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Call type:

NRF.setWhitelist(whitelisting)

Parameters

whitelisting - Are we using a whitelist? (default false)

Description

If set to true, whenever a device bonds it will be added to the whitelist.

When set to false, the whitelist is cleared and newly bonded devices will not be added to the whitelist.

Note: This is remembered between reset()s but isn't remembered after power-on (you'll have to add it to onInit().

Note: This is only available in NRF52 devices (like Puck.js, Pixl.js and MDBT42Q)

NRF.sleep

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Call type:

NRF.sleep()

Description

Disable Bluetooth advertising and disconnect from any device that connected to Puck.js as a peripheral (this won't affect any devices that Puck.js initiated connections to).

This makes Puck.js undiscoverable, so it can't be connected to.

Use NRF.wake() to wake up and make Puck.js connectable again.

Examples

This function is used in the following places in Espruino's documentation

NRF.updateServices

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Call type:

NRF.updateServices(data)

Parameters

data - The service (and characteristics) to update

Description

Update values for the services and characteristics Espruino advertises. Only services and characteristics previously declared using NRF.setServices are affected.

To update the '0xABCD' characteristic in the '0xBCDE' service:

NRF.updateServices({
  0xBCDE : {
    0xABCD : {
      value : "World"
    }
  }
});

You can also use 128 bit UUIDs, for example "b7920001-3c1b-4b40-869f-3c0db9be80c6".

To define a service and characteristic and then notify connected clients of a change to it when a button is pressed:

NRF.setServices({
  0xBCDE : {
    0xABCD : {
      value : "Hello",
      maxLen : 20,
      notify: true
    }
  }
});
setWatch(function() {
  NRF.updateServices({
    0xBCDE : {
      0xABCD : {
        value : "World!",
        notify: true
      }
    }
  });
}, BTN, { repeat:true, edge:"rising", debounce: 50 });

This only works if the characteristic was created with notify: true using NRF.setServices, otherwise the characteristic will be updated but no notification will be sent.

Also note that maxLen was specified. If it wasn't then the maximum length of the characteristic would have been 5 - the length of "Hello".

To indicate (i.e. notify with ACK) connected clients of a change to the '0xABCD' characteristic in the '0xBCDE' service:

NRF.updateServices({
  0xBCDE : {
    0xABCD : {
      value : "World",
      indicate: true
    }
  }
});

This only works if the characteristic was created with indicate: true using NRF.setServices, otherwise the characteristic will be updated but no notification will be sent.

Note: See NRF.setServices for more information

NRF.wake

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Call type:

NRF.wake()

Description

Enable Bluetooth advertising (this is enabled by default), which allows other devices to discover and connect to Puck.js.

Use NRF.sleep() to disable advertising.

Number Class

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This is the built-in JavaScript class for numbers.

Methods and Fields

Number.MAX_VALUE

View MDN documentation

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Call type:

Number.MAX_VALUE

Returns

Maximum representable value

Number.MIN_VALUE

View MDN documentation

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Call type:

Number.MIN_VALUE

Returns

Smallest representable value

Number.NaN

View MDN documentation

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Call type:

Number.NaN

Returns

Not a Number

Number.NEGATIVE_INFINITY

View MDN documentation

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Call type:

Number.NEGATIVE_INFINITY

Returns

Negative Infinity (-1/0)

constructor Number

View MDN documentation

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Call type:

new Number(value, ...)

Parameters

value, ... - A single value to be converted to a number

Returns

A Number object

Description

Creates a number

Number.POSITIVE_INFINITY

View MDN documentation

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Call type:

Number.POSITIVE_INFINITY

Returns

Positive Infinity (1/0)

function Number.toFixed

View MDN documentation

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Call type:

function Number.toFixed(decimalPlaces)

Parameters

decimalPlaces - A number between 0 and 20 specifying the number of decimal digits after the decimal point

Returns

A string

Description

Format the number as a fixed point number

Examples

This function is used in the following places in Espruino's documentation

Object Class

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This is the built-in class for Objects

Methods and Fields

Object.assign

View MDN documentation

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Call type:

Object.assign(args, ...)

Parameters

args, ... - The target object, then any items objects to use as sources of keys

Returns

The target object

Description

Appends all keys and values in any subsequent objects to the first object

Note: Unlike the standard ES6 Object.assign, this will throw an exception if given raw strings, bools or numbers rather than objects.

function Object.clone

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Call type:

function Object.clone()

Returns

A copy of this Object

Description

Copy this object completely

Object.create

View MDN documentation

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Call type:

Object.create(proto, propertiesObject)

Parameters

proto - A prototype object

propertiesObject - An object containing properties. NOT IMPLEMENTED

Returns

A new object

Description

Creates a new object with the specified prototype object and properties. properties are currently unsupported.

Object.defineProperties

View MDN documentation

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Call type:

Object.defineProperties(obj, props)

Parameters

obj - An object

props - An object whose fields represent property names, and whose values are property descriptors.

Returns

The object, obj.

Description

Adds new properties to the Object. See Object.defineProperty for more information

Object.defineProperty

View MDN documentation

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Call type:

Object.defineProperty(obj, name, desc)

Parameters

obj - An object

name - The name of the property

desc - The property descriptor

Returns

The object, obj.

Description

Add a new property to the Object. 'Desc' is an object with the following fields:

Note: configurable, enumerable, writable, get, and set are not implemented and will be ignored.

function Object.emit

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Call type:

function Object.emit(event, args, ...)

Parameters

event - The name of the event, for instance 'data'

args, ... - Optional arguments

Description

Call the event listeners for this object, for instance http.emit('data', 'Foo'). See Node.js's EventEmitter.

Object.getOwnPropertyDescriptor

View MDN documentation

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Call type:

Object.getOwnPropertyDescriptor(obj, name)

Parameters

obj - The object

name - The name of the property

Returns

An object with a description of the property. The values of writable/enumerable/configurable may not be entirely correct due to Espruino's implementation.

Description

Get information on the given property in the object, or undefined

Object.getOwnPropertyNames

View MDN documentation

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Call type:

Object.getOwnPropertyNames(object)

Parameters

object - The Object to return a list of property names for

Returns

An array of the Object's own properties

Description

Returns an array of all properties (enumerable or not) found directly on a given object.

Object.getPrototypeOf

View MDN documentation

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Call type:

Object.getPrototypeOf(object)

Parameters

object - An object

Returns

The prototype

Description

Get the prototype of the given object - this is like writing object.__proto__ but is the 'proper' ES6 way of doing it

function Object.hasOwnProperty

View MDN documentation

(top)

Call type:

function Object.hasOwnProperty(name)

Parameters

name - The name of the property to search for

Returns

True if it exists, false if it doesn't

Description

Return true if the object (not its prototype) has the given property.

