UART7 problem in STM32MP157F-DK2

[bilgitay]

We are trying to read an analog value from a sensor (PF14 pin - A0 on Arduino connectors) and send it over UART (UART7 - PE7 for RX, PE8 for TX) for reading in the terminal of computer. We use M4 for this aim. Our final goal is to read the analog value over OPENAMP to be used on A7 side. But we want to be sure about the data integrity, and correctness of analog output as a first step. That's why we use UART7 through FTDI. We can read only "enclosed question marks" in the terminal. We are able to correctly read and graph analog readings with NUCLEO-STM32L432KC, using the same sampling rate and using USART1 and FTDI (although data resolution seems to be decreased significantly, compared to reading data over ST-LINK). Since ST-LINK is dedicated to A7 in STM32MP157F-DK2, it seems that it can not be used on M4 side (in Engineering Mode) for our aim.

The pin configuration in A7 dts file is as follows.

m4_uart7_pins_mx: m4_uart7_mx-0 {

   pins {

      pinmux = <STM32_PINMUX('E', 7, RSVD)>, /* UART7_RX */

         <STM32_PINMUX('E', 8, RSVD)>; /* UART7_TX */

   };

};

We would like to ask for your suggesitons.

[Olivier GALLIEN]

Hi @bilgitay​ ,

Sorry to come late on this thread.

Are you still stuck on this issue ?

Actually your question is not clear for me.

"Since ST-LINK is dedicated to A7 in STM32MP157F-DK2, it seems that it can not be used on M4 side (in Engineering Mode) for our aim."

Are you talking about STLink as debugger probe or Virtual COM Port ?

On DK2 ST-Link VCP is linked to UART4 instance only.

There's no restriction to debug M4 in engineering mode.

Which IDE are you using ?

For UART7, do you use it to receive data from the sensor / Nucleo board or to display on host console through FDTI ?

Thanks,

Olivier