Disable any HMI Virtual Com Port if it is enabled. Configure the USART3 to mode asynchronous and set PD8 to USART3_TX and PD9 to USART3_RX. Add
/* USER CODE BEGIN 0 */
int __io_putchar(int ch) {
HAL_UART_Transmit(&huart3, (uint8_t *)&ch, 1, 0xFFFF);
return ch;
}
main.c
Now you can printf using uart to your pc over the integrated st-link.
Make sure to end your printf calls with \n, otherwise nothing will be printed as
stdout is line buffered