NOTE: This currently returns false-positives for built-in functions in prototypes

Object.keys

View MDN documentation

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Call type:

Object.keys(object)

Parameters

object - The object to return keys for

Returns

An array of strings - one for each key on the given object

Description

Return all enumerable keys of the given object

property Object.length

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Call type:

property Object.length

Returns

The length of the object

Description

Find the length of the object

constructor Object

View MDN documentation

(top)

Call type:

new Object(value)

Parameters

value - A single value to be converted to an object

Returns

An Object

Description

Creates an Object from the supplied argument

function Object.on

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Call type:

function Object.on(event, listener)

Parameters

event - The name of the event, for instance 'data'

listener - The listener to call when this event is received

Description

Register an event listener for this object, for instance http.on('data', function(d) {...}). See Node.js's EventEmitter.

Examples

This function is used in the following places in Espruino's documentation

function Object.removeAllListeners

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Call type:

function Object.removeAllListeners(event)

Parameters

event - The name of the event, for instance 'data'

Description

Removes all listeners, or those of the specified event.

Examples

This function is used in the following places in Espruino's documentation

function Object.removeListener

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Call type:

function Object.removeListener(event, listener)

Parameters

event - The name of the event, for instance 'data'

listener - The listener to remove

Description

Removes the specified event listener.

function foo(d) {
  console.log(d);
}
Serial1.on("data", foo);
Serial1.removeListener("data", foo);

Object.setPrototypeOf

View MDN documentation

(top)

Call type:

Object.setPrototypeOf(object, prototype)

Parameters

object - An object

prototype - The prototype to set on the object

Returns

The object passed in

Description

Set the prototype of the given object - this is like writing object.__proto__ = prototype but is the 'proper' ES6 way of doing it

function Object.toString

View MDN documentation

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Call type:

function Object.toString(radix)

Parameters

radix - If the object is an integer, the radix (between 2 and 36) to use. NOTE: Setting a radix does not work on floating point numbers.

Returns

A String representing the object

Description

Convert the Object to a string

Examples

This function is used in the following places in Espruino's documentation

function Object.valueOf

View MDN documentation

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Call type:

function Object.valueOf()

Returns

The primitive value of this object

Description

Returns the primitive value of this object.

OneWire Class

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This class provides a software-defined OneWire master. It is designed to be similar to Arduino's OneWire library.

Methods and Fields

constructor OneWire

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Call type:

new OneWire(pin)

Parameters

pin - The pin to implement OneWire on

Returns

A OneWire object

Description

Create a software OneWire implementation on the given pin

function OneWire.read

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Call type:

function OneWire.read(count)

Parameters

count - (optional) The amount of bytes to read

Returns

The byte that was read, or a Uint8Array if count was specified and >=0

Description

Read a byte

function OneWire.reset

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Call type:

function OneWire.reset()

Returns

True is a device was present (it held the bus low)

Description

Perform a reset cycle

function OneWire.search

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Call type:

function OneWire.search()

Returns

An array of devices that were found

Description

Search for devices

Examples

This function is used in the following places in Espruino's documentation

function OneWire.search

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Call type:

function OneWire.search(command)

Parameters

command - (Optional) command byte. If not specified (or zero), this defaults to 0xF0. This can could be set to 0xEC to perform a DS18B20 'Alarm Search Command'

Returns

An array of devices that were found

Description

Search for devices

Examples

This function is used in the following places in Espruino's documentation

function OneWire.select

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Call type:

function OneWire.select(rom)

Parameters

rom - The device to select (get this using OneWire.search())

Description

Select a ROM - always performs a reset first

function OneWire.skip

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Call type:

function OneWire.skip()

Description

Skip a ROM

function OneWire.write

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Call type:

function OneWire.write(data, power)

Parameters

data - A byte (or array of bytes) to write

power - Whether to leave power on after write (default is false)

Description

Write one or more bytes

Pin Class

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This is the built-in class for Pins, such as D0,D1,LED1, or BTN

You can call the methods on Pin, or you can use Wiring-style functions such as digitalWrite

Methods and Fields

function Pin.getInfo

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Call type:

function Pin.getInfo()

Returns

An object containing information about this pins

Description

Get information about this pin and its capabilities. Of the form:

{
  "port"      : "A", // the Pin's port on the chip
  "num"       : 12, // the Pin's number
  "in_addr"   : 0x..., // (if available) the address of the pin's input address in bit-banded memory (can be used with peek)
  "out_addr"  : 0x..., // (if available) the address of the pin's output address in bit-banded memory (can be used with poke)
  "analog"    : { ADCs : [1], channel : 12 }, // If analog input is available
  "functions" : {
    "TIM1":{type:"CH1, af:0},
    "I2C3":{type:"SCL", af:1}
  }
}
Will return undefined if pin is not valid.

Note: This is not available in devices with low flash memory

function Pin.getMode

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Call type:

function Pin.getMode()

Returns

The pin mode, as a string

Description

Return the current mode of the given pin. See pinMode for more information.

function Pin.mode

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Call type:

function Pin.mode(mode)

Parameters

mode - The mode - a string that is either 'analog', 'input', 'input_pullup', 'input_pulldown', 'output', 'opendrain', 'af_output' or 'af_opendrain'. Do not include this argument if you want to revert to automatic pin mode setting.

Description

Set the mode of the given pin. See pinMode for more information on pin modes.

constructor Pin

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Call type:

new Pin(value)

Parameters

value - A value to be converted to a pin. Can be a number, pin, or String.

Returns

A Pin object

Description

Creates a pin from the given argument (or returns undefined if no argument)

function Pin.read

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Call type:

function Pin.read()

Returns

Whether pin is a logical 1 or 0

Description

Returns the input state of the pin as a boolean.

Note: if you didn't call pinMode beforehand then this function will also reset the pin's state to "input"

Examples

This function is used in the following places in Espruino's documentation

function Pin.reset

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Call type:

function Pin.reset()

Description

Sets the output state of the pin to a 0

Note: if you didn't call pinMode beforehand then this function will also reset the pin's state to "output"

function Pin.set

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Call type:

function Pin.set()

Description

Sets the output state of the pin to a 1

Note: if you didn't call pinMode beforehand then this function will also reset the pin's state to "output"

function Pin.toggle

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Call type:

function Pin.toggle()

Returns

True if the pin is high after calling the function

Description

Toggles the state of the pin from off to on, or from on to off.

