With the DaisySeed, I’ve noticed that I cannot read from USART_1 (pins 14,15) unless the micro usb cable is connected. For my project, I’d like to simply power the DS from the Vin pin, while polling the USART_1 for incoming messages. Is this possible??
That doesn’t sound right. For example, KXMX Bluemchen uses serial MIDI, and is powered by Eurorack, with nothing plugged in on Daisy Seed USB.
Do you have AGND connected to DGND?
I have it working like you described. Using the midi handler of libDaisy.