README

This program is a configurable USB to 2x serial MIDI adapter. It connects to an
USB host via the USB connector of the Raspberry Pi Pico on one side and to up to
two MIDI devices with serial interface via GP0 (UART0 TX)/GP1 (RX) and/or GP4
(UART1 TX)/GP5 (RX) on the other side. MIDI messages/events, received on one of
the interfaces (USB, UART0, UART1), will be converted and send out on all other
interfaces by default. The LED on the Raspberry Pi Pico board flashes, when MIDI
data is exchanged.

The program is configurable and can support more complex MIDI functions (e.g.
note transpose, channel or velocity changes, note to chords). You need some
basic C/C++ knowledge and have to edit the function midi_task() in the file
main.cpp for that purpose. For example the following code transposes all MIDI
note events, which were received from USB by one octave up and sends them out to
both serial interfaces (UART0 and UART1):

void midi_task (void)
{
	USB.Update ();
	UART0.Update ();
	UART1.Update ();

	CMIDIMessage Msg;

	if (USB.Read (&Msg))
	{
		if (Msg.Type () == 0x90 || Msg.Type () == 0x80)
		{
			Msg.Param1 (Msg.Param1 () + 12);
		}

		UART0.Write (Msg);
		UART1.Write (Msg);
	}

	if (UART0.Read (&Msg))
	{
		// no action here
	}

	if (UART1.Read (&Msg))
	{
		// no action here
	}
}

Please see the file midi_message.h for the implemented methods to get and set
the different data fields of a MIDI message.

The MIDI adapter receives USB MIDI events from all virtual MIDI cables, and it
sends USB MIDI data to the virtual MIDI cable zero. MIDI system exclusive
messages will be ignored.

The Raspberry Pi Pico is powered via USB, the VSYS or VBUS pins must NOT be
connected!