Note: This method doesn't currently work on the ESP8266 port of Espruino.

Note: if you didn't call pinMode beforehand then this function will also reset the pin's state to "output"

function Pin.write

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Call type:

function Pin.write(value)

Parameters

value - Whether to set output high (true/1) or low (false/0)

Description

Sets the output state of the pin to the parameter given

Note: if you didn't call pinMode beforehand then this function will also reset the pin's state to "output"

function Pin.writeAtTime

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Call type:

function Pin.writeAtTime(value, time)

Parameters

value - Whether to set output high (true/1) or low (false/0)

time - Time at which to write

Description

Sets the output state of the pin to the parameter given at the specified time.

Note: this doesn't change the mode of the pin to an output. To do that, you need to use pin.write(0) or pinMode(pin, 'output') first.

Note: This is not available in devices with low flash memory

process Class

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This class contains information about Espruino itself

Methods and Fields

process.env

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Call type:

process.env

Returns

An object

Description

Returns an Object containing various pre-defined variables. standard ones are BOARD, VERSION, FLASH, RAM, MODULES.

For example, to get a list of built-in modules, you can use process.env.MODULES.split(',')

process.memory

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Call type:

process.memory()

Returns

Information about memory usage

Description

Run a Garbage Collection pass, and return an object containing information on memory usage.

Memory units are specified in 'blocks', which are around 16 bytes each (depending on your device). The actual size is available in blocksize. See http://www.espruino.com/Performance for more information.

Note: To find free areas of flash memory, see require('Flash').getFree()

Examples

This function is used in the following places in Espruino's documentation

event process.uncaughtException

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Call type:

process.on('uncaughtException', function(exception) { ... });

Parameters

exception - The uncaught exception

Description

This event is called when an exception gets thrown and isn't caught (eg. it gets all the way back to the event loop).

