As part of our serial protocol, we need to send this pulse from time to time:
... Serial1.end(); pinMode(18, OUTPUT); digitalWrite(18, LOW); delay(500); digitalWrite(18, HIGH); delay(500); Serial1.begin(9600); ...
(Sending a pulse over the Tx1 pin)
It seems like that with the Due (It worked great with the Mega), once we call Serial1.begin again - it doesn't reset the TX1 pin status and we can no longer send anything over the serial1 port (receiving data still works).
I tried lowering the pin to LOW before calling Serial1.begin, and also changing the pinMode to different states (INPUT, INPUT_PULLUP) - but still can't send data over the serial lines.
Once I reset the board - we get back full serial functionality.
Any help will be greatly appreciated!