607 lines
24 KiB
Python
607 lines
24 KiB
Python
"""
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framing.py — DLE frame codec for the Instantel MiniMate Plus RS-232 protocol.
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Wire format:
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BW→S3 (our requests): [ACK=0x41] [STX=0x02] [stuffed payload+chk] [ETX=0x03]
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S3→BW (device replies): [DLE=0x10] [STX=0x02] [stuffed payload+chk] [DLE=0x10] [ETX=0x03]
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The ACK 0x41 byte often precedes S3 frames too — it is silently discarded
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by the streaming parser.
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De-stuffed payload layout:
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BW→S3 request frame:
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[0] CMD 0x10 (BW request marker)
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[1] flags 0x00
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[2] SUB command sub-byte
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[3] 0x00 always zero in captured frames
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[4] 0x00 always zero in captured frames
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[5] OFFSET two-step offset: 0x00 = length-probe, DATA_LEN = data-request
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[6-15] zero padding (total de-stuffed payload = 16 bytes)
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S3→BW response frame:
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[0] CMD 0x00 (S3 response marker)
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[1] flags 0x10
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[2] SUB response sub-byte (= 0xFF - request SUB)
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[3] PAGE_HI high byte of page address (always 0x00 in observed frames)
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[4] PAGE_LO low byte (always 0x00 in observed frames)
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[5+] data payload data section (composite inner frames for large responses)
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DLE stuffing rule: any 0x10 byte in the payload is doubled on the wire (0x10 → 0x10 0x10).
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This applies to the checksum byte too.
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Confirmed from live captures (s3_parser.py validation + raw_bw.bin / raw_s3.bin).
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"""
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from __future__ import annotations
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from dataclasses import dataclass
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from typing import Optional
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# ── Protocol byte constants ───────────────────────────────────────────────────
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DLE = 0x10 # Data Link Escape
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STX = 0x02 # Start of text
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ETX = 0x03 # End of text
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ACK = 0x41 # Acknowledgement / frame-start marker (BW side)
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BW_CMD = 0x10 # CMD byte value in BW→S3 frames
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S3_CMD = 0x00 # CMD byte value in S3→BW frames
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S3_FLAGS = 0x10 # flags byte value in S3→BW frames
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# BW read-command payload size: 5 header bytes + 11 padding bytes = 16 total.
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# Confirmed from captured raw_bw.bin: all read-command frames carry exactly 16
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# de-stuffed bytes (excluding the appended checksum).
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_BW_PAYLOAD_SIZE = 16
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# ── DLE stuffing / de-stuffing ────────────────────────────────────────────────
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def dle_stuff(data: bytes) -> bytes:
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"""Escape literal 0x10 bytes: 0x10 → 0x10 0x10."""
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out = bytearray()
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for b in data:
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if b == DLE:
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out.append(DLE)
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out.append(b)
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return bytes(out)
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def dle_unstuff(data: bytes) -> bytes:
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"""Remove DLE stuffing: 0x10 0x10 → 0x10."""
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out = bytearray()
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i = 0
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while i < len(data):
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b = data[i]
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if b == DLE and i + 1 < len(data) and data[i + 1] == DLE:
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out.append(DLE)
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i += 2
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else:
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out.append(b)
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i += 1
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return bytes(out)
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# ── Checksum ─────────────────────────────────────────────────────────────────
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def checksum(payload: bytes) -> int:
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"""SUM8: sum of all de-stuffed payload bytes, mod 256."""
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return sum(payload) & 0xFF
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# ── BW→S3 frame builder ───────────────────────────────────────────────────────
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# SUB byte for 5A — used by build_5a_frame below (protocol.py has the full
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# constant set; defined here to avoid a circular import).
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SUB_5A = 0x5A
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def build_5a_frame(offset_word: int, raw_params: bytes) -> bytes:
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"""
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Build a BW→S3 frame for SUB 5A (BULK_WAVEFORM_STREAM) that exactly
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matches Blastware's wire output.
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SUB 5A uses a DIFFERENT frame format from all other read commands:
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1. The offset field (bytes [4:6]) is written RAW — the 0x10 in
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offset_hi=0x10 is NOT DLE-stuffed, unlike build_bw_frame().
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2. The checksum uses a DLE-aware sum: for each 0x10 XX pair in the
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stuffed section, only XX contributes; lone bytes contribute normally.
