[dougg3]

The schematics for the multitap are out there in the SNES developer manual [1]. I actually made one on a breadboard for fun [2] and eventually turned it into a PCB. It's a pretty simple circuit with an analog mux and some tri-state buffers.

[1] https://archive.org/details/SNESDevManual/book2/page/n385/mo...

[2] https://www.downtowndougbrown.com/2013/04/homebrew-snes-4-pl...