Jimmy
4fc3f46866
Replace serial/Wi-Fi driver transport paths with WebSocket bridge client, binary espnow_wire delivery, device announce registry, and restructured espnow-sender (AP + broadcast passthrough). Includes docs and tests. Co-authored-by: Cursor <cursoragent@cursor.com>
95 lines
2.5 KiB
Markdown
95 lines
2.5 KiB
Markdown
# ESP-NOW binary protocol
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**See also:** [espnow-architecture.md](espnow-architecture.md) (diagrams, flows, configuration).
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All ESP-NOW datagrams and Pi↔bridge WebSocket frames use **binary only** (no JSON on the wire). Maximum ESP-NOW payload length: **250 bytes**.
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## ESP-NOW packet
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| Offset | Field |
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|--------|--------|
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| 0 | Magic `0x4C` (`'L'`) |
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| 1 | Message type |
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| 2… | Type-specific body |
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### Message types
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| Value | Name | Direction |
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|-------|------|-----------|
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| `0x01` | `ANNOUNCE` | Driver → broadcast |
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| `0x02` | `GROUPS` | Controller → driver |
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| `0x03` | `CMD` | Controller → driver |
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| `0x04` | `GROUP_CMD` | Controller → broadcast |
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| `0x10` | `BRIDGE_CH` | Controller → broadcast |
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### ANNOUNCE (`0x01`)
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Driver settings at boot. Sender MAC is taken from the ESP-NOW peer address (not repeated in the body).
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| Field | Type |
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|-------|------|
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| name_len | u8 |
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| name | UTF-8 |
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| num_leds | u16 LE |
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| color_order | u8 enum: 0=rgb, 1=rbg, 2=grb, 3=gbr, 4=brg, 5=bgr |
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| startup_mode | u8: 0=default, 1=last, 2=off |
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| brightness | u8 0–255 |
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| device_type | u8: 0=led |
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### GROUPS (`0x02`)
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| Field | Type |
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|-------|------|
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| count | u8 |
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| × count | u8 id_len + UTF-8 group id |
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### CMD (`0x03`)
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Bytes 2… are a **v2 binary envelope** (see `src/util/binary_envelope.py`): 5-byte header + presets/select/default blobs. Total packet ≤ 250 bytes.
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### GROUP_CMD (`0x04`)
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| Field | Type |
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|-------|------|
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| group_id_len | u8 |
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| group_id | UTF-8 |
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| cmd_envelope | v2 binary envelope |
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Drivers apply the nested envelope only if `group_id` is in their stored group list.
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### BRIDGE_CH (`0x10`)
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| Field | Type |
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|-------|------|
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| channel | u8 (1–11) |
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Sets the bridge ESP32 STA channel (not forwarded to LED drivers as a command).
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## Pi ↔ bridge WebSocket frame
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Binary WebSocket messages only.
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| Offset | Field |
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|--------|--------|
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| 0 | flags: bit0 = broadcast destination; bit1 reserved |
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| 1–6 | peer MAC (6 bytes); ignored if broadcast |
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| 7… | ESP-NOW packet (magic + type + body) |
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Broadcast destination uses peer `ff:ff:ff:ff:ff:ff`.
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The bridge maintains at most **20** ESP-NOW peers (LRU eviction).
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## v2 command envelope
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Native binary sections (no JSON). Header:
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| Byte | Meaning |
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|------|---------|
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| 0 | Version `2` |
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| 1 | Brightness wire 0–127 (maps to 0–255); 128–255 = unchanged |
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| 2 | Presets section length |
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| 3 | Select section length |
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| 4 | Default section length |
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See `binary_envelope.py` for blob layouts.
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