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This differs from the standard SUM8 checksum on the unstuffed payload.
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Both differences are confirmed from the 1-2-26 BW TX capture (all 10 frames
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verified against this algorithm on 2026-04-02).
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Args:
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offset_word: 16-bit offset (0x1004 for probe/chunks, 0x005A for term).
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raw_params: 10 or 11 params bytes (from bulk_waveform_params or
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bulk_waveform_term_params). 0x10 bytes in params are
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written RAW — NOT DLE-stuffed. Confirmed 2026-04-06 by
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comparing wire bytes: BW sends bare `10 04` for chunk 1
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(counter=0x1004), not stuffed `10 10 04`. Device reads
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params at fixed byte positions; stuffing shifts the bytes
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and corrupts the counter, causing device to ignore the frame.
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Returns:
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Complete frame bytes: [ACK][STX][stuffed_section][chk][ETX]
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"""
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if len(raw_params) not in (10, 11):
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raise ValueError(f"raw_params must be 10 or 11 bytes, got {len(raw_params)}")
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# Build stuffed section between STX and checksum
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s = bytearray()
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s += b"\x10\x10" # DLE-stuffed BW_CMD
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s += b"\x00" # flags
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s += bytes([SUB_5A]) # sub = 0x5A
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s += b"\x00" # field3
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s += bytes([(offset_word >> 8) & 0xFF, # offset_hi — raw, NOT stuffed
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offset_word & 0xFF]) # offset_lo
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for b in raw_params: # params — NOT DLE-stuffed (raw bytes, match BW wire format)
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s.append(b)
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# DLE-aware checksum: for 0x10 XX pairs count XX; for lone bytes count them
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chk, i = 0, 0
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while i < len(s):
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if s[i] == DLE and i + 1 < len(s):
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chk = (chk + s[i + 1]) & 0xFF
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i += 2
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else:
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chk = (chk + s[i]) & 0xFF
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i += 1
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return bytes([ACK, STX]) + bytes(s) + bytes([chk, ETX])
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def build_bw_frame(sub: int, offset: int = 0, params: bytes = bytes(10)) -> bytes:
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"""
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Build a BW→S3 read-command frame.
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The payload is always 16 de-stuffed bytes:
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[BW_CMD, 0x00, sub, 0x00, 0x00, offset] + params(10 bytes)
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Confirmed from BW capture analysis: payload[3] and payload[4] are always
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0x00 across all observed read commands. The two-step offset lives at
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payload[5]: 0x00 for the length-probe step, DATA_LEN for the data-fetch step.
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The 10 params bytes (payload[6..15]) are zero for standard reads. For
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keyed reads (SUBs 0A, 0C) the 4-byte waveform key lives at params[4..7]
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(= payload[10..13]). For token-based reads (SUBs 1E, 1F) a single token
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byte lives at params[6] (= payload[12]). Use waveform_key_params() and
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token_params() helpers to build these safely.
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Wire output: [ACK] [STX] dle_stuff(payload + checksum) [ETX]
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Args:
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sub: SUB command byte (e.g. 0x01 = FULL_CONFIG_READ)
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offset: Value placed at payload[5].
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Pass 0 for the probe step; pass DATA_LENGTHS[sub] for the data step.
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params: 10 bytes placed at payload[6..15]. Default: all zeros.
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Returns:
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Complete frame bytes ready to write to the serial port / socket.
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"""
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if len(params) != 10:
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raise ValueError(f"params must be exactly 10 bytes, got {len(params)}")
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if offset > 0xFFFF:
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raise ValueError(f"offset must fit in uint16, got {offset:#06x}")
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# offset is a uint16 split across bytes [4] (high) and [5] (low).
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# For all standard reads (offset ≤ 0xFF), byte[4] = 0x00 — consistent with
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# every captured BW frame. For large payloads (e.g. SUB 1A / E5 at 0x082A),
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# byte[4] carries the high byte. 🔶 INFERRED — confirm once E5 is captured.
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offset_hi = (offset >> 8) & 0xFF
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offset_lo = offset & 0xFF
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payload = bytes([BW_CMD, 0x00, sub, 0x00, offset_hi, offset_lo]) + params
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chk = checksum(payload)
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wire = bytes([ACK, STX]) + dle_stuff(payload + bytes([chk])) + bytes([ETX])
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return wire
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def build_bw_write_frame(
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sub: int,
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data: bytes,
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*,
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offset: int = 0,
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params: bytes = bytes(10),
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) -> bytes:
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"""
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Build a BW→S3 write-command frame.
