simon
b592401e78
Expand main/README with master/slave overview, boot config, protocols, and build notes; point goTool README at the full system doc. Co-authored-by: Cursor <cursoragent@cursor.com>
248 lines
8.0 KiB
Markdown
248 lines
8.0 KiB
Markdown
# Powerpod firmware
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ESP32-S3 firmware for Powerpod nodes. Master and slave devices run the **same binary**; role and ESP-NOW network are selected at boot via DIP switches and an I2C IO expander.
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## System overview
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```
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┌─────────────┐
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│ PC │
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│ (goTool) │
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└──────┬──────┘
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│ UART1 (921600)
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│ framed commands + protobuf
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┌──────▼──────┐
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│ MASTER │
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│ ESP32 │
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└──────┬──────┘
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│ ESP-NOW (WiFi channel = network ID)
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┌────────────┼────────────┐
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│ │ │
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┌──────▼──────┐ ┌───▼────┐ ┌─────▼─────┐
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│ SLAVE │ │ SLAVE │ │ SLAVE │
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└─────────────┘ └────────┘ └───────────┘
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```
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| Role | UART to PC | ESP-NOW |
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|--------|------------|---------|
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| Master | Yes — command handler, protobuf replies | Broadcasts discover; collects slave info |
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| Slave | No | Responds to discover with slave info |
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Planned: master forwards aggregated `ClientInfo` to the PC over UART (`CLIENT_INFO` in `uart_messages.proto`).
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## Boot configuration
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Read in `app_main()` before subsystems start. Stored in `app_config_t` (`app_config.h`).
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| Setting | Source | Notes |
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|-----------|--------|--------|
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| `master` | GPIO `DIP_MASTER` (pin 4) | Low = master, high = slave |
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| `network` | I2C IO expander `0x20`, port bits (nibble reversed) | Value 1–8 → ESP-NOW WiFi channel 1–8 |
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| `running_partition` | OTA API | Active partition label |
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Pins (`powerpod.h`):
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| Signal | GPIO |
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|--------|------|
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| DIP master | 4 |
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| I2C SCL | 5 |
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| I2C SDA | 6 |
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| UART TX | 3 |
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| UART RX | 2 |
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| LED ring | 7 |
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Startup order:
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1. Read DIP + IO expander → `app_config`
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2. `esp_now_comm_init(&app_config)` — WiFi + ESP-NOW
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3. `led_ring_init()`
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4. **Master only:** command queue, UART, registered commands (e.g. VERSION)
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## ESP-NOW discovery
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Implementation: `esp_now_comm.c` / `esp_now_comm.h`.
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WiFi is brought up in STA mode (no AP association). Channel = `app_config.network` (clamped to 1–13).
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### Air protocol (compact binary, not protobuf)
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| Byte | Field |
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|------|--------|
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| 0 | Magic `0xA1` |
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| 1 | Message type |
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| 2 | Network ID (must match local config) |
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| 3+ | Type-specific |
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| Type | Value | Direction | Purpose |
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|------|-------|-----------|---------|
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| `DISCOVER` | 1 | Master → broadcast `FF:FF:FF:FF:FF:FF` | Master is searching for slaves |
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| `SLAVE_INFO` | 2 | Slave → master | Slave registration |
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`SLAVE_INFO` payload (after header bytes 0–2):
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| Field | Type | Description |
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|-------|------|-------------|
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| `mac` | 6 bytes | Slave WiFi MAC |
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| `version` | uint32 | `POWERPOD_FW_VERSION` (default 1) |
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| `slave_id` | uint32 | Currently last byte of MAC |
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| `available` | uint8 | 1 = available |
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| `used` | uint8 | 0 = unused |
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**Master:** task `espnow_disc` sends `DISCOVER` every **500 ms** on the configured network. Logs `slave joined id=… mac=… ver=…` when a new slave is seen (up to 16 entries).
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**Slave:** on matching `DISCOVER`, unicast `SLAVE_INFO` back to the master source MAC.
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Monitor via USB-JTAG (`/dev/ttyACM0`) while using a USB-serial adapter on **GPIO2/3** (`/dev/ttyUSB0`) for UART — they are different interfaces.
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## UART (master only)
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Hardware: **UART1**, **921600** baud, **TX = GPIO3**, **RX = GPIO2** (adapter TX → ESP RX, adapter RX → ESP TX).
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### Frame format
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| Field | Value |
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|-------|--------|
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| Start | `0xAA` |
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| Length | 1 byte, payload size 1–252 |
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| Payload | `length` bytes |
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| Checksum | XOR of all payload bytes |
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| Stop | `0xCC` |
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### Command handler payload
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| Offset | Meaning |
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|--------|---------|
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| 0 | Command ID (`MessageType` / `msg_id`) |
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| 1… | Arguments (handler receives bytes after ID only) |
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Example VERSION request: single-byte payload `03` → frame `AA 01 03 03 CC`.
