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merge: the Series-4 event chain, a 64 KB cap closed, and a cost model corrected

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Step 4 of docs/micromate_client_spec.md plus what measuring it turned up.
Read-only throughout; still nothing in this project has ever originated a
command against a unit.

The event chain: MicromateEventRef, list_events(), iter_events(),
download_event(), get_event() and decode_error().  The load-bearing test replays
THOR's captured six-event session and asserts every byte we emit matches its 74
frames, while decoding all six events and cross-checking each waveform's peak
vector sum against the float the device computed itself.

Three things hardware found that captures could not:

1. A 64 KB DOWNLOAD CAP, one event away from biting.  The 0x5A chunk offset was
   a uint16 because every offset THOR sends fits in two bytes; UM20147 holds a
   72,560-byte event.  params[0:4] is one 4-byte field (chunk 0 puts the key
   there), so a uint32 is byte-identical below 65,536 and reaches past it.
   Confirmed on the unit: 71 chunks, exact size.  This is the Series III 64 KB
   page-boundary bug wearing a different hat, and that one is still open.

2. NO 0x5A STREAMING MODE -- retracted.  The offset field is simply a byte count
   and the device returns offset + 11 bytes in one frame.  But the probe that
   killed the hypothesis showed 1024 B is THOR's choice, not the device's limit:
   the ceiling is 16,384, and above it the device CLAMPS SILENTLY with correct
   bytes and no error.  That is why the download loop now tracks its offset by
   bytes received rather than striding by chunk index.

3. CELLULAR COST IS NOT INDEPENDENT OF PAYLOAD.  I had it as ~0.65 s per round
   trip regardless of size and built design advice on it.  Measured against a
   14,176 B response: t ~ 0.21 s + bytes/2,350.  The old figure was right for a
   1 KB response and was a narrow-range fit extrapolated past its evidence --
   every sample behind it was under 1 KB.  Status work is round-trip bound;
   downloads are throughput bound, so 16 KB chunks save ~30%, not 14x.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ru8Lg9HkkYvX9VWWo65SmL
This commit is contained in:
serversdown
2026-10-02 19:27:15 -04:00
co-authored by Claude Opus 5
parent e95d8e3b8c 338ce4fea7
commit 4a11eadc91
8 changed files with 1406 additions and 68 deletions
Download Patch File Download Diff File Expand all files Collapse all files
bridges/mm_client_check.py
+89 -21
View File
@@ -232,6 +232,18 @@ def _decode(blob: bytes, key: bytes, record: bytes) -> None:
print(f" saved to {out} for offline analysis") print(f" saved to {out} for offline analysis")
def _select(refs, which: str):
"""Pick which events `--download` fetches."""
which = which.strip().lower()
if which == "first":
return refs[:1]
if which == "all":
return refs
if which == "largest":
return [max(refs, key=lambda r: r.size)]
return [r for r in refs if r.key_hex.lower() == which]
def step(label: str, fn): def step(label: str, fn):
"""Run one read, report how long it took and what it returned.""" """Run one read, report how long it took and what it returned."""
t0 = time.monotonic() t0 = time.monotonic()
@@ -259,7 +271,12 @@ def main() -> int:
"and negotiates its own rate.") "and negotiates its own rate.")
ap.add_argument("--timeout", type=float, default=10.0) ap.add_argument("--timeout", type=float, default=10.0)
ap.add_argument("--download", action="store_true", ap.add_argument("--download", action="store_true",
help="also download the first stored event (read-only)") help="also walk the event chain and download (read-only)")
ap.add_argument("--event", default="first", metavar="WHICH",
help="which event --download fetches: a key in hex "
"(e.g. 055d4a83), 'first', 'largest', or 'all'. "
"'largest' is the one worth running on an unfamiliar "
"unit -- it is what exercises offsets past 64 KB.")
ap.add_argument("--capture", metavar="DIR", ap.add_argument("--capture", metavar="DIR",
help="also write a raw_bw_*/raw_s3_*.bin pair to DIR, so " help="also write a raw_bw_*/raw_s3_*.bin pair to DIR, so "
"this run can become a test fixture. Worth doing on " "this run can become a test fixture. Worth doing on "
@@ -291,6 +308,12 @@ def main() -> int:
try: try:
info = step("connect() identity", mm.connect) info = step("connect() identity", mm.connect)
if info is None:
print("\n Nothing answered. If the port opened but no frame came back,")
print(" check it is actually a Micromate and not another CDC-ACM device —")
print(" /dev/ttyACM* numbering shifts when anything else is plugged in.")
print(" `ls -l /dev/serial/by-id/` names each device and is stable.")
return 3
if info: if info:
print(f" serial={info.serial} model={info.model} " print(f" serial={info.serial} model={info.model} "
f"fw={info.firmware_line} monitoring={info.monitoring}") f"fw={info.firmware_line} monitoring={info.monitoring}")
@@ -314,25 +337,67 @@ def main() -> int:
if setups: if setups:
print(f" first={setups[0]!r} last={setups[-1]!r}") print(f" first={setups[0]!r} last={setups[-1]!r}")
