The chip-output board-less path existed (chipPinDrives -> SPICE voltage sources
-> LEDs). The INPUT direction was missing: a chip pin wired to a pushbutton had
its net solved by ngspice, but nothing fed that net's state back to the
PinManager key the chip reads via vx_pin_read. So a board-less chip could light
LEDs but never read a button (verified: i8080 counter stayed at 0 on press).
connectChipInputsToSolve subscribes to the electrical store and, after each
solve, thresholds every wired chip input pin's net voltage to HIGH/LOW and
triggerPinChange()s the chip's synthetic pin — updating getPinState (polling)
and firing onPinChange edges. Pins the chip is actively driving are skipped so
it never fights its own outputs. Hooked alongside connectAnalogInputsToMcu in
start.ts. Solver-agnostic; reads only the electrical store shape.
Also gives the board-less button examples a pull-down on each chip BTN pin so
they read a clean LOW when open (a button-to-VCC floats HIGH otherwise):
i8080-button-counter (2) and i8080-killbits (8).
- new connectChipInputsToSolve.ts; start.ts wiring.
- examples-retro-intel: pull-down resistors + wires for the button examples.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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