KAT/docs/kia_v0.md

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Kia V0 Protocol

Rust module: src/protocols/kia_v0.rs
Reference: REFERENCES/ProtoPirate/protocols/kia_v0.c

Overview

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.

Timing

Parameter	Value	Notes
Short (0)	250 µs	±100 µs (te_delta)
Long (1)	500 µs	±100 µs
Min bits	61

Frame Layout (61 bits)

• Sync: 1 bit (the long-long pattern also counts as first data bit = 1).
• Data: 60 bits MSB first:
  • Bits 56–59: 4-bit prefix (often preserved from capture).
  • Bits 40–55: 16-bit counter.
  • Bits 12–39: 28-bit serial.
  • Bits 8–11: 4-bit button.
  • Bits 0–7: 8-bit CRC (over bits 8–55, 6 bytes).

Decoder Steps

1. Reset — Wait for short HIGH (250 µs ±100).
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.
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.
4. CheckDuration — On LOW: short–short → add bit 0, back to SaveDuration; long–long → add bit 1, back to SaveDuration; else Reset.

Encoder

• 2 bursts; inter-burst gap 25 000 µs.
• 32 alternating short (250 µs) preamble pairs.
• Sync: long HIGH, long LOW (500 µs each).
• Data: 59 bits sent (mask 1ULL << (58 - bit_num)), i.e. bits 58 down to 0 (per reference).
• End marker: long × 2 (1000 µs HIGH).

Frequencies

433.92 MHz.