Closes the remaining gaps in cross-board I2C so any topology of
supported boards (Uno↔ESP32, two ESP32s, Uno↔Uno↔Uno, ESP32-C3
connected to anything, etc.) works end-to-end with all I2C
components including write-only sinks (SSD1306, PCF8574, LCD-I2C).
Implementation (6 phases):
1. **BFS routing in I2CBusManager**: connectToSlave + handleExternalConnect
walk the bridge graph with a visited Set so multi-hop chains
(A↔B↔C with the device on C) resolve transparently. A new
forwarder-device shim is installed at intermediate hops so the
existing handleExternalWrite/Read/Stop machinery routes
through without per-method visited tracking.
2. **Per-peer proxy ownership in Esp32BridgeShim**: replaces the
global _proxiedAddrs Set with _proxiedByPeer Map so concurrent
bridges to the same ESP32 (e.g. wired to both Uno and Pico)
don't wipe each other's proxies on teardown. Interconnect's
per-wire teardown calls clearProxiesForPeer(peerBus) instead of
clearAllProxies.
3. **BFS-aware proxy sync**: syncProxyFromPeer now walks the peer
bus + its transitive bridges, so an ESP32 sees devices on
boards two or more hops away. _peerDeviceLookup keeps a flat
addr → device map for write-forwarding and resync.
4. **Periodic resync (250 ms)**: Esp32BridgeShim runs a setInterval
while any proxy is live, re-dumping each device with
dumpRegisters() and pushing updateProxyI2c only when an XOR-
stride hash changes. This keeps RTC time advancing visible to
ESP32 firmware without flooding the WS pipe with static
calibration dumps. Hash is primed during initial sync so the
first tick doesn't push a redundant identical buffer.
5. **Write-forwarding ProxySlave → peer**: backend ProxySlave
buffers write bytes during the transaction and emits a
`proxy_i2c_complete` event on STOP / repeated-START. Frontend
Esp32Bridge dispatches the event to a new onProxyI2cComplete
callback; the shim replays the byte sequence on the actual
peer I2CDevice via writeByte() + stop(). Makes ESP32 firmware
writes to peer SSD1306 actually repaint the OLED, peer PCF8574
latch updates, peer I2CMemoryDevice register mutations propagate.
6. **ESP32-C3 routed as bridge**: Interconnect.isBrowserSim no
longer claims c3/xiao-c3/c3-supermini — they were already
going through Esp32Bridge per the store's ESP32_RISCV_KINDS
routing, but Interconnect was treating them as browser sims
which broke proxy install. isEsp32Bridge now correctly
includes c3 family + ESP32-S3 + Arduino Nano ESP32.
Defensive: addBoard now disposes any existing shim's proxies
before overwriting simulatorMap entry so test reruns don't leak
timers.
Tests:
- 4 BFS multi-hop tests (i2c-multi-board-slave-gap.test.ts)
- 11 cross-board scenarios + per-peer + write-forward + resync
(i2c-esp32-multiboard-bridge.test.ts)
- 1 real-firmware E2E for write-forward via QEMU (compile +
load + observe proxy_i2c_complete arriving with the byte)
- New sketch fixture: esp32_i2c_write_to_peer.ino
Result: 90 test files / 1295 tests pass / 0 fail.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
- Implemented `i2c-esp32-real-firmware.test.ts` to test ESP32 I2C communication via backend and WebSocket.
- Created `load-example-transitions.test.ts` to ensure proper loading of examples between board-less and board-based contexts.
- Added `CircuitVerificationModal.tsx` to display circuit verification results before running simulations.
- Developed `circuitVerifier.ts` to perform pre-flight checks for circuit safety, identifying potential issues like short circuits and component overloads.
- Introduced minimal ESP32 I2C master sketch `esp32_i2c_writer.ino` for testing I2C transactions.
- Implemented Bmp280Element as a custom web component for the BMP280 barometric sensor, including SVG representation and pin configuration.
- Created CircuitPreview component to render circuit thumbnails using SVGs of components, including support for various boards and components.
- Added a script to generate SVG files from wokwi-elements, ensuring proper formatting and structure for reliable rendering.
- Introduced a test HTML generation script to visualize component SVGs.
- Updated the threshold for switching to data mode in MPU6050Slave from 2 to 3 WHO_AM_I reads to ensure correct chip identification.
- Enhanced comments in the code to clarify the sequence of I2C events during initialization.
- Added a new test file `test_mpu6050_emulation.py` to validate the MPU6050Slave state machine and ensure it handles the full Adafruit_MPU6050::begin() event sequence correctly.
- Updated existing tests to reflect the changes in the I2C handling logic.
- Modified `components-metadata.json` to update the generated timestamp.
- Marked submodules `rp2040js` and `wokwi-elements` as dirty to reflect local changes.
- Introduced I2C_SENSOR_MAP for pre-registering I2C sensors in the simulator store.
- Implemented I2C slave state machines for MPU6050, BMP280, DS1307, and DS3231 sensors in esp32_i2c_slaves.py.
- Added unit tests for I2C slave functionality covering BMP280, DS1307, DS3231, and I2CWriteSink.
- Updated the simulator store to handle I2C address resolution and sensor data management.
- Marked submodules as dirty in wokwi-libs for rp2040js and wokwi-elements.
David Montero Crespo