Replaces the per-peripheral ad-hoc `_ledc_gpio_map` cache with a
proper signal-routing abstraction that mirrors the ESP32 SoC's
IO_MUX + GPIO Matrix exactly. Same idea as real silicon: signal
sources (LEDC channels, RMT, MCPWM, ...) → 40-entry routing table
→ GPIO pins.
Motivation (from user bug report in
velxio.dev/project/5218f9e3-136d-43b3-bba1-6cebde21e1a4): two
ESP32 servos on a solar-tracker visibly oscillated between two
positions instead of moving smoothly when the user changed LDR
sliders. Commit 77bf897 patched it (per-channel gpio memo +
broadcast guard) but the user requested a proper hardware-fidel
architecture, not patches.
Backend:
* `app/services/signal_router.py` — SignalRouter class. Forward
index (gpio → signal_id) + reverse index (signal_id → set of
gpios). `replace_snapshot()` returns the diff for the polling-
fallback path; future C plugin hook becomes a push without
touching this code.
* `app/services/esp32_signals.py` — Signal id constants from
ESP32 TRM (LEDC HS 72-79, LS 80-87) + `ledc_signal_for_channel()`
helper.
* `app/services/esp32_worker.py` — `_ledc_gpio_map` is gone;
`_refresh_ledc_gpio_map` replaced by `_refresh_signal_routing`
which emits `gpio_routing {gpio, signal_id}` events on diff.
The 0x5000 LEDC callback and the LEDC poll thread now emit
`ledc_duty {channel, duty_pct}` (canonical, no gpio) alongside
the legacy `ledc_update {channel, duty, gpio}` for back-compat
during rollout.
Frontend:
* `simulation/SignalRouter.ts` — 1-to-1 TS mirror of the Python
class. Same forward + reverse index; same `pinsForSignal` /
`updateRouting` / `clearRouting` API.
* `simulation/esp32-signals.ts` — Signal id constants, mirror
of the Python module.
* `simulation/Esp32Bridge.ts` — new `onLedcDuty`, `onGpioRouting`,
`onGpioRoutingClear` callbacks; handlers for the new event types.
* `store/useSimulatorStore.ts` — `makeLedcDutyHandler` looks up
pins via `router.pinsForSignal(ledcSignalForChannel(channel))`
and dispatches per pin. `makeGpioRoutingHandler` /
`makeGpioRoutingClearHandler` keep the mirror in sync. Per-board
`signalRouterMap` parallels `pinManagerMap` in lifecycle.
`makeLedcUpdateHandler` (and its memo workaround from 77bf897)
stays wired for back-compat during rollout; removed in a
follow-up commit once prod is verified stable on the new path.
Tests:
* `test/backend/unit/test_signal_router.py` (20 tests) covers
update/clear semantics, idempotency, multi-pin routing,
snapshot diff, channel↔signal-id helpers, and the multi-servo
regression scenario.
* `frontend/src/__tests__/SignalRouter.test.ts` (17 tests) is the
mirror — same scenarios on the TS side.
* `frontend/src/__tests__/esp32-multi-servo-gpio-matrix.test.ts`
(6 tests) drives the end-to-end SignalRouter handler pipeline,
asserts that two servos on GPIO 13/12 via LEDC channels 0/1
move independently (no mirroring), that re-routing carries
cleanly, and — critically — that `PinManager.broadcastPwm` is
never called.
Totals: +700 LOC, 1876 frontend tests pass (was 1853), 278 backend
unit tests pass (was 259).
Docs: ESP32_EMULATION.md §9.2 rewritten with the new architecture
diagram + a runbook for adding future peripherals through the
SignalRouter.
The C plugin hook in qemu-lcgamboa that would push gpio_out_sel
writes synchronously (eliminating the polling race window entirely)
is the next step — kept as a follow-up because the polling-fallback
path here already resolves the routing before each duty event
fires, so the bug is fixed end-to-end. The plugin work removes the
race condition fundamentally.
davidmonterocrespo24