espruino

Espruino Tools

This repository contains a set of tools for the Espruino JavaScript Interpreter.

While it is used directly by the Espruino Web IDE, there's are also simple command-line and node.js interfaces.

Command-line

When installed as a Node module with npm install -g espruino you get a command-line tool called espruino:

USAGE: espruino ...options... [file_to_upload.js]

  -h,--help               : Show this message
  -v,--verbose            : Verbose
  -q,--quiet              : Quiet - apart from Espruino output
  -m,--minify             : Minify the code before sending it
  -w,--watch              : If uploading a JS file, continue to watch it for",
                            changes and upload again if it does.",
  -p,--port /dev/ttyX     : Specify port(s) to connect to
  -b baudRate             : Set the baud rate of the serial connection
                            No effect when using USB, default: 9600
  --ble                   : Try and connect with Bluetooth Low Energy (using the 'bleat' module)",
  --list                  : List all available devices and exit
  -t,--time               : Set Espruino's time when uploading code
  -o out.js               : Write the actual JS code sent to Espruino to a file
  -f firmware.bin         : Update Espruino's firmware to the given file
                              Espruino must be in bootloader mode
                              Optionally skip N first bytes of the bin file,
  -e command              : Evaluate the given expression on Espruino
                              If no file to upload is specified but you use -e,
                              Espruino will not be reset

If no file, command, or firmware update is specified, this will act
as a terminal for communicating directly with Espruino. Press Ctrl-C
twice to exit.

For instance:

# Connect to Espruno and act as a terminal app  (IF Espruino is the only serial port reported)
espruino

# Connect to Espruino on the specified port, act as a terminal
espruino -p /dev/ttyACM0

# Write a program to Espruino (IF Espruino is the only serial port reported)
espruino myprogram.js

# Otherwise you'll want to specify the exact port first
espruino -p /dev/ttyACM0 myprogram.js

# Write a program to Espruino and drop into a terminal, but then monitor
# myprogram.js for changes and upload it again
espruino --watch myprogram.js

# Load a file into two Espruino boards
espruino -p /dev/ttyACM1 /dev/ttyACM2 mycode.js

# Load a file into Espruino and save
espruino -p /dev/ttyACM0 mycode.js -e "save()"

# Execute a single command on the default serial device
espruino -e "digitalWrite(LED1,1);"

NPM Module

This is the NPM module espruino.

Once installed with npm install -g espruino it contains the following functions:

var esp = require("espruino");

/** Initialise EspruinoTools and call the callback.
 When the callback is called, the global variable 'Espruino'
 will then contain everything that's needed to use EspruinoTools */
esp.init(callback);

/** Send a file to an Espruino on the given port, call the callback when done (calls 'init' automatically) */
esp.sendFile (port, filename, callback);

/** Execute an expression on Espruino, call the callback with the result (calls 'init' automatically) */
esp.expr(port, expr, callback(result));

/** Flash the given firmware file to an Espruino board (calls 'init' automatically) */
esp.flash(port, filename, callback);

For example, to get the current temperature of the board you can do:

require('espruino').expr('/dev/ttyACM0', 'E.getTemperature()', function(temp) {
        console.log('Current temperature is '+temp);
});

Note: this module is currently prints a lot of debug information to console.log when working.

If you want to set specific options, for example Baud rate, initialise everything explicitly with init, set the options, and then call the function you need:

var esp = require("espruino");
esp.init(function() {
  Espruino.Config.BAUD_RATE = "115200";
  esp.sendFile(port, filename, function() {
    console.log('Done!');
  })
});

Internals

This isn't well documented right now, but basically:

• You have a bunch of source files that are automatically loaded by index.js
• These add things to Espruino.Core or Espruino.Plugins
• They also register themselves as processors with Espruino.addProcessor. For instance you might register for "transformForEspruino" in which case you can do something to the JS code before it's finally sent to Espruino.
• You then call into Espruino.Core.X or Espruino.Plugins.Y to do what you want

It's not ideal for node.js, but was designed to run in the Web browser for the Espruino Web IDE

To Do

While EspruinoTools has been in use in the Web IDE for a while, the command-line tool still needs a lot of work.

Main things that need attention at the moment are:

• The local filesystem should be checked for modules that are referenced from Espruino's code, maybe modules folder to avoid confusion with node.
• Remove usage of console.log and replace it with something else that can be easily disabled when used as a module

Cool stuff would be:

• Add a command-line option (-w?) to watch a file and re-upload it when it has changed
• Allow the final code that's sent to Espruino to be written to a file (useful when there's Compilation/assembly/modules/minification involved).
• Add an option to expose the serial connection via WebSockets. Something like the online Web IDE could the communicate directly.
• Support for Nordic UART via bleat
• Support for using the Espruino JS->C compiler offline, if arm-node-eabi-gcc is installed.

Contributing

Contributions would he hugely appreciated - sadly I'm stretched a bit thin with Espruino, Espruino's modules, the Web IDE and forum, so this isn't getting the love it deserves.

Please be aware that the Espruino Web IDE (and even a truly online version of the Web IDE depend heavily this code - so try not to do anything that will break them).

Code Style

• Please stick to a K&R style with no tabs and 2 spaces per indent
• Filenames should start with a lowerCase letter, and different words should be capitalised, not split with underscores

Code Outline

• Core functionality goes in core, Plugins go in plugins. See plugins/_examplePlugin.js for an example layout
• Serial port handlers are a special case - they just add themselves to the Espruino.Core.Serial.devices array when loaded.
• Plugins/core need to implement in init function, which is called when the document (and settings) have loaded.
• Plugins can respond to specific events using Espruino.addProcessor. For instance you can use Espruino.addProcessor("transformForEspruino", function (data,callback) { .. }) and can modify code before it is sent to Espruino. Events types are documented at the top of espruino.js
• Config is stored in Espruino.Config.FOO and is changed with Espruino.Config.set("FOO", value). Espruino.Core.Config.add can be used to add an option to the Settings menu.

RELATED

There are other tools available to program Espruino:

• (Recommended) The Espruino Web IDE (Google Chrome)
• Online version of the Web IDE (any browser - limited to serial over audio or Web Bluetooth)
• espruino-cli (node.js)
• node-espruino (node.js)
• grunt-espruino (node.js)
• espruino (Go)

Note: while other tools exist, this EspruinoTools module and the Web IDE which uses it are maintained alongside the Espruino firmware, and tend to have support for various features and edge cases that other tools might not.