# ── SUB 0x06: is content[0:4] really the event count? ─────────────
# Two samples on one unit said yes, and THOR reads it BEFORE the chain
# walk then stops without ever reading the sentinel. A third value
# either confirms it or kills it.
claimed = None
raw06 = step("0x06 storage range", mm.protocol.read_storage_range)
if raw06:
c = _content(raw06)
claimed = int.from_bytes(c[0:4], "big")
print(f" content[0:4] = {claimed} <- CANDIDATE: event count")
print(f" content[4:8] = {int.from_bytes(c[4:8],'big')} "
f"<- unexplained (read 9 alongside a 6 on UM12947)")
if a.download: if a.download:
print("\n event chain (read-only):") print("\n event chain (read-only), via MicromateClient:")
proto = mm.protocol t1 = time.monotonic()
proto.arm_event() refs = mm.list_events() # walks to the sentinel
hdr = _content(proto.read_event_first()) walk = time.monotonic() - t1
key, size = hdr[0:4], int.from_bytes(hdr[4:8], "big") print(f" {len(refs)} events in {walk:.1f} s "
if not size: f"({walk/max(len(refs),1):.2f} s each, 3 round trips per event)")
print(" no events stored")
else: if claimed is not None:
rec = _content(proto.read_event_record(key)) verdict = ("✓ AGREES" if claimed == len(refs)
print(f" first event key={key.hex()} size={size} B " else f"✗ DISAGREES (0x06 said {claimed})")
f"type={_event_type(rec)}") print(f" 0x06 count vs chain length: {verdict}")
t1 = time.monotonic()
blob = proto.read_event_file(key, size) for ref in refs:
dt = time.monotonic() - t1 print(f" {ref}")
print(f" downloaded {len(blob)} B in {dt:.1f} s " print(f" would be filed as {ref.filename}")
f"({len(blob)/dt/1024:.1f} KiB/s)")
assert len(blob) == size if refs:
_decode(blob, key, rec) wanted = _select(refs, a.event)
if not wanted:
print(f"\n --event {a.event!r} matched nothing")
else:
print(f"\n download ({len(wanted)} of {len(refs)}, "
f"THOR's interleaved order):")
want_keys = {r.key_hex for r in wanted}
# iter_events() walks the chain; download only the selected
# events, at the cursor position THOR would be at.
for ref in mm.iter_events():
if ref.key_hex not in want_keys:
continue
n_chunks = -(-ref.size // 1024)
note = (" <- past 64 KB, carries into params[1]"
if ref.size > 0x10000 else "")
t1 = time.monotonic()
try:
result = mm.get_event(ref) # verify=True
except Exception as e:
print(f" {ref.key_hex} {ref.size:7} B "
f"FAILED {type(e).__name__}: {e}")
continue
dt = max(time.monotonic() - t1, 1e-6)
n = sum(len(v) for v in getattr(result, "samples", {}).values())
err = mm.decode_error(ref, result)
check = ("PVS %+.4f%%" % (100 * err) if err is not None
else "PVS n/a (histogram)")
print(f" {ref.key_hex} {ref.record_type:9} "
f"{ref.size:7} B {n_chunks:3} chunks {dt:5.1f} s "
f"{n:6} samples {check}{note}")
except ProtocolError as e: except ProtocolError as e:
print(f"\n ABORTED {type(e).__name__}: {e}") print(f"\n ABORTED {type(e).__name__}: {e}")
@@ -354,8 +419,11 @@ def main() -> int:
print(" RX55 (TCP) 36 reads list_setups 16.05 s download 1.6 KiB/s") print(" RX55 (TCP) 36 reads list_setups 16.05 s download 1.6 KiB/s")
print(" The modem needs FEWER reads, not more -- it buffers ~1 s and then") print(" The modem needs FEWER reads, not more -- it buffers ~1 s and then")
print(" forwards one large segment, where CDC-ACM delivers many small ones.") print(" forwards one large segment, where CDC-ACM delivers many small ones.")
print(" Cost is ~0.65 s PER ROUND TRIP regardless of payload size, so what") print(" Cellular cost, measured: ~0.21 s per request + ~2,350 B/s.")
print(" matters over cellular is the number of commands, not the bytes.\n") print(" So STATUS work is round-trip bound (minimise commands) but a")
print(" DOWNLOAD is throughput bound -- 16 KB chunks save ~30% on a large")
print(" event, not 14x. An earlier note claiming cost was independent of")
print(" payload was fitted only to sub-1 KB responses.\n")
return 0 return 0
docs/micromate_protocol_reference.md
+156 -12
View File
@@ -694,19 +694,94 @@ key size(1E) chunks sum(offsets) last offset
055d4a86 6092 6 6092 0x03cc 055d4a86 6092 6 6092 0x03cc
``` ```
**These are probably two different modes, not a contradiction.** THOR's > #### ⚠ RETRACTED 2026-10-02 — there is no streaming mode
`offset_hi` is the chunk length (`0x04`, `0x03`, `0x00` …). Our single-request >
probes set `offset_hi = 0x10` — which in Series III is precisely the > This section previously hypothesised that `offset_hi = 0x10` meant "stream
bulk-stream marker `build_5a_frame()` writes raw. So `0x10XX` plausibly means > until done" and returned several frames, reconciling THOR's chunk loop with
"stream until done" and returns **several** frames, which the parser of the day > our 2026-09-23 single-request observation. **Measured directly on UM20147,
concatenated into the 11,049 bytes recorded below. That reconciles both > it does not:**
observations, but it is a hypothesis: those 2026-09-23 captures never landed in >
the repo, so it cannot be re-derived from bytes on disk. > | request | one frame returns | file bytes |
> |---|---|---|
> | `offset = 0x1014` (4,116) | 4,127 B data | **4,116** |
> | `offset = 0x111c` (4,380) | 4,391 B data | **4,380** |
>
> **`offset` is simply a byte count.** The device returns exactly `offset + 11`
> bytes in one frame, and `page_key` is `offset // 256`. `0x1000` is not a
> marker — it is part of the number. One model covers every `0x5A` request ever
> observed, THOR's and ours.
>
> So the 2026-09-23 note that `offset_word = 0x1000 + 2 × pages` returned an
> entire 11 KB event is **wrong**: `0x102C` is 4,140, and 4,140 bytes is what it
> would have returned. Most likely the 11,049 figure was the whole capture
> rather than one frame's payload. Those captures never landed in the repo, so
> the error cannot be traced further — but it does not need to be, because the
> live measurement is unambiguous.
>
> 🔑 **And the negative result turned up something better. See below.**
### 🔑 1024 bytes per request is THOR's choice, not the device's limit
The retraction above has a payoff. In establishing that `offset` is a plain byte
count, UM20147 served **4,380 bytes in a single frame** without being asked
twice. THOR uses 1024; nothing about the device requires it.
That matters because of the round-trip cost: ~0.65 s each over cellular,
regardless of payload. A 72,560-byte event is **71 requests ≈ 46 seconds** at
THOR's chunk size. The offset field is a **uint16**, so the structural ceiling is
**65,535 bytes per request** — which would make that same event **2 requests,
~1.3 seconds**.
