10 years, 3 months ago.

USB Virtual COM Port Ceases to Function after 2-4 minutes

I have my Nucleo-F103RB virtual serial port over USB working for a short period of time. Usually around 2-4 minutes it will continue to push data across to my terminal. Then serial data will stop. USB is still functions, I can program the Nucleo just fine after serial data stalls. I see data being sent by the application micro (via serial) to the STLINK micro. No error is reported by windows device manager, the COM port is still functioning as far as Windows 7 (64-bit) is concerned. But serial data coming into the STLINK to the from the application micro never makes its way through to the USB. Reprogramming the micro or resetting the micro doesn't fix it. The only way to make it work again is by unplugging the nucleo from the computer.

I installed the STLINK009 is installed in windows. If I were a betting man, I'd say there is something wrong with the STLINK driver. Anybody familiar with this issue or have ideas on what else could be tried?

I've changed the baud rate, the data being sent, the com port number. Nothing seems to have an effect on the timing of the failure. Always somewhere between 80 and 240 seconds after power-on.

This is the code I'm running:

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1. include "mbed.h"

-------- Hyperterminal configuration 9600 bauds, 8-bit data, no parity --------

Serial pc(SERIAL_TX, SERIAL_RX);

DigitalOut myled(LED1);

int main() { int i = 1; pc.baud(1200); while(1) { wait(1); pc.printf("This program runs since %d seconds.\n", i++); myled = !myled; } }

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