RAK4270 UART2 problem

RAK4270 do not receive data from UART2


Details:RAK4270 module from Aliexpress. After a week of working with it, data reception via UART2 stopped working. How can I check that the input is not burned? Can I configure RX2 as GPIO-input for check?

Hi @BoolAB ,

The RX2 is configured as input (it is a receive pin).

Regarding UART2 not working suddenly, it is strange that it will suddenly get burned like you said. Anything changes/impact/stress the unit went through you can think of before it happened?

I can’t recall any changes/impacts that would cause the entry to burn out. The circuitry of the device did not change, until that moment everything worked. I wrote a small program in STM32CUBE for verification, and it confirmed that it was the UART2 reception that stopped working. Pin PA3, corresponding to RX2, works fine as a GPIO for input and output. I think I broke something in the microcontroller :frowning: Tell me please, can I use UART1 in usermode, not for RUI AT commands?

If it still works as GPIO, it is likely that the hardware is still ok. If anything will be busted, usually it is the ESD protections of the IO pins. Still, case to case basis. But if your small code works on other RAK4270 module, then probably something is not working ok in the internals of that specific module.

With UART1, are you going to use RUI or your own code? If custom, that should be ok as normal IO.

Yes, I’m also surprised that GPIO works and UART does not work. I’ll double-check.
Now UART1 in my project is only used to display debug messages via RUI_LOG_PRINTF. How can I configure it so that I can process the incoming serial stream in rui_uart_recv?