You can use this for logging potential problems that might occur during execution when you might not be able to see what is written to the console, for example:

``` var lastError; process.on('uncaughtException', function(e) { lastError=e; print(e,e.stack?"\n"+e.stack:"") });

function checkError() { if (!lastError) return print("No Error"); print(lastError,lastError.stack?"\n"+lastError.stack:"") } ```

Note: When this is used, exceptions will cease to be reported on the console - which may make debugging difficult!

process.version

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Call type:

process.version

Returns

The version of Espruino

Description

Returns the version of Espruino as a String

Promise Class

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This is the built-in class for ES6 Promises

Methods and Fields

Promise.all

View MDN documentation

(top)

Call type:

Promise.all(promises)

Parameters

promises - An array of promises

Returns

A new Promise

Description

Return a new promise that is resolved when all promises in the supplied array are resolved.

Note: This is not available in devices with low flash memory

function Promise.catch

View MDN documentation

(top)

Call type:

function Promise.catch(onRejected)

Parameters

onRejected - A callback that is called when this promise is rejected

Returns

The original Promise

constructor Promise

View MDN documentation

(top)

Call type:

new Promise(executor)

Parameters

executor - A function of the form function (resolve, reject)

Returns

A Promise

Description

Create a new Promise. The executor function is executed immediately (before the constructor even returns) and

Note: This is not available in devices with low flash memory

Promise.reject

View MDN documentation

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Call type:

Promise.reject(promises)

Parameters

promises - Data to pass to the .catch handler

Returns

A new Promise

Description

Return a new promise that is already rejected (at idle it'll call .catch)

Note: This is not available in devices with low flash memory

Promise.resolve

View MDN documentation

(top)

Call type:

Promise.resolve(promises)

Parameters

promises - Data to pass to the .then handler

Returns

A new Promise

Description

Return a new promise that is already resolved (at idle it'll call .then)

Note: This is not available in devices with low flash memory

function Promise.then

View MDN documentation

(top)

Call type:

function Promise.then(onFulfilled, onRejected)

Parameters

onFulfilled - A callback that is called when this promise is resolved

onRejected - A callback that is called when this promise is rejected (or nothing)

Returns

The original Promise

ReferenceError Class

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The base class for reference errors - where a variable which doesn't exist has been accessed.

Methods and Fields

constructor ReferenceError

View MDN documentation

(top)

Call type:

new ReferenceError(message)

Parameters

message - An optional message string

Returns

A ReferenceError object

Description

Creates a ReferenceError object

function ReferenceError.toString

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Call type:

function ReferenceError.toString()

Returns

A String

RegExp Class

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The built-in class for handling Regular Expressions

Note: Espruino's regular expression parser does not contain all the features present in a full ES6 JS engine. However it does contain support for the all the basics.

Methods and Fields

function RegExp.exec

View MDN documentation

(top)

Call type:

function RegExp.exec(str)

Parameters

str - A string to match on

Returns

A result array, or null

Description

Test this regex on a string - returns a result array on success, or null otherwise.

/Wo/.exec("Hello World") will return:

[
 "Wo",
 "index": 6,
 "input": "Hello World"
]

Or with groups /W(o)rld/.exec("Hello World") returns:

[
 "World",
 "o", "index": 6,
 "input": "Hello World"
]

Note: This is not available in devices with low flash memory

constructor RegExp

View MDN documentation

(top)

Call type:

new RegExp(regex, regex)

Parameters

regex - A regular expression as a string

regex - Flags for the regular expression as a string

Returns

A RegExp object

Description

Creates a RegExp object, for handling Regular Expressions

Note: This is not available in devices with low flash memory

function RegExp.test

View MDN documentation

(top)

Call type:

function RegExp.test(str)

Parameters

str - A string to match on

Returns

true for a match, or false

Description

Test this regex on a string - returns true on a successful match, or false otherwise

Note: This is not available in devices with low flash memory

Serial Class

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This class allows use of the built-in USARTs

Methods may be called on the USB, Serial1, Serial2, Serial3, Serial4, Serial5 and Serial6 objects. While different processors provide different numbers of USARTs, you can always rely on at least Serial1 and Serial2

Instances

When data is sent to the Terminal object, Graphics.getInstance() is called and if an instance of Graphics is found then characters are written to it.

Methods and Fields

function Serial.available

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Call type:

function Serial.available()

Returns

How many bytes are available

Description

Return how many bytes are available to read. If there is already a listener for data, this will always return 0.

event Serial.data

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Call type:

Serial.on('data', function(data) { ... });

Parameters

data - A string containing one or more characters of received data

Description

The data event is called when data is received. If a handler is defined with X.on('data', function(data) { ... }) then it will be called, otherwise data will be stored in an internal buffer, where it can be retrieved with X.read()

Serial.find

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Call type:

Serial.find(pin)

Parameters

pin - A pin to search with

Returns

An object of type Serial, or undefined if one couldn't be found.

Description

Try and find a USART (Serial) hardware device that will work on this pin (eg. Serial1)

May return undefined if no device can be found.

event Serial.framing

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Call type:

Serial.on('framing', function() { ... });

Description

The framing event is called when there was activity on the input to the UART but the STOP bit wasn't in the correct place. This is either because there was noise on the line, or the line has been pulled to 0 for a long period of time.

To enable this, you must initialise Serial with SerialX.setup(..., { ..., errors:true });

Note: Even though there was an error, the byte will still be received and passed to the data handler.

Note: This only works on STM32 and NRF52 based devices (eg. all official Espruino boards)

function Serial.inject

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Call type:

function Serial.inject(data, ...)

Parameters

data, ... - One or more items to write. May be ints, strings, arrays, or special objects (see E.toUint8Array for more info).

Description

Add data to this device as if it came directly from the input - it will be returned via serial.on('data', ...);

Serial1.on('data', function(d) { print("Got",d); });
Serial1.inject('Hello World');
// prints "Got Hel","Got lo World" (characters can be split over multiple callbacks)

This is most useful if you wish to send characters to Espruino's REPL (console) while it is on another device.

Note: This is not available in devices with low flash memory

event Serial.parity

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Call type:

Serial.on('parity', function() { ... });

Description

The parity event is called when the UART was configured with a parity bit, and this doesn't match the bits that have actually been received.

To enable this, you must initialise Serial with SerialX.setup(..., { ..., errors:true });

Note: Even though there was an error, the byte will still be received and passed to the data handler.

Note: This only works on STM32 and NRF52 based devices (eg. all official Espruino boards)

function Serial.pipe

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Call type:

function Serial.pipe(destination, options)

Parameters

destination - The destination file/stream that will receive content from the source.

options - An optional object { chunkSize : int=32, end : bool=true, complete : function }
chunkSize : The amount of data to pipe from source to destination at a time
complete : a function to call when the pipe activity is complete
end : call the 'end' function on the destination when the source is finished

Description

Pipe this USART to a stream (an object with a 'write' method)

Note: This is not available in devices with low flash memory

Examples

This function is used in the following places in Espruino's documentation

function Serial.print

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Call type:

function Serial.print(string)

Parameters

string - A String to print

Description

Print a string to the serial port - without a line feed

Note: This function replaces any occurances of \n in the string with \r\n. To avoid this, use Serial.write.

Examples

This function is used in the following places in Espruino's documentation

function Serial.println

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Call type:

function Serial.println(string)

Parameters

string - A String to print

Description

Print a line to the serial port with a newline (\r\n) at the end of it.

Note: This function converts data to a string first, eg Serial.print([1,2,3]) is equivalent to Serial.print("1,2,3"). If you'd like to write raw bytes, useSerial.write`.

Examples

This function is used in the following places in Espruino's documentation

function Serial.read

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Call type:

function Serial.read(chars)

Parameters

chars - The number of characters to read, or undefined/0 for all available

Returns

A string containing the required bytes.

Description

Return a string containing characters that have been received

constructor Serial

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Call type:

new Serial()

Description

Create a software Serial port. This has limited functionality (only low baud rates), but it can work on any pins.

Use Serial.setup to configure this port.

function Serial.setConsole

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Call type:

function Serial.setConsole(force)

Parameters

force - Whether to force the console to this port

Description

Set this Serial port as the port for the JavaScript console (REPL).

Unless force is set to true, changes in the connection state of the board (for instance plugging in USB) will cause the console to change.

See E.setConsole for a more flexible version of this function.

Examples

This function is used in the following places in Espruino's documentation

function Serial.setup

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Call type:

function Serial.setup(baudrate, options)

Parameters

baudrate - The baud rate - the default is 9600

options - An optional structure containing extra information on initialising the serial port - see below.

Description

