Do you still have the master doing
Serial.write("3");
Because that string "3" would send 2 bytes: '3' and a terminating NULL (as values 51 then 0 ).
You want to
Serial.write('3');
Do you still have the master doing
Serial.write("3");
Because that string "3" would send 2 bytes: '3' and a terminating NULL (as values 51 then 0 ).
You want to
Serial.write('3');