Serial port on arduino DUE stops sending data if not connected to PC

Projects Networking, Protocols, and Devices
1

Hi,

I’m using a MIDI shield (sparkfun GitHub - sparkfun/MIDI_Shield: Midi shield product 9595, available from SparkFun Electronics ) with arduino DUE to host a monome and make it send MIDI without a computer (full project GitHub - kaosbeat/monardaxo: monome - arduino - axoloti > standalone setup )
This works as long as I upload the patch from the computer. When I start just using a power supply, the receiving side works (midi receive) but sending midi fails. The TX led does not blink, no midi is sent.
For some reason I need to enable the USB port serial interface? I don’t know how to do this, or to trick the arduino in to thinking it should send data. It should work on pin 0/1

I’m enabling this port using:

’’’
MIDI_CREATE_INSTANCE(HardwareSerial, Serial, MIDI);
’’’

And like I said, this works, whenever connected to a PC (programming port on the DUE side) but not when connected using a usb power supply on the same port.

2

And like I said, this works, whenever connected to a PC (programming port on the DUE side) but not when connected using a usb power supply on the same port.

If you aren't connecting the RX/TX lines, too, where do you expect to send the data to?

3

If you connect the power supply, wait a couple seconds, then press and release the RESET button, does it start? My Due doesn't want to start if the serial monitor from my PC doesn't reset it when I connect.

4

@PaulS I want to send the data to the MIDI port, connected to pins 0/1. This works while connected to a PC serial monitor, with the data being duplicated to the midi port. This btw works fine on an arduino UNO when not connected to a PC but I need the host USB port as well.
@SurferTim no luck with the reset. Even worse, when it works, leaving the PC connected will stop the midi sending (and serial) when pressing reset.