#### ✅ Confirmed over a cellular modem too (2026-10-02)
UM12947 on an RX55, every size checked byte-for-byte against a 1024 B control:
**1,024 / 2,048 / 4,096 / 8,192 / 14,176 all served in one frame, intact.** Its
largest event is 14,176 B, so the 16,384 ceiling itself was not reached — but a
14 KB single response crossing the PAD unscathed is the thing that needed
proving. The reader reads to frame completion rather than using idle-gap
detection, which is why ~10 TCP segments reassemble without special handling.
#### ✅ The ceiling is 16,384 bytes, and over it the device CLAMPS SILENTLY
Measured on UM20147, each size checked byte-for-byte against a known-good
download:
| requested | served | |
|---|---|---|
| 1,024 | 1,024 | ✅ |
| 2,048 | 2,048 | ✅ |
| 4,096 | 4,096 | ✅ |
| 8,192 | 8,192 | ✅ |
| **16,384** | **16,384** | ✅ |
| 32,768 | **16,384** | ⚠ clamped |
| 65,535 | **16,384** | ⚠ clamped |
⚠ **The clamp is silent and the bytes are correct.** A 32,768-byte request
returns 16,384 bytes of perfectly good data and no error. There is nothing in the
response to say it was truncated — the length is the only signal.
**That is what dictates how the download loop must be written.** A loop striding
by a fixed chunk size would either fail on a clamp or, worse, skip the bytes it
never collected. `read_event_file()` therefore tracks its offset by **bytes
received**, which makes a clamp cost one extra request rather than corrupting the
file — and makes the loop self-correcting against any short response, which is
precisely the failure mode that has bitten the Series III side repeatedly.
`CHUNK_SIZE` is now **16,384**. For UM20147's events:
| event | THOR's 1024 | 16,384 | cellular |
|---|---|---|---|
| 4,796 B | 5 requests | **1** | ~3.3 s → ~0.7 s |
| 30,230 B | 30 | **2** | ~20 s → ~1.3 s |
| 72,560 B | 71 | **5** | ~46 s → ~3.2 s |
⚠ **Measured on one unit, over USB.** `THOR_CHUNK_SIZE = 1024` remains available
and the replay tests pin it, so reproducing THOR's exact traffic is still one
argument away. A unit that clamps lower than 16,384 costs extra requests, not a
failure.
**Implement THOR's chunked form.** It is verified byte-exact across six events **Implement THOR's chunked form.** It is verified byte-exact across six events
and five distinct sizes, and it is what the firmware runs every day. The and five distinct sizes, and it is what the firmware runs every day.
single-request form is worth one bench test as an optimisation — `offset_hi =
0x10` and count the frames — but not worth depending on first.
### The offset word is a LENGTH, not a position ### The offset word is a LENGTH, not a position
@@ -811,7 +886,37 @@ across reads, and the modem splits **less** than USB does. The client reads to
frame completion rather than using `read_until_idle`'s idle-gap detection, and frame completion rather than using `read_until_idle`'s idle-gap detection, and
handled both without a retry. handled both without a retry.
### 🔑 ~0.65 s per round trip over cellular, independent of payload ### 🔑 The cellular cost model — ~0.21 s per request + ~2,350 B/s
> #### ⚠ CORRECTED 2026-10-02 — it is NOT independent of payload
>
> This section previously read **"~0.65 s per round trip, independent of payload
> size"**, and concluded *"minimise round trips, not bytes"*. The first claim is
> wrong and the second is too strong.
>
> Every measurement behind it had a **small** payload — 59 B status, 266 B setup
> records, 1024 B download chunks. With the byte term small and similar across
> all of them, per-command cost looked constant. It was a narrow-range fit
> extrapolated past its evidence.
>
> Measured against a 14,176 B single response on UM12947 over an RX55:
>
> | request | measured | model |
> |---|---|---|
> | 1,024 B | 0.67 s | 0.65 s |
> | 2,048 B | 1.22 s | 1.08 s |
> | 4,096 B | 2.13 s | 1.96 s |
> | 8,192 B | 3.59 s | 3.70 s |
> | 14,176 B | 6.25 s | 6.25 s |
>
> **`t ≈ 0.21 s + bytes / 2,350`** — fits within ±11% across a 14× size range.
>
> The old 0.65 s figure was *right for a 1024-byte response* and is simply that
> model evaluated at 1 KB. Round trips still cost real money (0.21 s each, and
> 24 of them for a setup walk is still 16 s), but **bytes cost more than round
> trips on anything over ~500 B**, and that reverses the design advice: for
> *status* work minimise commands; for *downloads* the floor is throughput and no
> amount of batching beats it.
This is the number that matters for SFM's design. This is the number that matters for SFM's design.
@@ -994,6 +1099,45 @@ its counter resets, so keys are reused *within* a unit, which is why
`ach_state.json` tracks `max_downloaded_key` per serial. Series IV inherits that `ach_state.json` tracks `max_downloaded_key` per serial. Series IV inherits that
and adds cross-unit collision on top. and adds cross-unit collision on top.
### ⚠ 🔑 The chunk offset is a uint32 — and a 64 KB cap was one event away
UM20147 holds a **72,560-byte** event (`055d4a83`). The `0x5A` chunk offset was
implemented as a **uint16 at `params[2:4]`**, because every offset THOR was
observed to send fits in two bytes — the largest is `0x3400` (13,312). That caps
a download at **65,536 bytes**, so that event could not have been fetched at all.
`params[0:4]` is demonstrably **one 4-byte field**: chunk 0 puts the 4-byte event
key there. Writing the offset as a uint32 BE in the same slot is **byte-identical
for every offset below 65,536** — so it changes nothing that was verified against
THOR's 74 captured frames — and extends the range to 4 GB.
✅ **Confirmed on hardware 2026-10-01.** UM20147's 72,560-byte event
(`055d4a83`) downloaded in **71 chunks** at exactly its promised size — chunks
64–70 carry a `0x01` in `params[1]`, and the device served them without
complaint. The field is a uint32; it was inference for one commit.
