MicroPython port to ESP8266

This is a highly experimental port of MicroPython for the WiFi modules based on Espressif ESP8266 chip.

WARNING: The port is highly experimental and any APIs are subject to change.

Currently implemented features include:

REPL (Python prompt) over UART0.
24k heap RAM available for Python code.
Garbage collector, exceptions.
Unicode support.
Builtin modules: gc, array, collections, io, struct, sys, esp, network.
C long-long type used as bignum implementation (gives 64 bit signed ints).
Rudimentary WiFi support in station mode.
Sockets with callbacks.
Basic GPIO support.

Note that floating-point numbers are not supported.

On the TODO list:

Full wifi support.
Internal filesystem using the flash.
...

Build instructions

The tool chain required for the build is the OpenSource ESP SDK, which can be found at https://github.com/pfalcon/esp-open-sdk. Clone this repository and run make in its directory to build and install the SDK locally.

Then, to build MicroPython for the ESP8266, just run:

$ make

This should produce binary images in the build/ subdirectory. To flash them to your ESP8266, use:

$ make deploy

This will use the esptool.py script to download the images. You must have your ESP module in the bootloader, and connected to a serial port on your PC. The default serial port is /dev/ttyACM0. To specify another, use, eg:

$ make PORT=/dev/ttyUSB0 deploy

The images that are built are:

firmware.elf-0x00000.bin: to be flashed at 0x00000
firmware.elf-0x10000.bin: to be flashed at 0x10000

There is also a combined image, made up of the above 2 binary files with the appropriate padding:

firmware-combined.bin: to be flashed at 0x00000