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Build a No-Slot MIDI Interface on the Apple ][ Game I/O Socket

• danbmil99 6y ago
  Did similar stuff on Atari & Amiga. We actually had an app that could create SMPTE timecode on a pin of a printer port. Then we could read the timecode back (on an interrupt) and synchronize a MIDI score to a multi-track tape recorder. Oh and we used another pin to output MIDI... fun times
• dwheeler 6y ago
  I used to run my printer off my Apple II using the same kind of trick. Instead of having a separate card, I used the game IO socket and some machine code.
• dhosek 6y ago
  I just had a flashback to the challenge of finding 150ohm dual axis variable pots to have a joystick for an apple ][ because the ones that they sold at Radio Shack were 100ohm.
• twoodfin 6y ago
  Had no idea that MIDI recommended/required (?) an opto-isolator as part of the spec. Makes a ton of sense given the range (& expense!) of supporting devices and the intended use.
• dan_hawkins 6y ago
  > The signals sent on your MIDI OUT port need to drive a phototransistor inside an opto-isolator in the MIDI IN circuit. I would assume that MIDI OUT needs to drive LED in an opto-isolator.