Mazda V0 Protocol

Rust module: src/protocols/mazda_v0.rs Reference: REFERENCES/ProtoPirate/protocols/mazda_v0.c

Overview

Mazda V0 uses a custom pair-based encoding (not standard Manchester). The level parameter is ignored; the decoder processes raw duration pairs. Preamble: 13+ short/short pairs followed by a short+long transition into data. Data bits are collected using a prev_state tracker with inverted polarity, then XOR-deobfuscated, checksum-validated, and parsed.

Timing

Parameter	Value	Notes
Short	250 us	+/-100 us
Long	500 us	+/-100 us
Min bits	64
Completion	80-105 bits

Frame Layout (64 bits after deobfuscation)

Raw data collects into a 14-byte buffer. First byte is discarded (sync); bytes [1..9] form the 8-byte data frame.

After XOR deobfuscation:

• Bytes 0-3: Serial (32 bits)
• Byte 4: Button (8 bits)
• Bytes 5-6: Counter (16 bits)
• Byte 7: Checksum (additive sum of bytes 0-6)

Pair-Based Bit Decoding

Pair (te_last, duration)	Action
Long + Short	Collect bit(0), bit(1), prev_state=1
Short + Long	Collect bit(1), prev_state=0
Short + Short	Collect bit(prev_state)
Long + Long	Collect bit(0), bit(1), prev_state=0

Bit collection uses inverted polarity: state_bit=0 stores a 1.

XOR Deobfuscation

1. Compute parity of data[7] (XOR fold to single bit).
2. If parity is odd: XOR bytes [0..6] with data[6] as mask.
3. If parity is even: XOR bytes [0..5] with data[5] as mask, also XOR data[6] with data[5].
4. Bit interleave swap bytes 5 and 6: swap even/odd bit positions between them.

Decoder Steps

1. Reset – Wait for short pulse; save and go to PreambleCheck.
2. PreambleSave – Save duration, go to PreambleCheck.
3. PreambleCheck – Count short+short pairs; on short+long with count >= 13, start data.
4. DataSave – Save duration, go to DataCheck.
5. DataCheck – Process pair; if valid continue; if invalid, check completion (80-105 bits + checksum).

Buttons

Code	Name
0x10	Lock
0x20	Unlock
0x40	Trunk

Encoder

Not supported (decode-only).

Frequencies

433.92 MHz.