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Logging:
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- `[UART] received message cmd=0x… len=…`
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- `[CMDH] trigger command VERSION (0x03)` (or other name from `message_type_name()`)
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## Command handler
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Generic dispatch for host commands (UART today; `msg_post()` for in-firmware sources later).
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```
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UART → generic_msg_t queue → vCmdDispatcherTask → registered handler
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```
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| API | Description |
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|-----|-------------|
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| `init_cmdHandler(queue)` | Start dispatcher task (priority 5) |
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| `msg_register_handler(id, cb)` | Register callback; max 32 handlers |
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| `msg_post(id, data, len)` | Enqueue from firmware (e.g. future ESP-NOW → PC path) |
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```c
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typedef void (*msg_callback_t)(const uint8_t *data, size_t len);
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```
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Init order on master:
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```c
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cmd_queue = xQueueCreate(10, sizeof(generic_msg_t));
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init_cmdHandler(cmd_queue);
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init_uart(cmd_queue);
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cmd_version_register();
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```
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## Protobuf (`proto/uart_messages.proto`)
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Host and master speak nanopb-encoded `UartMessage` inside UART frames (byte 0 = `MessageType`, bytes 1… = encoded message).
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| ID | Name | Status |
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|----|------|--------|
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| 3 | `VERSION` | Implemented (`cmd_version.c`) |
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| 4 | `CLIENT_INFO` | Planned — slave list to PC |
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| 5 | `CLIENT_INPUT` | Planned |
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| 16–20 | OTA / ESP-NOW OTA | Planned |
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Regenerate C code:
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```bash
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make proto_generate_uart
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# or:
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python libs/nanopb/generator/nanopb_generator.py main/proto/uart_messages.proto
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```
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Build embeds `POWERPOD_GIT_HASH` via `git rev-parse` in `main/CMakeLists.txt`.
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### VERSION command
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**Request:** framed payload `03` only.
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**Response:** payload `03` + nanopb `UartMessage`:
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- `type = VERSION`
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- `version_response.version` — `POWERPOD_FW_VERSION`
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- `version_response.git_hash` — build git hash string
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Encoding: `uart_send_uart_message()` in `uart_proto.c`.
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## Host tool (`goTool/`)
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Go CLI to test UART from a PC connected to the **master** only.
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```bash
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cd goTool
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go mod tidy
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go run . -port /dev/ttyUSB0
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```
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| Flag | Default | Description |
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|------|---------|-------------|
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| `-port` | (required) | Serial device, e.g. `/dev/ttyUSB0` |
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| `-baud` | `921600` | Must match `UART_BAUD_RATE` |
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Sends VERSION, reads framed response, prints `version` and `git_hash`.
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Regenerate Go protobuf:
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```bash
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protoc --go_out=./pb --go_opt=paths=source_relative \
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--go_opt=Muart_messages.proto=powerpod/gotool/pb \
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-I ../main/proto ../main/proto/uart_messages.proto
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```
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See `goTool/README.md` for tool-only notes.
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## Build and flash
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```bash
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source ~/esp/esp-idf/export.sh # or export.fish in fish
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cd /path/to/powerpod
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idf.py build
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idf.py -p /dev/ttyUSB0 flash monitor # USB-JTAG / console
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```
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Target: ESP32-S3. Close serial monitor on the UART adapter port before running `goTool` on the same device.
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## Source files
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| File | Role |
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|------|------|
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| `powerpod.c` | `app_main`, DIP/network config, init order |
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| `powerpod.h` | Pin defines |
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| `app_config.h` | `app_config_t` |
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| `esp_now_comm.c/h` | WiFi, ESP-NOW, discover / slave info |
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| `uart.c/h` | Framed UART RX/TX |
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| `uart_proto.c/h` | Encode/send `UartMessage` |
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| `cmd_handler.c/h` | Command queue and dispatch |
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| `cmd_version.c/h` | VERSION handler |
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| `led_ring.c/h` | LED digit display |
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| `proto/uart_messages.proto` | Protocol schema |
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| `proto/*.pb.c/h` | Generated nanopb |
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| `CMakeLists.txt` | Sources, `esp_wifi`, drivers, git hash |
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## Adding a new UART command
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1. Add or extend messages in `uart_messages.proto` and regenerate nanopb.
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2. Create `cmd_*.c` with a handler; register with `msg_register_handler(MessageType_…, handler)`.
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3. Reply via `uart_send_uart_message()` where needed.
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4. Extend `goTool` or another host client to send the matching frame.
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For ESP-NOW-driven PC updates later: map slave state to `ClientInfo` and send `CLIENT_INFO` over UART from the master.
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