machine.reset() does not perform a "clean" reset on the ESP32

[asantiagod]

Hi,
After some testing using micropython on the ESP32, I've noticed that the method machine.reset() doesn't perform a "clean" reset process. By the word "clean" I mean that the MCU doesn't reset, it just seems like micropython cleans up its internal variables, but peripherals remain in the previous state.

For example, after I run the following commands, the ledPin remains on after running the machine.reset() command.

>>> import machine
>>> ledPin = machine.Pin(2, machine.Pin.OUT)
>>> ledPin.value(1)
>>> machine.reset()
MicroPython v1.25.0-preview.114.gbdda91fe7.dirty on 2025-02-2T
Type "help()" for more information.
>>>

The documentation says that machine.reset() command is similar to pushing the external RESET button, but it doesn't seem to be the case.

I'll be grateful if someone can tell me how to workaround the issue.

NOTES:

• I'm working with a ESP32-WROOM-32U
• I'm building micropython from the master branch in the official repository (commit bdda91f)

[davefes]

Unfortunately, "similar" is not the same as exactly. There are many situations where a full poweron reset is required:

• hardware peripherals, ie camera, UART (?)
• probably other hardware interfaces

Hadn't noticed your LED case.

A useful test is to measure GPIO state after a machine.reset() and then after a full power_on reset.

My work-around: https://github.com/davefes/ESP32-CAM-Micropython/blob/main/ESP32_CAM_poweron.pdf

[asantiagod]

Thanks for your reply.

I've measured the GPIO after a machine.reset() and I observed that its state remains unchanged, however, the expected behavior is for the GPIO to switch to input mode after the reset process (both external reset and software reset using the Arduno Framework).

Thanks for sharing your workaround. Unfortunately, the hardware of my project has already been developed and works fine with C/C++ code (ESP-IDF + Arduino), so I belive the solution can be a software approach rather than a hardware modification.

I really appreciate your help and insights on this issue!