I am trying to understand how the serial ports are configured on the due board. Please correct me if i'm wrong, but to my understanding, the due has:

  • Four separate serial ports ("serial", and "serial 1-3"), each with SX and TX pin functions
  • A USB port paired with serial, simultaneously sending and receiving data from the serial function via USB protocol

I'm currently sending MIDI data over serial1 with the required baud rate of 31250. I want to configure another serial function (assumingly with a different baud rate to match the IDE serial monitor) in order to monitor Serial.print messages simultaneously for debugging.

In setup():

Serial1.begin(31250);  //MIDI baud rate

and then, in a for loop i want to monitor each value i in the array loop1[i]):

Serial.print(String(loop1[i]) + " ");

However, i can't seem to make it work... My question is, is it possible to transmit the MIDI data via serial, in parallel with serial.print data with a separate serial function?

  • you should show your code. didn't you forget Serial.begin()?
    – Juraj
    May 27, 2018 at 9:39
  • Added some code
    – Erik
    May 27, 2018 at 10:40

1 Answer 1


You can't use MIDI on Serial and use Serial.print at the same time. You can though use MIDI on Serial1 and use Serial.print at the same time (or Serial2 etc).

  • I am using midi on Serial1. Tried different variations of sending MIDI on Serial2, combined with Serial.print, Serial1.print or Serial3.print. No luck though...
    – Erik
    May 27, 2018 at 10:02
  • Then there must be something else fundamentally wrong with your sketch.
    – Majenko
    May 27, 2018 at 10:05
  • Yeah, i have now been able to use Serial and Serial1 simultaneously. Your feedback answers my original question. Will look more into the function that i want to debug.
    – Erik
    May 27, 2018 at 10:21

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