The firmware returns raw ADC envelope samples for LF reads (T55xx readbl replies
PM3_SUCCESS with NULL data); demodulation was always the C client's job, so pm3py
had none and LF identify could never see a tag. This adds the missing DSP stack in
Python — new pm3py.lf package:
- dsp.py: modulation-agnostic primitives — robust threshold, edge-interval clock
recovery, ASK binarize, half-bit resample, Manchester + biphase decode.
- protocols.py: EM4100 (ASK/Manchester -> 40-bit ID, validated by EM4100Code's own
header/row/col/stop parity checks) and best-effort T55xx block-0 config read
(find the repeating 32-bit word, score by T5577Config sanity, name the emulation).
- capture.py: live-device orchestration — read the emitted stream + probe a T55xx via
block-0 read, combine into "is it a T5577, and what is it (emulating)?".
rawcli identify now demodulates LF instead of the dead readbl-only probe: reports
"T5577 (EM4100 / EM4102)" for an emulator, "EM4100 <id>" for a bare credential.
Fully self-testing without hardware: the LF transponder models already encode these
protocols, so a synthetic envelope built from an encoder round-trips through the
demod. 17 demod tests (EM4100 across IDs/rates/mid-frame/noise, T55xx config, mocked
identify) + updated rawcli LF tests. Full suite 1225 green.
FSK/HID + PSK/Indala + biphase/FDX-B decoders queued (same dsp primitives).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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