Hi. The lack of Serial.End() method is not critical in most cases. Its work is to deinitialize the hardware UART and release the controller pins that were connected to it.
It should be noted that the HardwareSerial class is static and calling the End() method does not free RAM. It is not difficult to add support for this method, but I would like to know how you want to use it.
問 今天剛發現arduino串口通訊居然不支持Serial.end();