Posted by MarkV6 on 2017-10-24 11:54

Here my non blocking getchar. You need to clear the overflow otherwise the rx available will not rise again

bool getchar(uint8_t * ch)
{
       // check for overflow and clear
	if (__HAL_UART_GET_FLAG(&huart1, UART_FLAG_ORE))
		__HAL_UART_CLEAR_FLAG(&huart1, UART_FLAG_ORE);

	if (__HAL_UART_GET_FLAG(&huart1, UART_FLAG_RXNE))
	{
		*ch = huart1.Instance->RDR & 0x1FF;
		return true;
	}

	return false;
}

And to make printf work in blocking mode:

void _write(int file, char *ptr, int len)
{
		HAL_UART_Transmit(&huart1, (uint8_t*) ptr, len, 10);
}