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UART GPIO repeately dies

Posted: Mon Feb 03, 2020 7:16 pm
by Awsmtek
Hello!
I have custom board with ESP32wroom32 module.
Application uses UART0 for logging and UART1 for configuration.
I left device on test bench for a week. It measured temperature and sent to my backend every minute and reported about it to Raspberry Pi using UART0.
UART0 has been connected with USB to SERIAL adapter CP2102. The levels were 3.3V.
After a week (just now) I have seen that CP2102 adapter TXD LED is constantly light up.
So this mean UART0 RX pin is constantly LOW.
As a result - I can't connect to internal bootloader to flash the module.

BTW UART1 was not connected at all, and it stopped working too. There is constant LOW level on RX pin.
Before I left device on test bench - I have reconfigure it using UART1. So I am pretty sure it was working.
UART1 is connecting to the PC using on-board USB to UART adapter CH340G set up for 3.3V levels.

On first time I have launched this board CH340G was set up for 5V and TX pin on UART1 was stopped working (so I wired it to other GPIO)

I think it can be latch up event or something like that.
I would appreciate any assistance can help to find a reason of this issue.