129 lines
2.9 KiB
Markdown
129 lines
2.9 KiB
Markdown
MicroPython WebAssembly
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=======================
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MicroPython for [WebAssembly](https://webassembly.org/).
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Dependencies
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------------
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Building webassembly port bears the same requirements as the standard
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MicroPython ports with the addition of Emscripten (and uglify-js for the
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minified file).
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The output includes `micropython.js` (a JavaScript wrapper for the
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MicroPython runtime) and `firmware.wasm` (actual MicroPython compiled to
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WASM).
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Build instructions
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------------------
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In order to build micropython.js, run:
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$ make
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To generate the minified file micropython.min.js, run:
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$ make min
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Running with Node.js
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--------------------
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Access the repl with:
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$ node build/micropython.js
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Stack size may be modified using:
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$ node build/micropython.js -X stack=64K
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Where stack size may be represented in Bytes, KiB or MiB.
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MicroPython scripts may be executed using:
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$ node build/micropython.js hello.py
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Alternatively micropython.js may by accessed by other javascript programs in node
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using the require command and the general API outlined below. For example:
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```javascript
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var mp_js = require('./build/micropython.js');
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mp_js_init(64 * 1024);
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await mp_js_do_str("print('hello world')\n");
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```
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Running with HTML
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-----------------
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The prerequisite for browser operation of micropython.js is to listen to the
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`micropython-print` event, which is passed data when MicroPython code prints
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something to stdout. The following code demonstrates basic functionality:
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```html
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<!doctype html>
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<html>
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<head>
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<script src="build/micropython.js"></script>
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</head>
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<body>
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<pre id="micropython-stdout"></pre>
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<script>
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document.addEventListener("micropython-print", function(e) {
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let output = document.getElementById("micropython-stdout");
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output.innerText += new TextDecoder().decode(e.detail);
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}, false);
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var mp_js_startup = Module["onRuntimeInitialized"];
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Module["onRuntimeInitialized"] = async function() {
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mp_js_startup();
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mp_js_init(64 * 1024);
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await mp_js_do_str("print('hello world')");
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};
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</script>
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</body>
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</html>
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```
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MicroPython code execution will suspend the browser so be sure to atomize usage
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within this environment. Unfortunately interrupts have not been implemented for the
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browser.
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Testing
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-------
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Run the test suite using:
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$ make test
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API
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---
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The following functions have been exposed to javascript.
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```
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mp_js_init(stack_size)
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```
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Initialize MicroPython with the given stack size in bytes. This must be
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called before attempting to interact with MicroPython.
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```
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await mp_js_do_str(code)
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```
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Execute the input code. `code` must be a `string`.
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```
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mp_js_init_repl()
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```
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Initialize MicroPython repl. Must be called before entering characters into
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the repl.
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```
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await mp_js_process_char(char)
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```
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Input character into MicroPython repl. `char` must be of type `number`. This
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will execute MicroPython code when necessary.
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