swaitsandClaude Opus 4.6
9db901088e
- CHANGELOG.md: Full audit findings organized by severity - PYMC_CORE_ISSUES.md: 7 evidence-based bug reports for pyMC_core (wrong constants, broken path_len decoding, wrong TRACE hash, wrong SNR calculation) Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> Add comprehensive spec audit results and pyMC_core issue reports - CHANGELOG.md: Full audit findings organized by severity - PYMC_CORE_ISSUES.md: 7 evidence-based bug reports for pyMC_core (wrong constants, broken path_len decoding, wrong TRACE hash, wrong SNR calculation) - Remove ERRATA.md: contents already covered by audit findings Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
181 lines
6.3 KiB
Markdown
181 lines
6.3 KiB
Markdown
# MeshCore Protocol Specification
|
||
|
||
## Section 19: KISS Modem Protocol
|
||
|
||
### Overview
|
||
|
||
The KISS (Keep It Simple, Stupid) modem protocol provides a serial interface to
|
||
MeshCore LoRa radios. It follows the KA9Q/K3MC KISS TNC specification with
|
||
MeshCore-specific SetHardware extensions for cryptographic operations, radio
|
||
control, and telemetry.
|
||
|
||
### Serial Configuration
|
||
|
||
- Baud rate: 115200
|
||
- Data bits: 8
|
||
- Parity: None
|
||
- Stop bits: 1
|
||
- Flow control: None
|
||
|
||
### Frame Format
|
||
|
||
```
|
||
┌──────┬───────────┬──────────────┬──────┐
|
||
│ FEND │ Type Byte │ Data (escaped)│ FEND │
|
||
│ 0xC0 │ 1 byte │ 0-510 bytes │ 0xC0 │
|
||
└──────┴───────────┴──────────────┴──────┘
|
||
```
|
||
|
||
### Special Bytes
|
||
|
||
| Byte | Name | Value | Description |
|
||
|------|------|-------|-------------|
|
||
| FEND | Frame End | 0xC0 | Frame delimiter |
|
||
| FESC | Frame Escape | 0xDB | Escape character |
|
||
| TFEND | Transposed FEND | 0xDC | FESC + TFEND represents 0xC0 in data |
|
||
| TFESC | Transposed FESC | 0xDD | FESC + TFESC represents 0xDB in data |
|
||
|
||
### Byte Stuffing
|
||
|
||
To send a data byte of 0xC0 (FEND), emit: 0xDB 0xDC (FESC TFEND).
|
||
To send a data byte of 0xDB (FESC), emit: 0xDB 0xDD (FESC TFESC).
|
||
|
||
### Type Byte
|
||
|
||
```
|
||
Bit: 7 6 5 4 3 2 1 0
|
||
+---+---+---+---+---+---+---+---+
|
||
| Port (4) | Command (4) |
|
||
+---+---+---+---+---+---+---+---+
|
||
```
|
||
|
||
Port is 0 for single-port TNC (standard for MeshCore).
|
||
|
||
### Standard KISS Commands (Host to TNC)
|
||
|
||
| Command | Value | Data | Description |
|
||
|---------|-------|------|-------------|
|
||
| DataFrame | 0x00 | Raw packet | Queue packet for transmission |
|
||
| TXDELAY | 0x01 | 1 byte | Transmitter keyup delay (× 10ms) |
|
||
| Persistence | 0x02 | 1 byte | CSMA persistence (0-255) |
|
||
| SlotTime | 0x03 | 1 byte | CSMA slot interval (× 10ms) |
|
||
| TXtail | 0x04 | 1 byte | Post-TX hold time (× 10ms) |
|
||
| FullDuplex | 0x05 | 1 byte | 0=half, nonzero=full |
|
||
| SetHardware | 0x06 | Sub-cmd + data | MeshCore extensions |
|
||
| Return | 0xFF | — | Exit KISS mode (no-op) |
|
||
|
||
### TNC to Host
|
||
|
||
| Type | Value | Data | Description |
|
||
|------|-------|------|-------------|
|
||
| DataFrame | 0x00 | Raw packet | Received packet from radio |
|
||
|
||
Data frames carry raw MeshCore packets (up to 255 bytes, MAX_TRANS_UNIT).
|
||
|
||
### SetHardware Extensions (0x06)
|
||
|
||
MeshCore extends the KISS protocol via the SetHardware command. The first data
|
||
byte is a sub-command identifier.
|
||
|
||
**Request Sub-commands (Host to TNC):**
|
||
|
||
| Sub-cmd | Value | Data | Description |
|
||
|---------|-------|------|-------------|
|
||
| GetIdentity | 0x01 | — | Get node's Ed25519 public key |
|
||
| GetRandom | 0x02 | len(1) | Get random bytes (1-64) |
|
||
| VerifySignature | 0x03 | pubkey(32)+sig(64)+data | Verify Ed25519 signature |
|
||
| SignData | 0x04 | data | Ed25519 sign |
|
||
| EncryptData | 0x05 | key(32)+plaintext | AES-128 encrypt |
|
||
| DecryptData | 0x06 | key(32)+mac(2)+ciphertext | AES-128 decrypt with MAC |
|
||
| KeyExchange | 0x07 | remote_pub(32) | X25519 ECDH |
|
||
| Hash | 0x08 | data | SHA-256 hash |
|
||
| SetRadio | 0x09 | freq(4)+bw(4)+sf(1)+cr(1) | Set radio parameters |
|
||
| SetTxPower | 0x0A | power(1) | Set TX power (dBm) |
|
||
| GetRadio | 0x0B | — | Get radio parameters |
|
||
| GetTxPower | 0x0C | — | Get TX power |
|
||
| GetCurrentRssi | 0x0D | — | Get current RSSI |
|
||
| IsChannelBusy | 0x0E | — | Check if channel busy |
|
||
| GetAirtime | 0x0F | pkt_len(1) | Estimate air time |
|
||
| GetNoiseFloor | 0x10 | — | Get noise floor |
|
||
| GetVersion | 0x11 | — | Get firmware version |
|
||
| GetStats | 0x12 | — | Get RX/TX statistics |
|
||
| GetBattery | 0x13 | — | Get battery voltage |
|
||
| GetMCUTemp | 0x14 | — | Get MCU temperature |
|
||
| GetSensors | 0x15 | perms(1) | Get sensor data |
|
||
| GetDeviceName | 0x16 | — | Get device name |
|
||
| Ping | 0x17 | — | Ping |
|
||
| Reboot | 0x18 | — | Reboot device |
|
||
| SetSignalReport | 0x19 | enable(1) | Enable/disable RxMeta |
|
||
| GetSignalReport | 0x1A | — | Get signal report status |
|
||
|
||
**Response Sub-commands (TNC to Host):**
|
||
|
||
Response codes: `response = command | 0x80`
|
||
|
||
| Sub-cmd | Value | Data |
|
||
|---------|-------|------|
|
||
| Identity | 0x81 | pubkey(32) |
|
||
| Random | 0x82 | random_bytes(1-64) |
|
||
| Verify | 0x83 | result(1): 0=invalid, 1=valid |
|
||
| Signature | 0x84 | signature(64) |
|
||
| Encrypted | 0x85 | mac(2)+ciphertext |
|
||
| Decrypted | 0x86 | plaintext |
|
||
| SharedSecret | 0x87 | secret(32) |
|
||
| HashResult | 0x88 | hash(32) |
|
||
| Radio | 0x8B | freq(4)+bw(4)+sf(1)+cr(1) |
|
||
| TxPower | 0x8C | power(1) |
|
||
| CurrentRssi | 0x8D | rssi(1, signed) |
|
||
| ChannelBusy | 0x8E | busy(1): 0=clear, 1=busy |
|
||
| Airtime | 0x8F | millis(4) |
|
||
| NoiseFloor | 0x90 | dBm(2, signed) |
|
||
| Version | 0x91 | version(1)+reserved(1) |
|
||
| Stats | 0x92 | rx(4)+tx(4)+errors(4) |
|
||
| Battery | 0x93 | millivolts(2) |
|
||
| MCUTemp | 0x94 | temp(2, signed, tenths °C) |
|
||
| Sensors | 0x95 | CayenneLPP data |
|
||
| DeviceName | 0x96 | name(UTF-8) |
|
||
| Pong | 0x97 | — |
|
||
| SignalReport | 0x9A | status(1) |
|
||
| OK | 0xF0 | — |
|
||
| Error | 0xF1 | error_code(1) |
|
||
| TxDone | 0xF8 | result(1): 0=fail, 1=success |
|
||
| RxMeta | 0xF9 | snr(1)+rssi(1) |
|
||
|
||
### Error Codes
|
||
|
||
| Code | Value | Description |
|
||
|------|-------|-------------|
|
||
| InvalidLength | 0x01 | Request data too short |
|
||
| InvalidParam | 0x02 | Invalid parameter value |
|
||
| NoCallback | 0x03 | Feature not available |
|
||
| MacFailed | 0x04 | MAC verification failed |
|
||
| UnknownCmd | 0x05 | Unknown sub-command |
|
||
| EncryptFailed | 0x06 | Encryption failed |
|
||
|
||
### Unsolicited Events
|
||
|
||
**TxDone (0xF8)**: Sent after packet transmission. 0x01 = success, 0x00 = fail.
|
||
|
||
**RxMeta (0xF9)**: Sent after each received data frame. Contains:
|
||
- SNR: 1 byte, signed, × 4 for 0.25 dB precision
|
||
- RSSI: 1 byte, signed, dBm
|
||
|
||
### Data Format Notes
|
||
|
||
- Maximum payload per frame: 255 bytes (MAX_TRANS_UNIT)
|
||
- Frames larger than 255 unescaped bytes are silently dropped
|
||
- All multi-byte integers are little-endian
|
||
- Radio frequency is in Hz (e.g., 869618000)
|
||
- Battery voltage in millivolts
|
||
- MCU temperature in tenths of °C (e.g., 253 = 25.3°C)
|
||
|
||
### Cross-References
|
||
|
||
- [Section 1: Wire Format](01-wire-format.md) — Packet format within data frames
|
||
- [Section 14: Cryptography](14-crypto.md) — Crypto operations via SetHardware
|
||
- Test vectors: `corpus/kiss/`
|
||
|
||
### Reference Implementation
|
||
|
||
- `docs/kiss_modem_protocol.md` in the MeshCore repository
|