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Write frames extend the standard 16-byte read header with a variable-length
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data payload. They use a different checksum formula from read frames.
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**CRITICAL: Write frames use minimal DLE stuffing.**
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Unlike read frames (build_bw_frame), write frames do NOT apply full DLE
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stuffing to the payload. Only the BW_CMD byte (0x10) at position [0] is
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doubled to 0x10 0x10 on the wire. All other bytes — flags, sub, offset,
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params, data, and checksum — are written RAW with no stuffing, even if they
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contain 0x10 bytes (e.g. offset_hi=0x10 for compliance chunks, or 0x10
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bytes in the write data payload).
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Confirmed from 3-11-26 BW TX capture (frames 102–112): all 11 write frames
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match the rule "double BW_CMD only; everything else raw." ✅ 2026-04-07.
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Wire layout:
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[41] ACK
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[02] STX
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[10 10] BW_CMD doubled (the ONLY DLE stuffing applied)
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[00] flags
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[sub] write command byte (0x68–0x83)
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[00] always zero
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[hi][lo] offset as uint16 BE (raw; NOT stuffed even if hi=0x10)
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[params] 10 bytes (raw)
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[data] variable-length write payload (raw; NOT stuffed)
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[chk] checksum byte (raw; NOT stuffed even if 0x10)
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[03] ETX
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De-stuffed payload (for checksum computation):
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[0] BW_CMD 0x10
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[1] flags 0x00
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[2] SUB write command byte
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[3] 0x00 always zero
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[4] offset_hi
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[5] offset_lo
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[6:16] params 10 bytes
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[16:] data write payload
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[-1] chk
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**Checksum formula (confirmed 2026-03-12 from 3-11-26 BW TX capture):**
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chk = (sum(b for b in payload[2:] if b != 0x10) + 0x10) % 256
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where payload = destuffed content BEFORE appending chk.
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This skips all 0x10 bytes in payload[2:] (sub onwards), including any
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0x10 bytes in the offset, params, data, and the checksum byte itself.
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The offset field [4:6] meaning per write SUB:
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- SUBs 68, 69, 82 (single-chunk writes): offset = data[1] + 2, where
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data[1] is an embedded length field in the write payload.
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Confirmed from capture: 68→0x5A (data[1]=0x58+2), 82→0x1C
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(data[1]=0x1A+2), 69→0xCA (data[1]=0xC8+2).
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- SUB 71 (multi-chunk compliance): 0x1004 for full chunks, 0x002C
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for the final partial chunk.
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- Confirm frames (72, 73, 74, 83): offset=0, no data.
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Args:
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sub: Write command SUB byte.
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data: Write payload (variable length; empty for confirm frames).
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offset: 16-bit value placed at [4:6]. See per-SUB notes above.
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params: 10 bytes placed at [6:16]. All-zero for most writes; compliance
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chunk writes use chunk-specific values.
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Returns:
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Complete frame bytes ready to write to the transport.
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"""
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if len(params) != 10:
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raise ValueError(f"params must be exactly 10 bytes, got {len(params)}")
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if offset > 0xFFFF:
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raise ValueError(f"offset must fit in uint16, got {offset:#06x}")
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offset_hi = (offset >> 8) & 0xFF
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offset_lo = offset & 0xFF
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# Destuffed payload (used only for checksum; not sent directly)
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payload_no_chk = bytes([BW_CMD, 0x00, sub, 0x00, offset_hi, offset_lo]) + params + data
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# Large-frame checksum: sum payload[2:] skipping all 0x10 bytes, add 0x10.
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# Applied to the destuffed representation — confirms correctly against
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# all 11 write frames in the 3-11-26/170151 BW TX capture. ✅
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chk = (sum(b for b in payload_no_chk[2:] if b != 0x10) + 0x10) & 0xFF
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# Wire construction: only BW_CMD is doubled; everything else is raw.
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# Do NOT use dle_stuff() here — that would incorrectly double 0x10 bytes
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# in the offset, params, and data sections.