Setup this Serial port with the given baud rate and options.

eg.

Serial1.setup(9600,{rx:a_pin, tx:a_pin});

The second argument can contain:

{
  rx:pin,                           // Receive pin (data in to Espruino)
  tx:pin,                           // Transmit pin (data out of Espruino)
  ck:pin,                           // (default none) Clock Pin
  cts:pin,                          // (default none) Clear to Send Pin
  bytesize:8,                       // (default 8)How many data bits - 7 or 8
  parity:null/'none'/'o'/'odd'/'e'/'even', 
                                    // (default none) Parity bit
  stopbits:1,                       // (default 1) Number of stop bits to use
  flow:null/undefined/'none'/'xon', // (default none) software flow control
  path:null/undefined/string        // Linux Only - the path to the Serial device to use
  errors:false                      // (default false) whether to forward framing/parity errors
}

You can find out which pins to use by looking at your board's reference page and searching for pins with the UART/USART markers.

If not specified in options, the default pins are used for rx and tx (usually the lowest numbered pins on the lowest port that supports this peripheral). ck and cts are not used unless specified.

Note that even after changing the RX and TX pins, if you have called setup before then the previous RX and TX pins will still be connected to the Serial port as well - until you set them to something else using digitalWrite or pinMode.

Flow control can be xOn/xOff (flow:'xon') or hardware flow control (receive only) if cts is specified. If cts is set to a pin, the pin's value will be 0 when Espruino is ready for data and 1 when it isn't.

By default, framing or parity errors don't create framing or parity events on the Serial object because storing these errors uses up additional storage in the queue. If you're intending to receive a lot of malformed data then the queue might overflow E.getErrorFlags() would return FIFO_FULL. However if you need to respond to framing or parity errors then you'll need to use errors:true when initialising serial.

On Linux builds there is no default Serial device, so you must specify a path to a device - for instance: Serial1.setup(9600,{path:"/dev/ttyACM0"})

You can also set up 'software serial' using code like:

var s = new Serial();
s.setup(9600,{rx:a_pin, tx:a_pin});

However software serial doesn't use ck, cts, parity, flow or errors parts of the initialisation object.

function Serial.unsetup

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Call type:

function Serial.unsetup()

Description

If the serial (or software serial) device was set up, uninitialise it.

Note: This is not available in devices with low flash memory

function Serial.write

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Call type:

function Serial.write(data, ...)

Parameters

data, ... - One or more items to write. May be ints, strings, arrays, or special objects (see E.toUint8Array for more info).

Description

Write a character or array of data to the serial port

This method writes unmodified data, eg Serial.write([1,2,3]) is equivalent to Serial.write("\1\2\3"). If you'd like data converted to a string first, use Serial.print.

Examples

This function is used in the following places in Espruino's documentation

SPI Class

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This class allows use of the built-in SPI ports. Currently it is SPI master only.

Instances

Methods and Fields

SPI.find

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Call type:

SPI.find(pin)

Parameters

pin - A pin to search with

Returns

An object of type SPI, or undefined if one couldn't be found.

Description

Try and find an SPI hardware device that will work on this pin (eg. SPI1)

May return undefined if no device can be found.

function SPI.send

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Call type:

function SPI.send(data, nss_pin)

Parameters

data - The data to send - either an Integer, Array, String, or Object of the form {data: ..., count:#}

nss_pin - An nSS pin - this will be lowered before SPI output and raised afterwards (optional). There will be a small delay between when this is lowered and when sending starts, and also between sending finishing and it being raised.

Returns

The data that was returned

Description

Send data down SPI, and return the result. Sending an integer will return an integer, a String will return a String, and anything else will return a Uint8Array.

Sending multiple bytes in one call to send is preferable as they can then be transmitted end to end. Using multiple calls to send() will result in significantly slower transmission speeds.

For maximum speeds, please pass either Strings or Typed Arrays as arguments. Note that you can even pass arrays of arrays, like [1,[2,3,4],5]

Examples

This function is used in the following places in Espruino's documentation

function SPI.send4bit

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Call type:

function SPI.send4bit(data, bit0, bit1, nss_pin)

Parameters

data - The data to send - either an integer, array, or string

bit0 - The 4 bits to send for a 0 (MSB first)

bit1 - The 4 bits to send for a 1 (MSB first)

nss_pin - An nSS pin - this will be lowered before SPI output and raised afterwards (optional). There will be a small delay between when this is lowered and when sending starts, and also between sending finishing and it being raised.

Description

Send data down SPI, using 4 bits for each 'real' bit (MSB first). This can be useful for faking one-wire style protocols

Sending multiple bytes in one call to send is preferable as they can then be transmitted end to end. Using multiple calls to send() will result in significantly slower transmission speeds.

function SPI.send8bit

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Call type:

function SPI.send8bit(data, bit0, bit1, nss_pin)

Parameters

data - The data to send - either an integer, array, or string

bit0 - The 8 bits to send for a 0 (MSB first)

bit1 - The 8 bits to send for a 1 (MSB first)

nss_pin - An nSS pin - this will be lowered before SPI output and raised afterwards (optional). There will be a small delay between when this is lowered and when sending starts, and also between sending finishing and it being raised

Description

Send data down SPI, using 8 bits for each 'real' bit (MSB first). This can be useful for faking one-wire style protocols

Sending multiple bytes in one call to send is preferable as they can then be transmitted end to end. Using multiple calls to send() will result in significantly slower transmission speeds.

Note: This is not available in devices with low flash memory

function SPI.setup

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Call type:

function SPI.setup(options)

Parameters

options - An Object containing extra information on initialising the SPI port

Description

Set up this SPI port as an SPI Master.

Options can contain the following (defaults are shown where relevant):

{
  sck:pin, 
  miso:pin, 
  mosi:pin, 
  baud:integer=100000, // ignored on software SPI
  mode:integer=0, // between 0 and 3
  order:string='msb' // can be 'msb' or 'lsb' 
  bits:8 // only available for software SPI
}

If sck,miso and mosi are left out, they will automatically be chosen. However if one or more is specified then the unspecified pins will not be set up.

You can find out which pins to use by looking at your board's reference page and searching for pins with the SPI marker. Some boards such as those based on nRF52 chips can have SPI on any pins, so don't have specific markings.

The SPI mode is between 0 and 3 - see http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus#Clock_polarity_and_phase

On STM32F1-based parts, you cannot mix AF and non-AF pins (SPI pins are usually grouped on the chip - and you can't mix pins from two groups). Espruino will not warn you about this.

constructor SPI

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Call type:

new SPI()

Description

Create a software SPI port. This has limited functionality (no baud rate), but it can work on any pins.

Use SPI.setup to configure this port.

function SPI.write

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Call type:

function SPI.write(data, ...)

Parameters

data, ... - One or more items to write. May be ints, strings, arrays, or special objects (see E.toUint8Array for more info).
If the last argument is a pin, it is taken to be the NSS pin

Description

Write a character or array of characters to SPI - without reading the result back.

For maximum speeds, please pass either Strings or Typed Arrays as arguments.

Storage Library

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This module allows you to read and write part of the nonvolatile flash memory of your device using a filesystem-like API.

Also see the Flash library, which provides a low level, more dangerous way to access all parts of your flash memory.

Methods and Fields

Storage.compact

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Call type:

require("Storage").compact()

Description

The Flash Storage system is journaling. To make the most of the limited write cycles of Flash memory, Espruino marks deleted/replaced files as garbage and moves on to a fresh part of flash memory. Espruino only fully erases those files when it is running low on flash, or when compact is called.

compact may fail if there isn't enough RAM free on the stack to use as swap space, however in this case it will not lose data.

Note: compact rearranges the contents of memory. If code is referencing that memory (eg. functions that have their code stored in flash) then they may become garbled when compaction happens. To avoid this, call eraseFiles before uploading data that you intend to reference to ensure that uploaded files are right at the start of flash and cannot be compacted further.

Note: This is not available in devices with low flash memory

Storage.erase

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Call type:

require("Storage").erase(name)

Parameters

name - The filename - max 8 characters (case sensitive)

Description

Erase a single file from the flash storage area.

Note: This is not available in devices with low flash memory

Storage.eraseAll

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Call type:

require("Storage").eraseAll()

Description

Erase the flash storage area. This will remove all files created with require("Storage").write(...) as well as any code saved with save() or E.setBootCode().

Note: This is not available in devices with low flash memory

Storage.getFree

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Call type:

require("Storage").getFree()

Returns

The amount of free bytes

Description

Return the amount of free bytes available in Storage. Due to fragmentation there may be more bytes available, but this represents the maximum size of file that can be written.

Note: This is not available in devices with low flash memory

Storage.list

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Call type:

require("Storage").list(regex)

Parameters

regex - (optional) If supplied, filenames are checked against this regular expression (with String.match(regexp)) to see if they match before being returned

Returns

An array of filenames

Description

List all files in the flash storage area. An array of Strings is returned.

Note: This will output system files (eg. saved code) as well as files that you may have written.

