leviathan
1.3 KiB
1.3 KiB
Scher-Khan Protocol
Rust module: src/protocols/scher_khan.rs
Reference: REFERENCES/ProtoPirate/protocols/scher_khan.c
Overview
Scher-Khan is decode-only. PWM: 750 µs = 0, 1100 µs = 1; preamble uses 2× short then alternating. Variable bit count (35, 51, 57, 63, 64, 81, 82); only 51-bit format is parsed for serial/button/counter. Reference: phreakerclub.com/72.
Timing
| Parameter | Value | Notes |
|---|---|---|
| Short (0) | 750 µs | ±160 µs |
| Long (1) | 1100 µs | ±160 µs |
| Min bits | 35 | (variable) |
Encoding
PWM; preamble: two short then alternating short/long.
Frame Layout (variable)
- 51-bit format: serial (28) | button (4) | counter (16) — “MAGIC CODE” / Dynamic; parsed for serial/btn/cnt.
- Other lengths (35, 57, 63, 64, 81, 82) decoded as raw bit count but not field-parsed.
Decoder Steps
- Reset — Wait for preamble (2 short + alternating).
- CheckPreamble — Confirm preamble pattern.
- SaveDuration — Store pulse duration.
- CheckDuration — Short–short = 0, long–long = 1 (or equivalent); add bit; on end marker, if bit_count in {35,51,57,63,64,81,82} return decode (51-bit parsed for fields).
Encoder
Not implemented (no encoder in reference).
Frequencies
433.92 MHz.