Helpful Footprint References:
accidentally forgot to connect the key common on the multiplexer to the Teensy - so gotta manually connect it on the PCB board
nothing connected :p
Source: https://www.pjrc.com/teensy/td_libs_MIDI.html
Optocoupler
This is an optocoupler.
Optocoupler: Always refer to the data sheet to figure out what footprint to use (if designing on a PCB board) There’s many different kinds of optocouplers too, this is just an example.
This website is a helpful source: https://hackaday.com/2018/05/09/optocouplers-defending-your-microcontroller-midi-and-a-hot-tip-for-speed/
https://hackaday.com/2018/05/09/optocouplers-defending-your-microcontroller-midi-and-a-hot-tip-for-speed/