Note: This is not available in devices with low flash memory

Storage.open

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Call type:

require("Storage").open(name, mode)

Parameters

name - The filename - max 7 characters (case sensitive)

mode - The open mode - must be either 'r' for read,'w' for write , or 'a' for append

Returns

An object containing {read,write,erase}

Description

Open a file in the Storage area. This can be used for appending data (normal read/write operations only write the entire file).

Please see StorageFile for more information (and examples).

Note: These files write through immediately - they do not need closing.

Note: This is not available in devices with low flash memory

Storage.read

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Call type:

require("Storage").read(name, offset, length)

Parameters

name - The filename - max 8 characters (case sensitive)

offset - (optional) The offset in bytes to start from

length - (optional) The length to read in bytes (if <=0, the entire file is read)

Returns

A string of data

Description

Read a file from the flash storage area that has been written with require("Storage").write(...).

This function returns a String that points to the actual memory area in read-only memory, so it won't use up RAM.

If you evaluate this string with eval, any functions contained in the String will keep their code stored in flash memory.

Note: This is not available in devices with low flash memory

Storage.readArrayBuffer

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Call type:

require("Storage").readArrayBuffer(name)

Parameters

name - The filename - max 8 characters (case sensitive)

Returns

An ArrayBuffer containing data from the file, or undefined

Description

Read a file from the flash storage area that has been written with require("Storage").write(...), and return the raw binary data as an ArrayBuffer.

This can be used:

Note: This is not available in devices with low flash memory

Storage.readJSON

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Call type:

require("Storage").readJSON(name, noExceptions)

Parameters

name - The filename - max 8 characters (case sensitive)

noExceptions - If true and the JSON is not valid, just return undefined - otherwise an Exception is thrown

Returns

An object containing parsed JSON from the file, or undefined

Description

Read a file from the flash storage area that has been written with require("Storage").write(...), and parse JSON in it into a JavaScript object.

This is identical to JSON.parse(require("Storage").read(...)). It will throw an exception if the data in the file is not valid JSON.

Note: This is not available in devices with low flash memory

Storage.write

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Call type:

require("Storage").write(name, data, offset, size)

Parameters

name - The filename - max 8 characters (case sensitive)

data - The data to write

offset - The offset within the file to write

size - The size of the file (if a file is to be created that is bigger than the data)

Returns

True on success, false on failure

Description

Write/create a file in the flash storage area. This is nonvolatile and will not disappear when the device resets or power is lost.

Simply write require("Storage").write("MyFile", "Some data") to write a new file, and require("Storage").read("MyFile") to read it.

If you supply:

Note: If an array is supplied it will not be converted to JSON. To be explicit about the conversion you can use Storage.writeJSON

You may also create a file and then populate data later as long as you don't try and overwrite data that already exists. For instance:

var f = require("Storage");
f.write("a","Hello",0,14);
f.write("a"," ",5);
f.write("a","World!!!",6);
print(f.read("a"));

This can be useful if you've got more data to write than you have RAM available.

Note: This is not available in devices with low flash memory

Storage.writeJSON

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Call type:

require("Storage").writeJSON(name, data)

Parameters

name - The filename - max 8 characters (case sensitive)

data - The JSON data to write

Returns

True on success, false on failure

Description

Write/create a file in the flash storage area. This is nonvolatile and will not disappear when the device resets or power is lost.

Simply write require("Storage").writeJSON("MyFile", [1,2,3]) to write a new file, and require("Storage").readJSON("MyFile") to read it.

This is equivalent to: require("Storage").write(name, JSON.stringify(data))

Note: This is not available in devices with low flash memory

StorageFile Class

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These objects are created from require("Storage").open and allow Storage items to be read/written.

The Storage library writes into Flash memory (which can only be erased in chunks), and unlike a normal filesystem it allocates files in one long contiguous area to allow them to be accessed easily from Espruino.

This presents a challenge for StorageFile which allows you to append to a file, so instead StorageFile stores files in chunks. It uses 7 character filenames and uses the last character to denote the chunk number (eg "foobar\1", "foobar\2", etc).

This means that while StorageFile files exist in the same area as those from Storage, they should be read using StorageFile.open (and not Storage.read).

f = s.open("foobar","w");
f.write("Hell");
f.write("o World\n");
f.write("Hello\n");
f.write("World 2\n");
// there's no need to call 'close'
// then
f = s.open("foobar","r");
f.read(13) // "Hello World\nH"
f.read(13) // "ello\nWorld 2\n"
f.read(13) // "Hello World 3"
f.read(13) // "\n"
f.read(13) // undefined
// or
f = s.open("foobar","r");
f.readLine() // "Hello World\n"
f.readLine() // "Hello\n"
f.readLine() // "World 2\n"
f.readLine() // "Hello World 3\n"
f.readLine() // undefined
// now get rid of file
f.erase();

Note: StorageFile uses the fact that all bits of erased flash memory are 1 to detect the end of a file. As such you should not write character code 255 ("\xFF") to these files.

Methods and Fields

function StorageFile.erase

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Call type:

function StorageFile.erase()

Description

Erase this file

Note: This is not available in devices with low flash memory

function StorageFile.getLength

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Call type:

function StorageFile.getLength()

Returns

The current length in bytes of the file

Description

Return the length of the current file.

This requires Espruino to read the file from scratch, which is not a fast operation.

Note: This is not available in devices with low flash memory

function StorageFile.read

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Call type:

function StorageFile.read(len)

Parameters

len - How many bytes to read

Returns

A String, or undefined

Description

Read 'len' bytes of data from the file, and return a String containing those bytes.

If the end of the file is reached, the String may be smaller than the amount of bytes requested, or if the file is already at the end, undefined is returned.

Note: This is not available in devices with low flash memory

function StorageFile.readLine

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Call type:

function StorageFile.readLine()

Returns

A line of data

Description

Read a line of data from the file (up to and including "\n")

Note: This is not available in devices with low flash memory

function StorageFile.write

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Call type:

function StorageFile.write(data)

Parameters

data - The data to write. This should not include '\xFF' (character code 255)

Description

Append the given data to a file. You should not attempt to append "\xFF" (character code 255).

Note: This is not available in devices with low flash memory

String Class

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This is the built-in class for Text Strings.

Text Strings in Espruino are not zero-terminated, so you can store zeros in them.

Methods and Fields

function String.charAt

View MDN documentation

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Call type:

function String.charAt(pos)

Parameters

pos - The character number in the string. Negative values return characters from end of string (-1 = last char)

Returns

The character in the string

Description

Return a single character at the given position in the String.

function String.charCodeAt

View MDN documentation

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Call type:

function String.charCodeAt(pos)

Parameters

pos - The character number in the string. Negative values return characters from end of string (-1 = last char)

Returns

The integer value of a character in the string

Description

Return the integer value of a single character at the given position in the String.

Note that this returns 0 not 'NaN' for out of bounds characters

function String.endsWith

View MDN documentation

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Call type:

function String.endsWith(searchString, length)

Parameters

searchString - The string to search for

length - The 'end' of the string - if left off the actual length of the string is used

Returns

true if the given characters are found at the end of the string, otherwise, false.

String.fromCharCode

View MDN documentation

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Call type:

String.fromCharCode(code, ...)

Parameters

code, ... - One or more character codes to create a string from (range 0-255).

Returns

The character

Description

Return the character(s) represented by the given character code(s).

Examples

This function is used in the following places in Espruino's documentation

function String.includes

View MDN documentation

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Call type:

function String.includes(substring, fromIndex)

Parameters

substring - The string to search for

fromIndex - The start character index (or 0 if not defined)

Returns

true if the given characters are in the string, otherwise, false.

function String.indexOf

View MDN documentation

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Call type:

function String.indexOf(substring, fromIndex)

Parameters

substring - The string to search for

fromIndex - Index to search from

Returns

The index of the string, or -1 if not found

Description

Return the index of substring in this string, or -1 if not found

Examples

This function is used in the following places in Espruino's documentation

function String.lastIndexOf

View MDN documentation

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Call type:

function String.lastIndexOf(substring, fromIndex)

Parameters

substring - The string to search for

fromIndex - Index to search from

Returns

The index of the string, or -1 if not found

Description

Return the last index of substring in this string, or -1 if not found

property String.length

View MDN documentation

(top)

Call type:

property String.length

Returns

The value of the string

Description

Find the length of the string

function String.match

View MDN documentation

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Call type:

function String.match(substr)

Parameters

substr - Substring or RegExp to match

Returns

A match array or null (see below):

Description

Matches an occurrence subStr in the string.

Returns null if no match, or:

``` "abcdef".match("b") == [ "b", // array index 0 - the matched string index: 1, // the start index of the match input: "b" // the input string ]

"abcdefabcdef".match(/bcd/) == [ "bcd", index: 1, input: "abcdefabcdef" ] ```

'Global' RegEx matches just return an array of matches (with no indices):

"abcdefabcdef".match(/bcd/g) = [
  "bcd",
  "bcd"
 ]

function String.repeat

View MDN documentation

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Call type:

function String.repeat(count)

Parameters

count - An integer with the amount of times to repeat this String

Returns

A string containing repetitions of this string

Description

Repeat this string the given number of times.

Note: This is not available in devices with low flash memory

function String.replace

View MDN documentation

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Call type:

function String.replace(subStr, newSubStr)

Parameters

subStr - The string to search for

newSubStr - The string to replace it with

Returns

This string with subStr replaced

Description

Search and replace ONE occurrance of subStr with newSubStr and return the result. This doesn't alter the original string. Regular expressions not supported.

function String.slice

View MDN documentation

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Call type:

function String.slice(start, end)

Parameters

start - The start character index, if negative it is from the end of the string

end - The end character index, if negative it is from the end of the string, and if omitted it is the end of the string

Returns

Part of this string from start for len characters

function String.split

View MDN documentation

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Call type:

function String.split(separator)

Parameters

separator - The separator String or RegExp to use

Returns

Part of this string from start for len characters

Description

Return an array made by splitting this string up by the separator. eg. '1,2,3'.split(',')==['1', '2', '3']

Regular Expressions can also be used to split strings, eg. '1a2b3 4'.split(/[^0-9]/)==['1', '2', '3', '4'].

function String.startsWith

View MDN documentation

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Call type:

function String.startsWith(searchString, position)

Parameters

searchString - The string to search for

position - The start character index (or 0 if not defined)

Returns

true if the given characters are found at the beginning of the string, otherwise, false.

constructor String

View MDN documentation

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Call type:

new String(str, ...)

Parameters

str, ... - A value to turn into a string. If undefined or not supplied, an empty String is created.

Returns

A String

Description

Create a new String

function String.substr

View MDN documentation

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Call type:

function String.substr(start, len)

Parameters

start - The start character index

len - The number of characters

Returns

Part of this string from start for len characters

function String.substring

View MDN documentation

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Call type:

function String.substring(start, end)

Parameters

start - The start character index

end - The end character index

Returns

The part of this string between start and end

function String.toLowerCase

View MDN documentation

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Call type:

function String.toLowerCase()

Parameters

Returns

The lowercase version of this string

function String.toUpperCase

View MDN documentation

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Call type:

function String.toUpperCase()

Parameters

Returns

The uppercase version of this string

function String.trim

View MDN documentation

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Call type:

function String.trim()

Returns

A String with Whitespace removed from the beginning and end

Description

Return a new string with any whitespace (tabs, space, form feed, newline, carriage return, etc) removed from the beginning and end.

SyntaxError Class

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The base class for syntax errors

Methods and Fields

constructor SyntaxError

View MDN documentation

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Call type:

new SyntaxError(message)

Parameters

message - An optional message string

Returns

A SyntaxError object

Description

Creates a SyntaxError object

function SyntaxError.toString

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Call type:

function SyntaxError.toString()

Returns

A String

tensorflow Library

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Methods and Fields

tensorflow.create

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Call type:

require("tensorflow").create(arenaSize, model)

Parameters

arenaSize - The TensorFlow Arena size

model - The model to use - this should be a flat array/string

Returns

A tensorflow instance

TFMicroInterpreter Class

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Class containing an instance of TFMicroInterpreter

Methods and Fields

function TFMicroInterpreter.getInput

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Call type:

function TFMicroInterpreter.getInput()

Returns

An arraybuffer referencing the input data

function TFMicroInterpreter.getOutput

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Call type:

function TFMicroInterpreter.getOutput()

Returns

An arraybuffer referencing the output data

function TFMicroInterpreter.invoke

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Call type:

function TFMicroInterpreter.invoke()

TypeError Class

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The base class for type errors

Methods and Fields

function TypeError.toString

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Call type:

function TypeError.toString()

Returns

A String

constructor TypeError

View MDN documentation

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Call type:

new TypeError(message)

Parameters

message - An optional message string

Returns

A TypeError object

Description

Creates a TypeError object

Uint16Array Class

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This is the built-in JavaScript class for a typed array of 16 bit unsigned integers.

Instantiate this in order to efficiently store arrays of data (Espruino's normal arrays store data in a map, which is inefficient for non-sparse arrays).

