Python on MicroControllers

This serves as my todo list on setting up MicroPython on ESP 8266 and ESP 32 micro controllers.

  1. Identify your Chip 
    ❯ esptool.py --port /dev/tty.usbserial-140 flash_id
esptool.py v2.8
Serial port /dev/tty.usbserial-140
Connecting....
Detecting chip type... ESP8266
Chip is ESP8266EX
Features: WiFi
Crystal is 26MHz
MAC: a0:20:a6:17:52:a5
Uploading stub...
Running stub...
Stub running...
Manufacturer: e0
Device: 4016
Detected flash size: 4MB
Hard resetting via RTS pin...

    The Detected flash size: 4MB indicates we can use the latest regular MicroPython image.

  2. Erase flash memory 
    ❯ esptool.py --port /dev/tty.usbserial-140 erase_flash
esptool.py v2.8
Serial port /dev/tty.usbserial-140
Connecting....
Detecting chip type... ESP8266
Chip is ESP8266EX
Features: WiFi
Crystal is 26MHz
MAC: a0:20:a6:17:52:a5
Uploading stub...
Running stub...
Stub running...
Erasing flash (this may take a while)...
Chip erase completed successfully in 11.2s
Hard resetting via RTS pin...
  3. Deploy MicroPython 
    ❯ esptool.py --port /dev/tty.usbserial-140 --baud 460800 write_flash --flash_size=detect 0 ~/Downloads/esp8266-20220618-v1.19.1.bin
esptool.py v2.8
Serial port /dev/tty.usbserial-140
Connecting....
Detecting chip type... ESP8266
Chip is ESP8266EX
Features: WiFi
Crystal is 26MHz
MAC: a0:20:a6:17:52:a5
Uploading stub...
Running stub...
Stub running...
Changing baud rate to 460800
Changed.
Configuring flash size...
Auto-detected Flash size: 4MB
Flash params set to 0x0040
Compressed 634844 bytes to 419808...
Wrote 634844 bytes (419808 compressed) at 0x00000000 in 10.5 seconds (effective 485.9 kbit/s)...
Hash of data verified.
Leaving...
Hard resetting via RTS pin...
  4. Enable Wifi and connect the MCU to your WLAN
    The default REPL is available via serial connection.
    We’ll use this serial connection to setup WiFi.
    I use screen here - but any terminal emulator should do: 
    > screen /dev/tty.usbserial-140 115200
  5. Press the return key until you see this: 
    >>>
  6. Configure WLAN access
    Replace "<AP_name>" and "<password>" with your values… 
    >>> import network
>>> sta_if = network.WLAN(network.STA_IF);
>>> sta_if.active(True)
>>> sta_if.connect("<AP_name>", "<password>")
>>> sta.if.isconnected()

    The last statement should return True.

  7. Lets find out the device IP: 
    >>> sta_if.isconnected()
True
>>> print(sta_if.ifconfig())
('192.168.178.66', '255.255.255.0', '192.168.178.1', '192.168.178.1')
  8. Enable WebRepl
    Once the Board joined your network it’s time to use the webrepl. 
    >>> import webrepl_setup
WebREPL daemon auto-start status: disabled
Would you like to (E)nable or (D)isable it running on boot?
(Empty line to quit)
> e
To enable WebREPL, you must set password for it
New password (4-9 chars): itzelbritzel
Confirm password: itzelbritzel
Changes will be activated after reboot
Would you like to reboot now? (y/n) y

    Answering y to the last question leads to somethong to this:

    Would you like to reboot now? (y/n) y
>>>
 ets Jan  8 2013,rst cause:2, boot mode:(3,3)
load 0x40100000, len 30720, room 16
tail 0
chksum 0xba
load 0x3ffe8000, len 996, room 8
tail 12
chksum 0x2c
ho 0 tail 12 room 4
load 0x3ffe83f0, len 1080, room 12
tail 12
chksum 0x43
csum 0x43
����'�{��o<�l$ld`c��|s�d�g��'�d`��r�$�d�l`��s�l�l�l`��;�d���l$`rdǃ;$ğ�#Č#|dc��#<��Č$lb��o�g��lo���$�$l���l`�'����cld쌏c���cl�#{$sdr�g����b���l��l���d���l�c��'�߀�#���$�$���d���WebREPL daemon started on ws://192.168.4.1:8266
WebREPL daemon started on ws://0.0.0.0:8266
Started webrepl in normal mode
MicroPython v1.19.1 on 2022-06-18; ESP module with ESP8266
Type "help()" for more information.

    Verify Micropython persisted your WiFi credentials:

    ...
MicroPython v1.19.1 on 2022-06-18; ESP module with ESP8266
Type "help()" for more information.
>>> import network
>>> sta_if = network.WLAN(network.STA_IF)
>>> sta_if.isconnected()
True
>>> sta_if.ifconfig()
('192.168.178.66', '255.255.255.0', '192.168.178.1', '192.168.178.1')

    Since WebREPl uses websockets you need to use the WebRepl Client. I recommend cloning it from GitHub and run it on you local machine. Just open webrepl.html in your brower.

    Ensure to use either file: protocol or http:.

We’re done :-)

In case of trouble please have a look at the excellent documentation here

The webrepl repo contains a a neat tool to copy files to/from the MCU:

❯ webrepl_cli.py -p itzelbritzel awesome-app.py 192.168.178.66:/awesome-app.py
op:put, host:192.168.178.66, port:8266, passwd:itzelbritzel.
awesome-app.py -> /awesome-app.py
Remote WebREPL version: (1, 19, 1)
Sent 895 of 895 bytes

A great alternative to using the webpage. (see webrepl_cli.py --help for details)