🔑 **And it prices a large event over cellular.** 71 chunks × ~0.65 s ≈ **46
seconds** for one 72 KB histogram, against 0.2 s over USB. That is the
round-trip cost model doing real work: the bytes are nothing, the commands are
everything. A unit holding several events this size is a multi-minute call, and
the untested single-request `offset_hi = 0x10` streaming mode would collapse it
to one round trip — which moves that two-minute bench test up the list.
⚠ **At offset 1 MiB `params[1]` is `0x10`**, which must be escaped on the wire as
`10 10`. Unreachable below 64 KB, so the uint32 change is what first makes that
case possible — and an unescaped `0x10` in `5A` params is the exact bug that cost
the Series III walk a release.
**This is the Series III 64 KB page-boundary bug wearing a different hat.** There,
`parse_strt_end_offset()` discards the key's page byte and the walk crashes once a
unit's buffer crosses 64 KB; that is **still open**. The transferable lesson:
*an address field whose high bytes are zero in every capture is not a narrow
field, it is an untested one.* Both bugs are the same mistake, found twice, in
code written years apart.
**The test is sitting on a desk:** download `055d4a83` from UM20147 and see
whether 71 chunks come back.
### Still not covered ### Still not covered
- **A unit that is monitoring**, and a unit with a nearly-full event buffer. - **A unit that is monitoring**, and a unit with a nearly-full event buffer.
- **The inbound call-home session** — still the one protocol unknown. - **The inbound call-home session** — still the one protocol unknown.
micromate/client.py
+281 -1
View File
@@ -32,11 +32,14 @@ from __future__ import annotations
import datetime import datetime
import logging import logging
import math
import os
import struct
from typing import Optional from typing import Optional
from minimateplus.transport import BaseTransport from minimateplus.transport import BaseTransport
from .models import MicromateDeviceInfo, MicromateState from .models import MicromateDeviceInfo, MicromateEventRef, MicromateState
from .protocol import MicromateProtocol, ProtocolError from .protocol import MicromateProtocol, ProtocolError
log = logging.getLogger(__name__) log = logging.getLogger(__name__)
@@ -57,6 +60,27 @@ _MS_BATTERY = slice(34, 36) # uint16 BE, volts × 100
_MS_MEM_TOTAL = slice(36, 40) # uint32 BE _MS_MEM_TOTAL = slice(36, 40) # uint32 BE
_MS_MEM_FREE = slice(40, 44) # uint32 BE _MS_MEM_FREE = slice(40, 44) # uint32 BE
# `SUB 0x0C` record, relative to content. Established against 7 events across
# both firmware lines.
_REC_DAY, _REC_MONTH, _REC_YEAR = 0, 1, slice(2, 4)
_REC_UNKNOWN_4 = 4 # ⚠ same shape as 0x1C's content[6]; undecoded
_REC_HOUR, _REC_MIN, _REC_SEC = 5, 6, 7
_REC_TYPE = 11 # 0x07 waveform, 0x08 histogram
_REC_LOCATION = 12
_REC_SETUP = 34
_REC_SERIAL = 76
_RECORD_TYPES = {0x07: "waveform", 0x08: "histogram"}
# The channel labels the record carries, in the order they appear. The peak
# float sits `label + 6`; the peak vector sum sits 12 bytes BEFORE "Tran".
_REC_CHANNELS = (b"Tran", b"Vert", b"Long", b"Mic")
_REC_PVS_BACK = 12
# A chain walk terminates on an all-zero key. The ceilings below are guards
# against a device cursor that never advances, not fleet limits.
_NULL_KEY = bytes(4)
_MAX_EVENTS = 4096
# A setup-list walk that does not terminate is a bug, not a big fleet. The # A setup-list walk that does not terminate is a bug, not a big fleet. The
# bench unit holds 22 setups; this is a generous ceiling, not a limit. # bench unit holds 22 setups; this is a generous ceiling, not a limit.
_MAX_SETUPS = 512 _MAX_SETUPS = 512
@@ -71,6 +95,10 @@ def _cstring(buf: bytes, offset: int = 0) -> str:
return buf[offset:].split(b"\x00")[0].decode("ascii", "replace").strip() return buf[offset:].split(b"\x00")[0].decode("ascii", "replace").strip()
class DecodeMismatch(ProtocolError):
"""Our decoded peak disagrees with the one the device computed itself."""
class MicromateClient: class MicromateClient:
"""High-level read-only client for one Micromate. """High-level read-only client for one Micromate.
@@ -88,6 +116,7 @@ class MicromateClient:
transport, recv_timeout=recv_timeout, strict_checksums=strict_checksums transport, recv_timeout=recv_timeout, strict_checksums=strict_checksums
) )
self._firmware_line: Optional[str] = None self._firmware_line: Optional[str] = None
self._serial: Optional[str] = None
# ── Lifecycle ───────────────────────────────────────────────────────────── # ── Lifecycle ─────────────────────────────────────────────────────────────
@@ -140,6 +169,7 @@ class MicromateClient:
manufacturer, model = self._parse_poll(poll.data) manufacturer, model = self._parse_poll(poll.data)
serial = _cstring(_content(self._proto.read_serial())) serial = _cstring(_content(self._proto.read_serial()))
self._serial = serial
monitoring = self._parse_state(self._proto.read_state()) monitoring = self._parse_state(self._proto.read_state())
info = MicromateDeviceInfo( info = MicromateDeviceInfo(
@@ -293,3 +323,253 @@ class MicromateClient:
f"setup list did not terminate after {_MAX_SETUPS} entries — the " f"setup list did not terminate after {_MAX_SETUPS} entries — the "
f"device cursor is not advancing" f"device cursor is not advancing"
) )
# ── Events ────────────────────────────────────────────────────────────────
def serial(self) -> str:
"""The unit's serial, cached from `connect()` or read on demand.
Needed by anything that handles an event, because an event key is
ambiguous without it — see `MicromateEventRef`.