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wire = (
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bytes([ACK, STX]) # Frame prefix (not part of payload)
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+ bytes([BW_CMD, BW_CMD]) # BW_CMD doubled (only DLE stuffing applied)
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+ payload_no_chk[1:] # flags, sub, offset, params, data — RAW
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+ bytes([chk]) # checksum — RAW
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+ bytes([ETX]) # Frame terminator
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)
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return wire
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def waveform_key_params(key4: bytes) -> bytes:
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"""
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Build the 10-byte params block that carries a 4-byte waveform key.
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Used for SUBs 0A (WAVEFORM_HEADER) and 0C (WAVEFORM_RECORD).
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The key goes at params[4..7], which maps to payload[10..13].
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Confirmed from 3-31-26 capture: 0A and 0C request frames carry the
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4-byte record address at payload[10..13]. Probe and data-fetch steps
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carry the same key in both frames.
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Args:
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key4: exactly 4 bytes — the opaque waveform record address returned
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by the EVENT_HEADER (1E) or EVENT_ADVANCE (1F) response.
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Returns:
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10-byte params block with key embedded at positions [4..7].
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"""
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if len(key4) != 4:
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raise ValueError(f"waveform key must be 4 bytes, got {len(key4)}")
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p = bytearray(10)
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p[4:8] = key4
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return bytes(p)
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def token_params(token: int = 0) -> bytes:
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"""
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Build the 10-byte params block that carries a single token byte.
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Used for SUBs 1E (EVENT_HEADER) and 1F (EVENT_ADVANCE).
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The token goes at params[7], which maps to payload[13].
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Confirmed from BOTH 3-31-26 and 4-3-26 BW TX captures:
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raw params bytes: 00 00 00 00 00 00 00 fe 00 00
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token is at index 7 (not 6 — that was wrong).
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- token=0x00: first-event read / browse mode (no download marking)
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- token=0xfe: download mode (causes 1F to skip partial bins and
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advance to the next full record)
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The device echoes the token at data[8] of the S3 response (payload[13]),
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distinct from the next-event key at data[11:15] (payload[16:20]).
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Args:
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token: single byte to place at params[7] / payload[13].
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Returns:
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10-byte params block with token at position [7].
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"""
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p = bytearray(10)
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p[7] = token
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return bytes(p)
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def bulk_waveform_params(key4: bytes, counter: int, *, is_probe: bool = False) -> bytes:
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"""
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Build the 10-byte params block for SUB 5A (BULK_WAVEFORM_STREAM) requests.
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Confirmed 2026-04-02 from 1-2-26 BW TX capture analysis:
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Probe / first request (is_probe=True, counter=0):
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params[0] = 0x00
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params[1:5] = key4 (all 4 key bytes; counter overlaps key4[2:4] = 0x0000)
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params[5:] = zeros
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Regular chunk requests (is_probe=False):
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params[0] = 0x00
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params[1:3] = key4[0:2] (first 2 key bytes as session handle)
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params[3:5] = counter (BE uint16) (chunk position, increments by 0x0400)
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params[5:] = zeros
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Termination request: DO NOT use this helper — see bulk_waveform_term_params().
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Args:
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key4: 4-byte waveform key from EVENT_HEADER (1E) response.
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counter: Chunk position counter (uint16 BE). Pass 0 for probe.
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is_probe: If True, embed full key4 (probe step only).
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Returns:
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11-byte params block. (BW confirmed: chunk frames carry 11 params bytes,
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not 10; the extra trailing 0x00 was confirmed from 1-2-26 wire capture
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on 2026-04-02.)
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"""
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if len(key4) != 4:
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raise ValueError(f"waveform key must be 4 bytes, got {len(key4)}")
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p = bytearray(11) # 11 bytes confirmed from BW wire capture
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p[0] = 0x00
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p[1] = key4[0]
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p[2] = key4[1]
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if is_probe:
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# Full key4; counter=0 is implied (overlaps with key4[2:4] which must be 0x0000)
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p[3] = key4[2]
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p[4] = key4[3]
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else:
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p[3] = (counter >> 8) & 0xFF
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p[4] = counter & 0xFF
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return bytes(p)
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def bulk_waveform_term_params(key4: bytes, counter: int) -> bytes:
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"""
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Build the 10-byte params block for the SUB 5A termination request.
