KaraZajac
45 lines
1.5 KiB
Markdown
45 lines
1.5 KiB
Markdown
---
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layout: default
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---
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# Fiat V0 Protocol
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**Rust module:** `src/protocols/fiat_v0.rs`
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**Reference:** `REFERENCES/ProtoPirate/protocols/fiat_v0.c` (older reference)
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## Overview
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Fiat V0 uses differential Manchester. Preamble: count short pulses (HIGH or LOW, 200 µs ±100); when count ≥ 150 (0x96), accept 800 µs LOW gap and enter Data. Data: 64 bits (serial = data_low, cnt = data_high) then 7 more bits; complete when bit_count > 0x46 with btn = (data_low << 1) | 1; 71 bits total. Encoder: 150 preamble pairs, last LOW = 800 µs gap; 64 data bits then 6 button bits (btn >> 1); end marker te_short×8 LOW.
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## Timing
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| Parameter | Value | Notes |
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|------------|--------|--------------|
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| Short | 200 µs | ±100 µs |
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| Long | 400 µs | ±100 µs |
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| Preamble | ≥150 short pulses | |
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| Gap | 800 µs | ±100 µs |
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| Min bits | 71 | |
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## Encoding
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Differential Manchester; 6 button bits sent as btn >> 1; end marker 200×8 µs LOW.
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## Frame Layout (71 bits)
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- 64 bits: serial (data_low), counter (data_high).
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- 7 bits more; button = (data_low << 1) | 1 (decoded).
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## Decoder Steps
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1. **Reset** — Count short (200 µs) HIGH or LOW; when count ≥ 150 and LOW gap ~800 µs → Data.
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2. **Data** — Manchester decode; at > 0x46 bits set btn = (data_low << 1) | 1, return 71-bit decode.
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## Encoder
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Supported; 3 bursts, 25 ms inter-burst gap; 150 preamble pairs; 800 µs gap; 64 + 6 button bits; end marker.
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## Frequencies
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433.92 MHz.
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