"""
if self._serial is None:
self._serial = _cstring(_content(self._proto.read_serial()))
return self._serial
def list_events(self, *, with_records: bool = True) -> list[MicromateEventRef]:
"""Walk the event chain. `0x93 → 1E`, then `0x93 → 1F` until the sentinel.
THOR sends `0x93` before **every** chain read, and this mirrors that.
The chain ends on an all-zero key.
⚠ `with_records=True` costs **one extra round trip per event** for the
`0x0C` read, and over cellular a round trip is ~0.65 s regardless of
size. On a unit with 40 events that is the difference between ~52 s and
~78 s. Pass False when you only need "what is here and how big" — but
note the **record is where the type and timestamp live**, so without it
`ref.filename` is None and `get_event()` cannot pick a suffix.
⚠ **To download, prefer `iter_events()`.** This walks the whole chain
first; THOR interleaves, downloading each event before advancing.
`0x5A` addresses an event by key, so downloading afterwards *should*
work — but "should" is doing real work in that sentence, and the
interleaved order is the one with captures behind it. See
`iter_events()`.
"""
serial = self.serial()
refs: list[MicromateEventRef] = []
for i in range(_MAX_EVENTS):
self._proto.arm_event()
raw = (self._proto.read_event_first() if i == 0
else self._proto.read_event_next())
c = _content(raw)
if len(c) < 8:
raise ProtocolError(
f"chain entry {i}: {len(c)} B of content, need 8 (key + size)"
)
key, size = c[0:4], int.from_bytes(c[4:8], "big")
if key == _NULL_KEY:
return refs # the sentinel, not an error
ref = MicromateEventRef(index=i, key=key, size=size, serial=serial)
if with_records:
self._read_record_into(ref)
refs.append(ref)
raise ProtocolError(
f"event chain did not terminate after {_MAX_EVENTS} entries — the "
f"device cursor is not advancing"
)
def iter_events(self, *, with_records: bool = True):
"""Walk the chain, yielding each event **at the cursor position THOR uses.**
for ref in mm.iter_events():
if ref.is_histogram:
continue
data = mm.download_event(ref) # ← safe here
Why this exists alongside `list_events()`: THOR's captured order is
0x93 → 1E → 0C → 5A×n → 0x93 → 1F → 0C → 5A×n → …
— it downloads each event *before* advancing the chain. `list_events()`
walks to the end first, which is fine for browsing (the browse walk is
separately attested) but means a later download happens with the device
cursor parked past the event. `0x5A` is key-addressed, so it very
probably does not care; nothing observed says it does, and nothing
observed says it does not.
Downloading inside this loop reproduces THOR's sequence exactly, so it
is the path to use when it matters. ⚠ Do not advance the generator
before finishing with the event it yielded.
"""
serial = self.serial()
for i in range(_MAX_EVENTS):
self._proto.arm_event()
raw = (self._proto.read_event_first() if i == 0
else self._proto.read_event_next())
c = _content(raw)
if len(c) < 8:
raise ProtocolError(
f"chain entry {i}: {len(c)} B of content, need 8 (key + size)"
)
key, size = c[0:4], int.from_bytes(c[4:8], "big")
if key == _NULL_KEY:
return
ref = MicromateEventRef(index=i, key=key, size=size, serial=serial)
if with_records:
self._read_record_into(ref)
yield ref
raise ProtocolError(
f"event chain did not terminate after {_MAX_EVENTS} entries — the "
f"device cursor is not advancing"
)
def _read_record_into(self, ref: MicromateEventRef) -> None:
"""`SUB 0x0C` — 210 B of content: timestamp, type, names, peaks."""
raw = self._proto.read_event_record(ref.key)
c = _content(raw)
if len(c) <= _REC_SERIAL:
raise ProtocolError(f"event record is {len(c)} B, too short to decode")
ref.raw_record = raw
ref.record_type = _RECORD_TYPES.get(c[_REC_TYPE])
if ref.record_type is None:
# Worth saying out loud rather than filing the event as a waveform:
# the suffix decides which codec runs.
log.warning("event %s: unknown record type 0x%02x at content[%d]",
ref.key_hex, c[_REC_TYPE], _REC_TYPE)
try:
ref.timestamp = datetime.datetime(
year=int.from_bytes(c[_REC_YEAR], "big"),
month=c[_REC_MONTH], day=c[_REC_DAY],
hour=c[_REC_HOUR], minute=c[_REC_MIN], second=c[_REC_SEC],
)
except ValueError as e:
log.warning("event %s: bad timestamp (%s): %s",
ref.key_hex, e, c[:8].hex(" "))
ref.sensor_location = _cstring(c, _REC_LOCATION) or None
ref.setup = _cstring(c, _REC_SETUP) or None
# Prefer the record's own serial over the cached one — they have always
# agreed, but the record is the event's own account of where it came from.
if rec_serial := _cstring(c, _REC_SERIAL):
ref.serial = rec_serial
peaks: dict[str, float] = {}
for label in _REC_CHANNELS:
i = c.find(label)
if i < 0 or i + len(label) + 10 > len(c):
continue
peaks[label.decode()] = struct.unpack(
">f", c[i + len(label) + 2: i + len(label) + 6])[0]
ref.peaks_ips = peaks or None
tran = c.find(b"Tran")
if tran >= _REC_PVS_BACK:
ref.peak_vector_sum_ips = struct.unpack(
">f", c[tran - _REC_PVS_BACK: tran - _REC_PVS_BACK + 4])[0]
def download_event(self, ref: MicromateEventRef, *,
chunk_size: Optional[int] = None) -> bytes:
"""The raw `.IDFW`/`.IDFH` bytes, exactly as THOR would have stored them.
Feeds `micromate.idf_file.read_idf_file()` and `/db/import/idf_file`
unchanged — no new codec work is needed for a directly downloaded event.
`chunk_size` defaults to the measured device ceiling (16,384 B), which is
16x THOR's 1024 and therefore ~14x fewer round trips on a large event.
Pass `THOR_CHUNK_SIZE` to reproduce THOR's wire traffic exactly, or a
smaller value on a link where big responses are not surviving.
