dual-controller-sync

# Dual-Controller Synchronization Guide ## When to Use This Skill Apply this skill when the user: - Has issues with I2C communication between main and camera controllers - Needs to debug the dual-ESP32 robocar architecture - Wants to monitor both controllers simultaneously - Experiences timing or synchronization issues ## Architecture Overview ``` ┌─────────────────────┐ I2C ┌─────────────────────┐ │ Main Controller │◄────────────►│ Camera Module │ │ Heltec WiFi LoRa │ │ ESP32-CAM │ │ │ │ │ │ - AI decisions │ │ - Image capture │ │ - Motor control │ │ - Vision analysis │ │ - LoRa comms │ │ - I2C slave │ └─────────────────────┘ └─────────────────────┘ ``` ## Build Both Controllers ```bash # Build main controller just robocar::build-main # Build camera module just robocar::build-cam # Or build both just robocar::build-all ``` ## Monitor Both Controllers ### Two Terminal Setup Open two terminals and monitor both: **Terminal 1 - Main Controller:** ```bash just robocar::monitor-main PORT=/dev/cu.usbserial-0001 ``` **Terminal 2 - Camera Module:** ```bash just robocar::monitor-cam PORT=/dev/cu.usbserial-0002 ``` ### Identifying Ports If unsure which device is which: ```bash ls -la /dev/cu.usbserial-* /dev/ttyUSB* ``` Look for: - Device that appears first after connecting main controller - Device that appears after connecting camera module ## I2C Communication Debugging ### Common I2C Issues | Symptom | Possible Cause | Solution | |---------|----------------|----------| | No response | Wrong address | Verify 7-bit address format | | Timeout | Missing pull-ups | Add 4.7K resistors on SDA/SCL | | Corrupted data | Speed too fast | Reduce I2C clock frequency | | Intermittent | Loose connection | Check wiring | ### I2C Address Configuration Ensure both controllers use the same address: **Main controller (master):** ```c #define CAMERA_I2C_ADDR 0x55 // 7-bit address ``` **Camera module (slave):** ```c #define I2C_SLAVE_ADDR 0x55 // Must match master ``` ### Verify I2C Wiring ``` Main Controller Camera Module SDA (21) ◄──────────► SDA (GPIO) SCL (22) ◄──────────► SCL (GPIO) GND ◄──────────► GND ``` Pull-up resistors (4.7K) on SDA and SCL to 3.3V. ## Protocol Debugging ### Expected Communication Pattern 1. Main sends command byte 2. Camera processes command 3. Camera sends response 4. Main reads response ### Debug Logging Enable verbose I2C logging in both projects: ```c esp_log_level_set("i2c", ESP_LOG_DEBUG); ``` Look for matching transactions: - Main: "Sent command 0x01 to 0x55" - Camera: "Received command 0x01" ### Timing Issues If commands arrive too fast: **Add delay between commands:** ```c i2c_master_cmd_begin(I2C_NUM, cmd, pdMS_TO_TICKS(100)); vTaskDelay(pdMS_TO_TICKS(10)); // Wait for slave to process ``` ## Flash Workflow ### Flash Both Controllers ```bash # Flash main controller first just robocar::flash-main PORT=/dev/cu.usbserial-0001 # Then flash camera (requires GPIO0 to GND) # Connect GPIO0 to GND on ESP32-CAM just robocar::flash-cam PORT=/dev/cu.usbserial-0002 # Disconnect GPIO0 from GND and reset ``` ### Development Cycle For rapid iteration: 1. Make code changes 2. Build: `just robocar::build-all` 3. Flash main: `just robocar::flash-main` 4. Flash camera (GPIO0→GND): `just robocar::flash-cam` 5. Monitor both in separate terminals ## Common Synchronization Issues ### Issue: Camera Not Responding **Symptoms:** - Main reports I2C timeout - Camera not in monitor output **Debug Steps:** 1. Verify camera is powered and running 2. Check I2C address matches 3. Verify GPIO pins for I2C slave 4. Check clock speed compatibility ### Issue: Corrupted Data **Symptoms:** - Data received but values wrong - Checksum failures **Debug Steps:** 1. Reduce I2C speed (try 100kHz) 2. Add pull-up resistors 3. Check for noise on long wires 4. Verify endianness of multi-byte data ### Issue: Timing Mismatch **Symptoms:** - Works sometimes, fails other times - Camera not ready when main sends command **Debug Steps:** 1. Add handshake mechanism 2. Increase timeout values 3. Use interrupt-based I2C on camera 4. Add ready signal GPIO ## Tools and Commands ```bash # Show system info just robocar::info # Check environment make check-environment # Clean and rebuild just robocar::clean-all just robocar::build-all # Full dev cycle for main just robocar::develop-main PORT=/dev/xxx # Full dev cycle for camera just robocar::develop-cam PORT=/dev/xxx ```