STM32F4 NUCLEO-F429ZI Unable to Communicate with HMI via RS232/RS485

QuangIoT · ‎2024-11-25

I am facing an issue connecting the STM32F4 NUCLEO-F429ZI board to an HMI screen that uses RS232 and RS485 communication standards. The HMI can communicate successfully with my computer, but the STM32 board cannot communicate with the computer except through UART3 and using a direct cable connection. This prevents me from establishing communication between the STM32 board and the HMI screen.

Could you please help me identify what might be causing this issue and how I can resolve it?

Thank you!

Andrew Neil · ‎2024-11-25

@QuangIoT wrote:

I have tested the STM32 separately with the computer, but the STM32 does not receive the messages sent from the computer.

So, as @SofLit says, you need to address that first - before adding the complications of the "HMI display"

@QuangIoT wrote:
I have tried debugging both the hardware and software.

So what, exactly, have you done? What have you observed? What have you learned about what's going on?

@QuangIoT wrote:
Communication Interfaces
RS232: Supports serial communication
RS485: For industrial environments requiring differential signaling
TTL UART: 3.3V level UART communication
Baud Rate: Configurable, typically 9600 to 115200 bps

So 3 different options for the connection - are you sure you're using the correct one, and the configuration is correct?

SofLit · ‎2024-11-25

@QuangIoT wrote:

I still have the transmission cable plugged in.

You need to provide what you are using as cable? could you please share an image please? the connection between the Nucleo and the computer?

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