Arrays of this type include all the methods from ArrayBufferView

Methods and Fields

constructor Uint16Array

View MDN documentation

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Call type:

new Uint16Array(arr, byteOffset, length)

Parameters

arr - The array or typed array to base this off, or an integer which is the array length

byteOffset - The byte offset in the ArrayBuffer (ONLY IF the first argument was an ArrayBuffer)

length - The length (ONLY IF the first argument was an ArrayBuffer)

Returns

A typed array

Description

Create a typed array based on the given input. Either an existing Array Buffer, an Integer as a Length, or a simple array. If an ArrayBufferView (eg. Uint8Array rather than ArrayBuffer) is given, it will be completely copied rather than referenced.

Uint24Array Class

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This is the built-in JavaScript class for a typed array of 24 bit unsigned integers.

Instantiate this in order to efficiently store arrays of data (Espruino's normal arrays store data in a map, which is inefficient for non-sparse arrays).

Arrays of this type include all the methods from ArrayBufferView

Methods and Fields

constructor Uint24Array

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Call type:

new Uint24Array(arr, byteOffset, length)

Parameters

arr - The array or typed array to base this off, or an integer which is the array length

byteOffset - The byte offset in the ArrayBuffer (ONLY IF the first argument was an ArrayBuffer)

length - The length (ONLY IF the first argument was an ArrayBuffer)

Returns

A typed array

Description

Create a typed array based on the given input. Either an existing Array Buffer, an Integer as a Length, or a simple array. If an ArrayBufferView (eg. Uint8Array rather than ArrayBuffer) is given, it will be completely copied rather than referenced.

Uint32Array Class

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This is the built-in JavaScript class for a typed array of 32 bit unsigned integers.

Instantiate this in order to efficiently store arrays of data (Espruino's normal arrays store data in a map, which is inefficient for non-sparse arrays).

Arrays of this type include all the methods from ArrayBufferView

Methods and Fields

constructor Uint32Array

View MDN documentation

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Call type:

new Uint32Array(arr, byteOffset, length)

Parameters

arr - The array or typed array to base this off, or an integer which is the array length

byteOffset - The byte offset in the ArrayBuffer (ONLY IF the first argument was an ArrayBuffer)

length - The length (ONLY IF the first argument was an ArrayBuffer)

Returns

A typed array

Description

Create a typed array based on the given input. Either an existing Array Buffer, an Integer as a Length, or a simple array. If an ArrayBufferView (eg. Uint8Array rather than ArrayBuffer) is given, it will be completely copied rather than referenced.

Note: This is not available in devices with low flash memory

Uint8Array Class

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This is the built-in JavaScript class for a typed array of 8 bit unsigned integers.

Instantiate this in order to efficiently store arrays of data (Espruino's normal arrays store data in a map, which is inefficient for non-sparse arrays).

Arrays of this type include all the methods from ArrayBufferView

Methods and Fields

constructor Uint8Array

View MDN documentation

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Call type:

new Uint8Array(arr, byteOffset, length)

Parameters

arr - The array or typed array to base this off, or an integer which is the array length

byteOffset - The byte offset in the ArrayBuffer (ONLY IF the first argument was an ArrayBuffer)

length - The length (ONLY IF the first argument was an ArrayBuffer)

Returns

A typed array

Description

Create a typed array based on the given input. Either an existing Array Buffer, an Integer as a Length, or a simple array. If an ArrayBufferView (eg. Uint8Array rather than ArrayBuffer) is given, it will be completely copied rather than referenced.

Examples

This function is used in the following places in Espruino's documentation

Uint8ClampedArray Class

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This is the built-in JavaScript class for a typed array of 8 bit unsigned integers that are automatically clamped to the range 0 to 255.

Instantiate this in order to efficiently store arrays of data (Espruino's normal arrays store data in a map, which is inefficient for non-sparse arrays).

Arrays of this type include all the methods from ArrayBufferView

Methods and Fields

constructor Uint8ClampedArray

View MDN documentation

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Call type:

new Uint8ClampedArray(arr, byteOffset, length)

Parameters

arr - The array or typed array to base this off, or an integer which is the array length

byteOffset - The byte offset in the ArrayBuffer (ONLY IF the first argument was an ArrayBuffer)

length - The length (ONLY IF the first argument was an ArrayBuffer)

Returns

A typed array

Description

Create a typed array based on the given input. Either an existing Array Buffer, an Integer as a Length, or a simple array. If an ArrayBufferView (eg. Uint8Array rather than ArrayBuffer) is given, it will be completely copied rather than referenced.

Clamped arrays clamp their values to the allowed range, rather than 'wrapping'. e.g. after a[0]=12345;, a[0]==255.

Waveform Class

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This class handles waveforms. In Espruino, a Waveform is a set of data that you want to input or output.

Methods and Fields

function Waveform.startInput

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Call type:

function Waveform.startInput(output, freq, options)

Parameters

output - The pin to output on

freq - The frequency to output each sample at

options - Optional options struct {time:float,repeat:bool} where: time is the that the waveform with start output at, e.g. getTime()+1 (otherwise it is immediate), repeat is a boolean specifying whether to repeat the give sample

Description

Will start inputting the waveform on the given pin that supports analog. If not repeating, it'll emit a finish event when it is done.

Note: This is not available in devices with low flash memory

function Waveform.startOutput

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Call type:

function Waveform.startOutput(output, freq, options)

Parameters

output - The pin to output on

freq - The frequency to output each sample at

options - Optional options struct {time:float,repeat:bool} where: time is the that the waveform with start output at, e.g. getTime()+1 (otherwise it is immediate), repeat is a boolean specifying whether to repeat the give sample

Description

Will start outputting the waveform on the given pin - the pin must have previously been initialised with analogWrite. If not repeating, it'll emit a finish event when it is done.

Note: This is not available in devices with low flash memory

function Waveform.stop

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Call type:

function Waveform.stop()

Description

Stop a waveform that is currently outputting

Note: This is not available in devices with low flash memory

constructor Waveform

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Call type:

new Waveform(samples, options)

Parameters

samples - The number of samples

options - Optional options struct {doubleBuffer:bool, bits : 8/16} where: doubleBuffer is whether to allocate two buffers or not (default false), and bits is the amount of bits to use (default 8).

Returns

An Waveform object

Description

Create a waveform class. This allows high speed input and output of waveforms. It has an internal variable called buffer (as well as buffer2 when double-buffered - see options below) which contains the data to input/output.

When double-buffered, a 'buffer' event will be emitted each time a buffer is finished with (the argument is that buffer). When the recording stops, a 'finish' event will be emitted (with the first argument as the buffer).

Note: This is not available in devices with low flash memory