"""
kw = {} if chunk_size is None else {"chunk_size": chunk_size}
return self._proto.read_event_file(ref.key, ref.size, **kw)
def get_event(self, ref: MicromateEventRef, *, verify: bool = True,
tolerance: float = 0.01, chunk_size: Optional[int] = None):
"""Download and decode one event.
Returns the codec's `IdfReadResult`. Needs `ref.record_type`, since
`read_idf_file()` dispatches on the filename suffix and there is no
filename on the wire — so call `list_events(with_records=True)` first.
⚠ `verify=True` re-computes the **peak vector sum** from the decoded
samples and compares it against the float the *device* put in the `0x0C`
record. Those are two independent computations over the same samples —
the device's from its own firmware, ours from our codec — so a
disagreement means our decode is wrong. Measured agreement on the bench
events is **0.000%**.
This is cheap insurance in a codebase whose decode failures have
historically been *silent*: unhandled block tags shorten a channel and
nothing raises. ⚠ It is a decode-correctness check, **not** a
truncation detector — a channel cut after its peak still yields the
right PVS.
Histograms are not verified: `samples` is empty for them.
"""
if not ref.record_type:
raise ValueError(
f"event {ref.key_hex}: record_type is unknown, so the codec "
f"cannot be dispatched. Use list_events(with_records=True)."
)
blob = self.download_event(ref, chunk_size=chunk_size)
import tempfile
from .idf_file import read_idf_file
# read_idf_file dispatches on the suffix, so the bytes need a name.
with tempfile.NamedTemporaryFile(suffix=ref.suffix, delete=False) as f:
f.write(blob)
tmp = f.name
try:
result = read_idf_file(tmp)
finally:
os.unlink(tmp)
if verify and not ref.is_histogram:
err = self.decode_error(ref, result)
if err is not None and abs(err) > tolerance:
raise DecodeMismatch(
f"event {ref.uid}: decoded peak vector sum differs from the "
f"device's own by {100 * err:+.3f}% (tolerance "
f"{100 * tolerance:.1f}%) — the decode is suspect, not the "
f"device. Stored {ref.peak_vector_sum_ips:.5f} in/s."
)
if err is not None:
log.debug("event %s: PVS agrees to %+.4f%%", ref.uid, 100 * err)
return result
@staticmethod
def decode_error(ref: MicromateEventRef, result) -> Optional[float]:
"""Relative error between our decoded PVS and the device's stored one.
None when either side is unavailable. Positive means the device's
figure is higher than ours.
"""
from .idf_file import geo_count_to_ips
stored = ref.peak_vector_sum_ips
if not stored or not getattr(result, "samples", None):
return None
ch = {k.lower(): v for k, v in result.samples.items()}
try:
t, v, l = ch["tran"], ch["vert"], ch["long"]
except KeyError:
return None
n = min(len(t), len(v), len(l))
if not n:
return None
pvs = max(
math.sqrt(geo_count_to_ips(t[i]) ** 2
+ geo_count_to_ips(v[i]) ** 2
+ geo_count_to_ips(l[i]) ** 2)
for i in range(n)
)
return (stored - pvs) / pvs if pvs else None
micromate/models.py
+73
View File
@@ -478,3 +478,76 @@ class MicromateState:
if frac is not None: if frac is not None:
bits.append(f"memory {frac * 100:.1f}% used") bits.append(f"memory {frac * 100:.1f}% used")
return " ".join(bits) return " ".join(bits)
@dataclass
class MicromateEventRef:
"""One entry in a unit's event chain, from `1E`/`1F` and optionally `0x0C`.
⚠ **`key` is NOT unique across units.** The event counter starts from the
same value on every Micromate — UM12947 and UM20147 both have an event
`055d4a81`, with different sizes and different contents. Use `uid`, or key
on `(serial, key_hex)`, for anything that stores or deduplicates. A store
keyed on the event key alone silently treats one unit's event as a duplicate
of another's, and nothing raises.
"""
index: int
key: bytes # 4-byte event key from the chain walk
size: int # bytes the device will send for this event
serial: Optional[str] = None # the unit, because `key` alone is ambiguous
# From `SUB 0x0C` — one extra round trip per event, so optional.
record_type: Optional[str] = None # "waveform" | "histogram"
timestamp: Optional[datetime.datetime] = None
setup: Optional[str] = None # setup file name, no extension
sensor_location: Optional[str] = None
peak_vector_sum_ips: Optional[float] = None # per-sample PVS, device-computed
peaks_ips: Optional[Dict[str, float]] = None # {"Tran": …, "Vert": …, …}
raw_record: Optional[bytes] = field(default=None, repr=False)
@property
def key_hex(self) -> str:
return self.key.hex()
@property
def uid(self) -> str:
"""`SERIAL:key` — safe to use as a primary key. See the class note."""
return f"{self.serial or '?'}:{self.key_hex}"
@property
def is_histogram(self) -> Optional[bool]:
if self.record_type is None:
return None
return self.record_type == "histogram"
@property
def suffix(self) -> Optional[str]:
return {"waveform": ".IDFW", "histogram": ".IDFH"}.get(self.record_type or "")
@property
def filename(self) -> Optional[str]:
"""The name THOR would have given this event.
`<serial>_<YYYYMMDDHHMMSS>.IDF{W,H}` — e.g.
`UM12947_20260923163319.IDFW`. Verified against the production store
for all five bench events.
⚠ The type comes from the **protocol**, not the payload, so it has to be
carried here from the `0x0C` read. Returns None without it: guessing
the suffix would file a histogram as a waveform, and `read_idf_file()`
dispatches on exactly that.
"""
if not (self.serial and self.timestamp and self.suffix):
return None
return f"{self.serial}_{self.timestamp:%Y%m%d%H%M%S}{self.suffix}"
def __str__(self) -> str:
bits = [self.uid, f"{self.size} B"]
if self.record_type:
bits.append(self.record_type)
if self.timestamp:
bits.append(self.timestamp.strftime("%Y-%m-%d %H:%M:%S"))
if self.peak_vector_sum_ips is not None:
bits.append(f"PVS {self.peak_vector_sum_ips:.4f} in/s")
return " ".join(bits)
micromate/protocol.py
+86 -22
View File
@@ -106,8 +106,30 @@ OBSERVED_DATA_LEN = {
# bulk stream; here THOR sends it on every chain read, browse or download. # bulk stream; here THOR sends it on every chain read, browse or download.
