A chip-to-chip net is now resolved by (value, strength), not last-writer-
wins, so a real multi-driver bus works: many chips on one data line, only
the enabled one drives, the rest release to Hi-Z.
- busLogic.ts: 4-valued (0/1/Z/X) + drive-strength resolution. Strongest
driver wins; equal strength + opposite = X (contention); no driver = Z;
pull resistor = pull strength. modeToDrive maps VX_OUTPUT -> strong,
VX_INPUT -> Hi-Z (the rom/ram/8255 "release by input" idiom becomes real
tri-state), VX_INPUT_PULLUP/DOWN -> pull.
- busNets.ts: per-net driver registry; resolves and pushes the resolved
level into PinManager; warns once on contention.
- syntheticPins.ts: isSyntheticNetPin distinguishes bus net keys.
- ChipRuntime.ts: pin register/write/set_mode route bus-net pins through
busNets (gated by chipBusEnabled + isSyntheticNetPin); non-bus pins keep
the legacy path; dispose releases the chip's bus drivers. SPICE source
emission is skipped for bus pins (digital fast path beside SPICE).
Tests: busLogic (14), busNets (6, incl. tri-state hand-off + contention),
and the two-real-chip integration now exchanges 0xA5 through the registry.
Full suite 2074 pass with the flag off.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Fixes root cause A of the multi-chip digital bus track
(project/multichip-bus/): chip-to-chip nets were keyed per-endpoint by
syntheticChipPin(chipId, pinName), so two chips on one wire resolved to
two different PinManager keys and never shared a net.
- chipNets.ts: union-find over the wire graph mints one canonical
syntheticNetPin per net; resolveChipNetKey returns it only for pure
chip-to-chip nets (>=2 chip endpoints, no board pin). Reuses the
existing spice/unionFind.ts.
- syntheticPins.ts: add syntheticNetPin(netId), same allocator/space.
- DynamicComponent.tsx: traceDetailed consults resolveChipNetKey at
depth 0 before the chipNeighbour fallback. Board priority (rule 1) and
chip-to-component (rules 2/3) are unchanged.
- Gated behind ?chipbus=on / localStorage.velxio.chipbus (off by default).
Proof (D-008 go/no-go): __tests__/chipbus-netkey.test.ts - a byte written
on one chip's keys is visible synchronously to another via PinManager.
9 new tests; 85 resolver/PinManager/parts regression tests green flag-off.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
A custom-chip output pin wired directly to a component (LED, resistor, ...)
had no Arduino pin on its net, so the chip could drive nothing and the pin
resolved to null. Now:
- Layer A (digital): such chip pins get a stable synthetic pin number
(syntheticPins.ts). traceDetailed resolves a chip<->component net to that
shared number, so the chip's PinManager drive reaches the wired components
through the existing digital event flow. A real board pin still wins.
- Layer B (analog/SPICE): a custom-chip mapper in componentToSpice emits a DC
voltage source on each driven output pin's net (recorded in chipPinDrives by
ChipRuntime), exactly like a board GPIO, and the chip requests an electrical
re-solve when it toggles a pin (electricalResolveHook -> service.tick).
So LEDs / resistors / analog parts wired to a chip output are driven by
ngspice too.
This makes the bundled Z80 / i8080 chip examples actually animate their LEDs,
and lets any custom chip drive components, passives and analog circuits from
its own pins. Non-chip circuits are unaffected.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
David Montero Crespo