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The termination request uses offset=0x005A and a DIFFERENT params layout —
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the leading 0x00 byte is dropped, key4[0:2] shifts to params[0:2], and the
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counter high byte is at params[2]:
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params[0] = key4[0]
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params[1] = key4[1]
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params[2] = (counter >> 8) & 0xFF
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params[3:] = zeros
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Counter for the termination request = last_regular_counter + 0x0400.
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Confirmed from 1-2-26 BW TX capture: final request (frame 83) uses
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offset=0x005A, params[0:3] = key4[0:2] + term_counter_hi.
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Args:
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key4: 4-byte waveform key.
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counter: Termination counter (= last regular counter + 0x0400).
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Returns:
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10-byte params block.
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"""
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if len(key4) != 4:
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raise ValueError(f"waveform key must be 4 bytes, got {len(key4)}")
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p = bytearray(10)
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p[0] = key4[0]
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p[1] = key4[1]
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p[2] = (counter >> 8) & 0xFF
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return bytes(p)
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# ── Pre-built POLL frames ─────────────────────────────────────────────────────
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#
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# POLL (SUB 0x5B) uses the same two-step pattern as all other reads — the
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# hardcoded length 0x30 lives at payload[5], exactly as in build_bw_frame().
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POLL_PROBE = build_bw_frame(0x5B, 0x00) # length-probe POLL (offset = 0)
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POLL_DATA = build_bw_frame(0x5B, 0x30) # data-request POLL (offset = 0x30)
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# Session-reset signal (ACK + ETX, no STX/payload).
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# Confirmed from 4-8-26 BW TX captures: Blastware sends this 2-byte sequence
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# immediately before the first POLL probe, and again between the POLL probe
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# and the POLL data request. Required to wake a unit that is actively
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# monitoring — without it the unit does not respond to POLL over TCP.
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# Harmless for idle units (they respond to POLL regardless).
|
||
SESSION_RESET = bytes([0x41, 0x03])
|
||
|
||
|
||
# ── S3 response dataclass ─────────────────────────────────────────────────────
|
||
|
||
@dataclass
|
||
class S3Frame:
|
||
"""A fully parsed and de-stuffed S3→BW response frame."""
|
||
sub: int # response SUB byte (e.g. 0xA4 = POLL_RESPONSE)
|
||
page_hi: int # PAGE_HI from header (= data length on step-2 length response)
|
||
page_lo: int # PAGE_LO from header
|
||
data: bytes # payload data section (payload[5:], checksum already stripped)
|
||
checksum_valid: bool
|
||
chk_byte: int = 0 # actual checksum byte received from wire (body[-1])
|
||
# needed for N00 file reconstruction: when the last data byte
|
||
# is 0x10 and chk_byte ∈ {0x02, 0x03, 0x04}, the DLE+chk pair
|
||
# must be included in the DLE-strip operation to correctly
|
||
# reconstruct the Blastware binary body.
|
||
|
||
@property
|
||
def page_key(self) -> int:
|
||
"""Combined 16-bit page address / length: (page_hi << 8) | page_lo."""
|
||
return (self.page_hi << 8) | self.page_lo
|
||
|
||
|
||
# ── Streaming S3 frame parser ─────────────────────────────────────────────────
|
||
|
||
class S3FrameParser:
|
||
"""
|
||
Incremental byte-stream parser for S3→BW response frames.
|
||
|
||
Feed incoming bytes with feed(). Complete, valid frames are returned
|
||
immediately and also accumulated in self.frames.
|
||
|
||
State machine:
|
||
IDLE — scanning for DLE (0x10)
|
||
SEEN_DLE — saw DLE, waiting for STX (0x02) to start a frame
|
||
IN_FRAME — collecting de-stuffed payload bytes; bare ETX ends frame
|
||
IN_FRAME_DLE — inside frame, saw DLE; DLE continues stuffing;
|
||
DLE+ETX is treated as literal data (NOT a frame end),
|
||
which lets inner-frame terminators pass through intact
|
||
|
||
Wire format confirmed from captures:
|
||
[DLE=0x10] [STX=0x02] [stuffed payload+chk] [bare ETX=0x03]
|
||
The ETX is NOT preceded by a DLE on the wire. DLE+ETX sequences that
|
||
appear inside the payload are inner-frame terminators and must be
|
||
treated as literal data.
