Fixes the user-reported bug where two RPi Pico W boards wired GP0↔GP1
running SerialPassthrough don't communicate. Replaces the broken
broadcast-style cross-board logic in addBoard (only routed AVR↔Pi3B,
ignored wires entirely, no RP2040↔anything path) with a wire-aware
Interconnect singleton.
Architecture: digital pin transitions are the lowest-common-denominator
abstraction. Each simulator's hardware peripherals (UART/I2C/SPI) and
bit-banging libraries (SoftwareSerial, software I2C) decode the
transitions naturally — propagate the pin and the protocols come for
free. For cross-process boards (ESP32 backend QEMU, Pi3B QEMU) a
byte-level shortcut is additionally enabled on hardware-UART pin
pairs to handle high-baud links over WebSocket latency.
Implementation:
- New simulation/Interconnect.ts singleton subscribes to wire/board
changes via the Zustand store. Handlers per tier: browser-sim →
pinManager.onPinChange, ESP32 → Esp32Bridge.sendPinEvent, Pi3B →
bridge.sendPinEvent. Re-entrancy guard via per-(board,pin) Set.
- New utils/boardProtocols.ts classifies pins (uart-tx, i2c-sda, etc.)
per board kind, used as optimization hint for the byte shortcut.
- types/wire.ts: added signalType field, exports WireSignalType /
WireColorMap (fixes a pre-existing TS import error in wireColors).
- Deleted the bridgeMap/simulatorMap broadcast forEach blocks in
addBoard. Initial board + future boards register with Interconnect
via setInterconnectRuntime + store subscription.
- PinManager.resetPinStates() helper for test isolation.
Tests (16 new files, 96 tests, all passing):
- Per-pair × per-protocol matrix: dual-arduino-digital,
dual-pico-digital, arduino-pico-digital, triple-pico-digital-chain,
dual-arduino-hw-uart, dual-arduino-software-serial,
arduino-pico-mixed-uart, arduino-esp32-uart, dual-esp32-uart,
pi3-pico-uart, arduino-pico-i2c, arduino-arduino-spi,
interconnect-routing, dual-arduino-multi-protocol (UART+I2C+SPI+
digital + concurrent), dual-pico-multi-protocol (UART0+UART1 alt+
I2C0+I2C1+SPI0+digital + 3-Pico star topology)
- Updated dual-pico-serial-passthrough to assert correct behaviour
- Backend test/multi_board_esp32/test_dual_esp32_serial.py for two
real QEMU instances (skip-graceful when lcgamboa lib absent)
Verified: 1107/1107 tests pass, zero regressions, vite build OK.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
David Montero Crespo