Unit ACSSR U139 mode change, micropython

  • Hello,

    I start to test the Module and I could not change the mode with the Button, the module blink only 6 times red. Is there in other hack to change the mode?
    Then I tried to change the firmware with micro python but the ESP32 sends only invalid header: 0xffffffff after flashing. The ESP32 should work with the standard firmware or is there any difference?
    If I want to change the firmware back, is there a manual to flash, it?

  • Hello @ArminFriedel

    to change the mode do the following:

    • remove power
    • press and hold button
    • apply power --> RGB LED should blink rapidly
    • short press button until the RGB LED rapidly blinks in the color of the mode you want
    • confirm mode with a long press

    If you want to modify the internal firmware you need to open the case to access the standard connector to flash the internal ESP32. Check out the schematic - J1 is the programming connector.

    Standard firmware can be found here. You'll need the Espressif ESP-IDF environment to compile, link and flash.


  • There isn't a software mode select but changing modes can be a bit of a challenge.

    What I have been able to do is recorded here : https://www.hackster.io/AJB2K3/get-started-with-the-m5stack-acssr-cf960b

  • @ajb2k3 You know, Adam, I bought an ACSSR intending it to be turned on by ESP_NOW, but was gutted to find that the programming pins are not brought out.
    It works as advertised, but not like all other M5Stack products, which are very useful ESP32 devices, and infinitely programmable.
    I made an ASSumption!

  • Hello @teastain

    FYI: getting access to the programming pins isn't that hard. However if you'd like to run anything on the internal ESP32 that requires WiFi, you'd need to add a WiFi antenna. The traces are there on the board but the necessary parts are not populated.


  • @teastain That was my hope too and I was disappointed to find it controlled by an esp32 but not wifi accessible :(