EVENT_TOKEN = 0xFE EVENT_TOKEN = 0xFE
# `SUB 0x5A` chunk size, in bytes of file payload per response. # `SUB 0x5A` request size, in bytes of file payload per response.
CHUNK_SIZE = 1024 #
# ⚠ **16,384, not THOR's 1024.** Measured on UM20147 (2026-10-02): requests of
# 1024 / 2048 / 4096 / 8192 / 16384 all returned byte-identical data against a
# known-good download, and anything larger is **silently clamped to 16,384** —
# correct bytes, short length, no error.
#
# ⚠ The win is real but MODEST, and smaller than a first reading suggests.
# Measured over an RX55, cost per request is ~0.21 s + bytes/2350 — so a download
# is throughput-bound, not round-trip bound. A 72,560-byte event costs ~46 s at
# THOR's 1024 B and ~32 s at 16,384 B: a **30% saving**, not 14x, because ~31 s of
# it is bytes on the wire and no amount of batching addresses that.
#
# Still worth having: 30% faster, and 14x fewer requests is 14x fewer chances for
# a link to drop mid-download.
#
# ⚠ Measured on ONE unit, over USB. The loop below is driven by bytes received
# rather than chunk index, so a unit that clamps lower simply takes more
# requests instead of failing — which is what makes raising this safe.
CHUNK_SIZE = 16384
# THOR's value. Pass `chunk_size=THOR_CHUNK_SIZE` to reproduce its wire traffic
# exactly; the replay test does.
THOR_CHUNK_SIZE = 1024
# Every `0x5A` response prefixes the file bytes with 11 bytes of header. # Every `0x5A` response prefixes the file bytes with 11 bytes of header.
_CHUNK_PREFIX = 11 _CHUNK_PREFIX = 11
@@ -170,15 +192,38 @@ def chunk_params(key4: bytes, byte_offset: int) -> bytes:
"""`0x5A`: the key opens the file, then a byte offset walks it. """`0x5A`: the key opens the file, then a byte offset walks it.
Chunk 0 carries the event key at params[0:4] — that is what says "from the Chunk 0 carries the event key at params[0:4] — that is what says "from the
beginning". Later chunks carry a uint16 BE byte offset at params[2:4]. beginning". Later chunks carry the byte offset **in that same 4-byte slot**,
as a uint32 BE.
⚠ **Written as a uint32 deliberately, and this matters above 64 KB.** Every
offset THOR was observed to send fits in two bytes — the largest was `0x3400`
(13,312) — so `params[0:2]` was always `00 00` and the field looks like a
uint16 at `params[2:4]`. Reading it that way caps a download at **65,536
bytes**, and UM20147 currently holds a **72,560-byte** event, so that cap is
not hypothetical.
A uint32 here is **byte-identical for every offset below 65,536**, so it
changes nothing that was verified against THOR's frames (the replay test
asserts all 74 of them) and extends the range to 4 GB.
✅ **Confirmed on hardware 2026-10-01.** UM20147's 72,560-byte event
downloaded in **71 chunks** at the exact promised size, which exercises the
carry into `params[1]` on chunks 64–70. It was inference for one commit and
is now evidence.
⚠ This is the **Series III 64 KB page-boundary bug in a new guise** — there,
`parse_strt_end_offset()` discards the key's page byte and the `5A` walk
crashes once a unit's buffer crosses 64 KB, which is *still open* on that
side. The lesson that transfers: an address field whose high bytes are zero
in every capture is not a narrow field, it is an untested one.
""" """
if byte_offset == 0: if byte_offset == 0:
if len(key4) != 4: if len(key4) != 4:
raise ValueError(f"key4 must be 4 bytes, got {len(key4)}") raise ValueError(f"key4 must be 4 bytes, got {len(key4)}")
return key4 + bytes(6) return key4 + bytes(6)
if not 0 <= byte_offset <= 0xFFFF: if not 0 <= byte_offset <= 0xFFFFFFFF:
raise ValueError(f"byte_offset must fit in uint16, got {byte_offset}") raise ValueError(f"byte_offset must fit in uint32, got {byte_offset}")
return bytes(2) + struct.pack(">H", byte_offset) + bytes(6) return struct.pack(">I", byte_offset) + bytes(6)
# ── Protocol ────────────────────────────────────────────────────────────────── # ── Protocol ──────────────────────────────────────────────────────────────────
@@ -350,14 +395,15 @@ class MicromateProtocol:
# ── Bulk download ───────────────────────────────────────────────────────── # ── Bulk download ─────────────────────────────────────────────────────────
def read_event_file(self, key4: bytes, size: int) -> bytes: def read_event_file(self, key4: bytes, size: int, *,
chunk_size: int = CHUNK_SIZE) -> bytes:
"""`0x5A` → `0xA5`. The `.IDFW`/`.IDFH` file, byte for byte. """`0x5A` → `0xA5`. The `.IDFW`/`.IDFH` file, byte for byte.
`size` is the 4 bytes after the key in the `1E`/`1F` response. Returns `size` is the 4 bytes after the key in the `1E`/`1F` response. Returns
exactly that many bytes, or raises `ShortRead`. exactly that many bytes, or raises `ShortRead`.
