charonme

Thanks! AFAIK the midi library thru requires calling the read() method in the loop which is a big problem when I need to output stuff on a slow i2c display and this results in an unacceptable huge and inconsistent latency. I've tried other...

wait no, I do need the hexinverter to provide enough current sink for the midi output

I'd like to be able to both have a HW MIDI thru and also at the same time read the input into Teensy 3.6 Can I just connect the optocoupler (U1) output to both Teensy RX1 and the output buffer (U3) like this? The 74LS157 (or CD74HCT157E) switch...

This schematic works for me, although adding a 4.7k-10k resistor to ground from pin 7 (based on this suggestion) seems to improve the rise time of the output signal. without the resistor: with the resistor: