leviathan
46 lines
1.8 KiB
Markdown
46 lines
1.8 KiB
Markdown
# Kia V0 Protocol
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**Rust module:** `src/protocols/kia_v0.rs`
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**Reference:** `REFERENCES/ProtoPirate/protocols/kia_v0.c`
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## Overview
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Kia V0 is a PWM keyfob protocol: short pulse = 0, long pulse = 1. No Manchester encoding. 61 bits per frame (1 sync bit + 60 data bits). CRC8 over bits 8–55; polynomial 0x7F, init 0x00.
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## Timing
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| Parameter | Value | Notes |
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|------------|--------|--------------------|
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| Short (0) | 250 µs | ±100 µs (te_delta) |
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| Long (1) | 500 µs | ±100 µs |
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| Min bits | 61 | |
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## Frame Layout (61 bits)
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- **Sync:** 1 bit (the long-long pattern also counts as first data bit = 1).
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- **Data:** 60 bits MSB first:
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- Bits 56–59: 4-bit prefix (often preserved from capture).
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- Bits 40–55: 16-bit counter.
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- Bits 12–39: 28-bit serial.
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- Bits 8–11: 4-bit button.
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- Bits 0–7: 8-bit CRC (over bits 8–55, 6 bytes).
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## Decoder Steps
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1. **Reset** — Wait for short HIGH (250 µs ±100).
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2. **CheckPreamble** — Count preamble: alternating short pulses; on LOW, if short–short pair then `header_count++`; if long–long and `header_count > 15` → go to SaveDuration, add first bit 1.
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3. **SaveDuration** — On HIGH: if duration ≥ 500 + 200 µs (end marker), check `decode_count_bit == 61` and return decode; else store duration and go to CheckDuration. On LOW → Reset.
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4. **CheckDuration** — On LOW: short–short → add bit 0, back to SaveDuration; long–long → add bit 1, back to SaveDuration; else Reset.
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## Encoder
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- 2 bursts; inter-burst gap 25 000 µs.
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- 32 alternating short (250 µs) preamble pairs.
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- Sync: long HIGH, long LOW (500 µs each).
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- Data: 59 bits sent (mask 1ULL << (58 - bit_num)), i.e. bits 58 down to 0 (per reference).
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- End marker: long × 2 (1000 µs HIGH).
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## Frequencies
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433.92 MHz.
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