|
||
|
||
ACK (0x41) bytes and arbitrary non-DLE bytes in IDLE state are silently
|
||
discarded (covers device boot string "Operating System" and keepalive ACKs).
|
||
"""
|
||
|
||
_IDLE = 0
|
||
_SEEN_DLE = 1
|
||
_IN_FRAME = 2
|
||
_IN_FRAME_DLE = 3
|
||
|
||
def __init__(self) -> None:
|
||
self._state = self._IDLE
|
||
self._body = bytearray() # accumulates de-stuffed frame bytes
|
||
self.frames: list[S3Frame] = []
|
||
self.bytes_fed: int = 0 # cumulative raw bytes fed since last reset
|
||
|
||
def reset(self) -> None:
|
||
self._state = self._IDLE
|
||
self._body.clear()
|
||
self.bytes_fed = 0
|
||
|
||
def feed(self, data: bytes) -> list[S3Frame]:
|
||
"""
|
||
Process a chunk of incoming bytes.
|
||
|
||
Returns a list of S3Frame objects completed during this call.
|
||
All completed frames are also appended to self.frames.
|
||
"""
|
||
self.bytes_fed += len(data)
|
||
completed: list[S3Frame] = []
|
||
for b in data:
|
||
frame = self._step(b)
|
||
if frame is not None:
|
||
completed.append(frame)
|
||
self.frames.append(frame)
|
||
return completed
|
||
|
||
def _step(self, b: int) -> Optional[S3Frame]:
|
||
"""Process one byte. Returns a completed S3Frame or None."""
|
||
|
||
if self._state == self._IDLE:
|
||
if b == DLE:
|
||
self._state = self._SEEN_DLE
|
||
# ACK, boot strings, garbage — silently ignored
|
||
|
||
elif self._state == self._SEEN_DLE:
|
||
if b == STX:
|
||
self._body.clear()
|
||
self._state = self._IN_FRAME
|
||
else:
|
||
# Stray DLE not followed by STX — back to idle
|
||
self._state = self._IDLE
|
||
|
||
elif self._state == self._IN_FRAME:
|
||
if b == DLE:
|
||
self._state = self._IN_FRAME_DLE
|
||
elif b == ETX:
|
||
# Bare ETX = real frame terminator (confirmed from captures)
|
||
frame = self._finalise()
|
||
self._state = self._IDLE
|
||
return frame
|
||
else:
|
||
self._body.append(b)
|
||
|
||
elif self._state == self._IN_FRAME_DLE:
|
||
if b == DLE:
|
||
# DLE DLE → literal 0x10 in payload
|
||
self._body.append(DLE)
|
||
self._state = self._IN_FRAME
|
||
elif b == ETX:
|
||
# DLE+ETX inside a frame is an inner-frame terminator, NOT
|
||
# the outer frame end. Treat as literal data and continue.
|
||
self._body.append(DLE)
|
||
self._body.append(ETX)
|
||
self._state = self._IN_FRAME
|
||
else:
|
||
# Unexpected DLE + byte — treat both as literal data and continue
|
||
self._body.append(DLE)
|
||
self._body.append(b)
|
||
self._state = self._IN_FRAME
|
||
|
||
return None
|
||
|
||
def _finalise(self) -> Optional[S3Frame]:
|
||
"""
|
||
Called when DLE+ETX is seen. Validates checksum and builds S3Frame.
|
||
Returns None if the frame is too short or structurally invalid.
|
||
"""
|
||
body = bytes(self._body)
|
||
|
||
# Minimum valid frame: 5-byte header + at least 1 checksum byte = 6
|
||
if len(body) < 6:
|
||
return None
|
||
|
||
raw_payload = body[:-1] # everything except the trailing checksum byte
|
||
chk_received = body[-1]
|
||
chk_computed = checksum(raw_payload)
|
||
|
||
if len(raw_payload) < 5:
|
||
return None
|
||
|
||
# Validate CMD byte — we only accept S3→BW response frames here
|
||
if raw_payload[0] != S3_CMD:
|
||
return None
|
||
|
||
return S3Frame(
|
||
sub = raw_payload[2],
|
||
page_hi = raw_payload[3],
|
||
page_lo = raw_payload[4],
|
||
data = raw_payload[5:],
|
||
checksum_valid = (chk_received == chk_computed),
|
||
chk_byte = chk_received,
|
||
)
|