circuitpython/ports/esp8266/README.md

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MicroPython port to ESP8266
===========================
This is an experimental port of MicroPython for the WiFi modules based
on Espressif ESP8266 chip.
WARNING: The port is experimental and many APIs are subject to change.
Supported features include:
- REPL (Python prompt) over UART0.
- Garbage collector, exceptions.
- Unicode support.
- Builtin modules: gc, array, collections, io, struct, sys, esp, network,
many more.
- Arbitrary-precision long integers and 30-bit precision floats.
- WiFi support.
- Sockets using modlwip.
- GPIO and bit-banging I2C, SPI support.
- 1-Wire and WS2812 (aka Neopixel) protocols support.
- Internal filesystem using the flash.
- WebREPL over WiFi from a browser (clients at https://github.com/micropython/webrepl).
- Modules for HTTP, MQTT, many other formats and protocols via
https://github.com/micropython/micropython-lib .
Documentation is available at http://docs.micropython.org/en/latest/esp8266/quickref.html.
Build instructions
------------------
You need the esp-open-sdk toolchain (which provides both the compiler and libraries), which
you can obtain using one of the following two options:
- Use a Docker image with a pre-built toolchain (**recommended**).
To use this, install Docker, then prepend
`docker run --rm -v $HOME:$HOME -u $UID -w $PWD larsks/esp-open-sdk ` to the start
of the mpy-cross and firmware `make` commands below. This will run the commands using the
toolchain inside the container but using the files on your local filesystem.
- or, install the esp-open-sdk directly on your PC, 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. Make sure
to add toolchain bin directory to your PATH. Read esp-open-sdk's README for
additional important information on toolchain setup.
If you use this approach, then the command below will work exactly.
Add the external dependencies to the MicroPython repository checkout:
```bash
$ make -C ports/esp8266 submodules
```
See the README in the repository root for more information about external
dependencies.
The MicroPython cross-compiler must be built to pre-compile some of the
built-in scripts to bytecode. This can be done using:
```bash
$ make -C mpy-cross
```
(Prepend the Docker command if using Docker, see above)
Then, to build MicroPython for the ESP8266, just run:
```bash
$ cd ports/esp8266
$ make
```
(Prepend the Docker command if using Docker, see above)
This will produce binary images in the `build-GENERIC/` subdirectory. If you
install MicroPython to your module for the first time, or after installing any
other firmware, you should erase flash completely:
```bash
$ esptool.py --port /dev/ttyXXX erase_flash
```
You can install esptool.py either from your system package manager or from PyPi.
Erasing the flash is also useful as a troubleshooting measure, if a module doesn't
behave as expected.
To flash MicroPython image to your ESP8266, use:
```bash
$ make deploy
```
(This should not be run inside Docker as it will need access to the serial port.)
This will use the `esptool.py` script to download the images. You must have
your ESP module in the bootloader mode, and connected to a serial port on your PC.
The default serial port is `/dev/ttyACM0`, flash mode is `qio` and flash size is
`detect` (auto-detect based on Flash ID).
To specify other values for `esptool.py`, use, e.g.:
```bash
$ make PORT=/dev/ttyUSB0 FLASH_MODE=qio FLASH_SIZE=32m deploy
```
(note that flash size is in megabits)
If you want to flash manually using `esptool.py` directly, the image produced is
`build-GENERIC/firmware-combined.bin`, to be flashed at 0x00000.
The default board definition is the directory `boards/GENERIC`.
For a custom configuration you can define your own board in the directory `boards/`.
The `BOARD` variable can be set on the make command line, for example:
```bash
$ make BOARD=GENERIC_512K
```
__512KB FlashROM version__
The normal build described above requires modules with at least 1MB of FlashROM
onboard. There's a special configuration for 512KB modules, which can be
built with `make BOARD=GENERIC_512K`. This configuration is highly limited, lacks
filesystem support, WebREPL, and has many other features disabled. It's mostly
suitable for advanced users who are interested to fine-tune options to achieve a
required setup. If you are an end user, please consider using a module with at
least 1MB of FlashROM.
First start
-----------
Be sure to change ESP8266's WiFi access point password ASAP, see below.
__Serial prompt__
You can access the REPL (Python prompt) over UART (the same as used for
programming).
- Baudrate: 115200
Run `help()` for some basic information.
__WiFi__
Initially, the device configures itself as a WiFi access point (AP).
- ESSID: MicroPython-xxxxxx (xs are replaced with part of the MAC address).
- Password: micropythoN (note the upper-case N).
- IP address of the board: 192.168.4.1.
- DHCP-server is activated.
- Please be sure to change the password to something non-guessable
immediately. `help()` gives information how.
__WebREPL__
Python prompt over WiFi, connecting through a browser.
- Hosted at http://micropython.org/webrepl.
- GitHub repository https://github.com/micropython/webrepl.
Please follow the instructions there.
__upip__
The ESP8266 port comes with builtin `upip` package manager, which can
be used to install additional modules (see the main README for more
information):
```
>>> import upip
>>> upip.install("micropython-pystone_lowmem")
[...]
>>> import pystone_lowmem
>>> pystone_lowmem.main()
```
Downloading and installing packages may requite a lot of free memory,
if you get an error, retry immediately after the hard reset.
Documentation
-------------
More detailed documentation and instructions can be found at
http://docs.micropython.org/en/latest/esp8266/ , which includes Quick
Reference, Tutorial, General Information related to ESP8266 port, and
to MicroPython in general.
Troubleshooting
---------------
While the port is in beta, it's known to be generally stable. If you
experience strange bootloops, crashes, lockups, here's a list to check against:
- You didn't erase flash before programming MicroPython firmware.
- Firmware can be occasionally flashed incorrectly. Just retry. Recent
esptool.py versions have --verify option.
- Power supply you use doesn't provide enough power for ESP8266 or isn't
stable enough.
- A module/flash may be defective (not unheard of for cheap modules).
Please consult dedicated ESP8266 forums/resources for hardware-related
problems.
Additional information may be available by the documentation links above.