Steve Herndon

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8 years, 8 months ago.  This question has been closed. Reason: Off Topic

UART loopback test

Hello,

I'm new to mbed and embedded development and trying to get a simple UART loopback working. I'm using the Nucleo-F411RE and have shorted D0 to D1. My code to simply echo a character on UART is below.

UART Loopback test

#include "mbed.h"

Serial pc(D1, D0);

int main()
{
    pc.putc('a');
    
    char ch = pc.getc();
}

The above code will freeze on the pc.getc() statement. When I use offline tools it is blocked on serial_readable(). This appears to be similar to Rafael's issue in https://developer.mbed.org/questions/75851/Serial-loopback-Nucleo-F446RE.

I've also attached an image of how I've setup my loopback in case I've done that improperly. I'd appreciate the help for whatever I've done improperly.

Thanks /media/uploads/herrdrfred/uart-loopback.jpg

-- 2/28 edit - Upon further research I found that UART2 is dedicated to USB and not really usable. I moved the code and jumper to UART1 and it worked as expected.