1、How do I read the data received by the serial port in polling mode
I tried it, but I thought it might not work, because the read function only returns successes and failures, not the actual read length
2、Similarly, when the FIFO function is enabled, the maximum number of received data is 16 bytes. If it is less than 16 bytes, we still cannot know the actual number of received data, so we can only receive one byte by one, and cannot read multiple bytes at a time, nor can we read the data received by the serial port in polling