Thinking about an adapter board to connect multiple ATtiny85s to a single programmer using off-the-shelf DIP parts.

Incredibly work-in-progress.

• Long ZIF socket for fast engagement on multiple chips simultaneously
• Programming is done on each chip individually
• Each chip can connect to target PCB for manual testing
• Support for both manual chip and auto/digital chip selection
• Indicators for board/chip-level statuses
• ~Chainable

• Reverse address pin switch order
• Fix ZIF footprint. Component pins are larger than regular DIP socket
• Maybe rethink IO header position

• Do I really need four discrete, per-chip pins to program? Sharing common pins and only multiplexing the minimum could simplify BOM.
• Standalone operation w/o a big computer. Raspberry Pi? SD card for storing hex?
• Queue system: load ZIF and mark ready for programming. LEDs indicate when they're ready, and they can be removed while other ZIFs are being used.
• Arbitrary pin routing to support other chips, pin counts, and number of chips per socket
• For now, intentionally not pursuing...
  • Chip switching could be done with manual switches instead of multiplexers. They'd be weird and expensive and obviously not digitally controllable.
  • Programming chips in parallel is feasible (and, anecdotally, commonplace) but require extra verification to test.
  • Could skip multiplexers and instead use multiple sets of GPIO for ICSP pins. It moves a a lot of the complexity into software, which might be nice! Cons: heavily coupled to specific tech, connecting to a target PCB less straightforward.
  • I'm using the 28 pin ZIF because that's what I have for programming the ATmega328. 32 and 40 pin ZIFs have wider pin spacings but, if I'm reading correctly, may still work for DIP8 chipss.

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