Hard resetting issue

[balix53]

Hi,

My company works on several ESP32 based projects and we noticed an issue when using the ESP IDF scripts/tools to flash and reset the development kits.
What is happening is that from time to time the device will not be reset when using a flash command and we cannot identify what could cause such issue.

For example on ESP32-S2 with ESP IDF v4.2.2 we use the following command to flash and reset dev kits:

Code: Select all

python %IDF_PATH%\components\esptool_py\esptool\esptool.py -p COM8 -b 921600 --before default_reset --after hard_reset --chip esp32s2  write_flash --flash_mode dio --flash_size detect --flash_freq 80m application.bin

And then the command will show a successful flash of the device and the line "Hard resetting via RTS pin...". Then nothing appears on the serial output for the logs, the device needs to be restarted manually.

The same issue can appear on a ESP32 WROVER dev kit with ESP IDF v3.3.4.

Since it is not consistent we do not know how we can reproduce and why it happens.

Is there any known issue that could cause this?

Regards,

Benjamin

[ESP_Sprite]

The hard reset generally is done via a two-transistor network on the DTR/RTS pins of the USB-serial converter that pull down the EN line of the ESP32. Perhaps it can be insightful to scope out those signals while you're resetting the board? Possibly they are marginal, leading to issues with some boards but not with others.

[balix53]

Thanks for the tip. We will try to check that and come back to you when we have more info.