A bounded chunk walk — `ceil(size / 1024)` requests, each asking for A bounded walk — `ceil(size / chunk_size)` requests, each asking for
`min(1024, remaining)` bytes: `min(chunk_size, remaining)` bytes:
offset = the byte count wanted (NOT an address) offset = the byte count wanted (NOT an address)
params = the key on chunk 0, then a uint16 BE byte offset params = the key on chunk 0, then a uint16 BE byte offset
@@ -378,36 +424,54 @@ class MicromateProtocol:
if size <= 0: if size <= 0:
raise ValueError(f"size must be positive, got {size}") raise ValueError(f"size must be positive, got {size}")
if chunk_size < 1:
raise ValueError(f"chunk_size must be positive, got {chunk_size}")
# ⚠ Driven by BYTES RECEIVED, not by chunk index.
#
# The device silently clamps an over-large request: ask for 32,768 and it
# returns exactly 16,384 — correct bytes, short length, no error. A loop
# that strides by a fixed chunk size would either fail on that or, worse,
# skip the bytes it never collected. Tracking the offset by what actually
# arrived makes the clamp a non-event: it just takes another request.
#
# That also makes this self-correcting against any short response, which
# is the failure mode this codebase has been bitten by repeatedly on the
# Series III side — there, a short read surfaced as a silently truncated
# channel.
out = bytearray() out = bytearray()
n_chunks = math.ceil(size / CHUNK_SIZE) requests = 0
for i in range(n_chunks): while len(out) < size:
want = min(CHUNK_SIZE, size - i * CHUNK_SIZE) want = min(chunk_size, size - len(out))
data = self._read( data = self._read(
SUB_BULK_DOWNLOAD, SUB_BULK_DOWNLOAD,
offset=want, offset=want,
params=chunk_params(key4, i * CHUNK_SIZE), params=chunk_params(key4, len(out)),
) )
requests += 1
if len(data) < _CHUNK_PREFIX: if len(data) < _CHUNK_PREFIX:
raise ShortRead( raise ShortRead(
f"chunk {i + 1}/{n_chunks} of {key4.hex()}: " f"{key4.hex()} at offset {len(out)}: {len(data)} B is too "
f"{len(data)} B is too short to hold a chunk header" f"short to hold a chunk header"
) )
body = data[_CHUNK_PREFIX:] body = data[_CHUNK_PREFIX:]
if len(body) != want: if not body:
# Worth being loud: a silently short event is the failure mode # No progress at all — continuing would spin forever.
# this project has been bitten by repeatedly on the Series III
# side, and here the expected length is known up front.
raise ShortRead( raise ShortRead(
f"chunk {i + 1}/{n_chunks} of {key4.hex()}: asked for " f"{key4.hex()} at offset {len(out)}: asked for {want} B and "
f"{want} B, got {len(body)}" f"got none; {len(out)} of {size} B assembled"
) )
if len(body) < want:
log.debug("%s: asked %d B at offset %d, served %d — clamped",
key4.hex(), want, len(out), len(body))
out += body out += body
if len(out) != size: if len(out) != size:
raise ShortRead( raise ShortRead(
f"{key4.hex()}: assembled {len(out)} B, device promised {size}" f"{key4.hex()}: assembled {len(out)} B, device promised {size}"
) )
log.debug("downloaded %s: %d B in %d chunks", key4.hex(), len(out), n_chunks) log.debug("downloaded %s: %d B in %d request(s)",
key4.hex(), len(out), requests)
return bytes(out) return bytes(out)
# ── Plumbing ────────────────────────────────────────────────────────────── # ── Plumbing ──────────────────────────────────────────────────────────────
scratch/mm_stream_probe.py
+228
View File
@@ -0,0 +1,228 @@
#!/usr/bin/env python3
"""
mm_stream_probe.py — how many bytes will `SUB 0x5A` serve in one request?
Settled 2026-10-02: there is NO streaming mode
----------------------------------------------
This script started out asking whether `offset_hi = 0x10` meant "stream until
done", because our 2026-09-23 notes recorded a single request appearing to return
an entire 11 KB event. Measured directly on UM20147, it does not:
offset 0x1014 (4116) -> one frame, 4127 B data, 4116 B of file
offset 0x111c (4380) -> one frame, 4391 B data, 4380 B of file
**`offset` is simply a byte count**, and the device returns exactly `offset + 11`
bytes in one frame. `0x1000` is not a marker; it is part of the number. The
2026-09-23 reading was wrong, and the protocol reference now says so.
The useful question it turned up
-------------------------------
**1024 bytes per request is THOR's choice, not the device's limit.** The unit
served 4,380 bytes in a single frame without being asked twice. Since a round
trip over cellular costs ~0.65 s regardless of payload, and UM20147's
72,560-byte event is 71 chunks ≈ 46 seconds, the ceiling on one request is worth
knowing precisely: every doubling halves the dominant cost.
So this now walks ascending request sizes against one event and **checks each
against a known-good chunk-loop download** — a pass means byte-identical output,
not merely a plausible length. The offset field is a uint16, so 65,535 is the
structural maximum.
⚠ **Read-only.** `0x5A` is a read we have sent thousands of times; the only new
thing is a larger value in its offset field. Nothing here writes, erases or
changes monitoring state. It re-POLLs at the end, because the honest risk is
leaving the session in an odd state and the script should say so.
Usage
-----
python3 scratch/mm_stream_probe.py /dev/ttyACM1
python3 scratch/mm_stream_probe.py /dev/ttyACM1 --event largest
"""
from __future__ import annotations
import argparse
import math
import sys
import time
from pathlib import Path
sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
sys.path.insert(0, str(Path(__file__).resolve().parent.parent / "bridges"))
from micromate.client import MicromateClient, _content # noqa: E402
from micromate.framing import MicromateFrameParser, build_request # noqa: E402
from micromate.protocol import SUB_BULK_DOWNLOAD, THOR_CHUNK_SIZE # noqa: E402
from mm_client_check import StdlibSerial # noqa: E402
from minimateplus.transport import TcpTransport # noqa: E402
_CHUNK_PREFIX = 11
def collect(transport, parser, *, idle_gap: float, deadline: float) -> list:
"""Read until `idle_gap` seconds pass with no new bytes, or `deadline`."""
frames, last = [], time.monotonic()
while time.monotonic() < deadline:
chunk = transport.read(4096)
if chunk:
frames += parser.feed(chunk)
last = time.monotonic()
continue
if time.monotonic() - last > idle_gap:
break
time.sleep(0.005)
return frames
def main() -> int:
ap = argparse.ArgumentParser(
description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter
)
ap.add_argument("target", help="host:port, or a serial device path")
ap.add_argument("--baud", type=int, default=115200)
ap.add_argument("--event", default="smallest",
help="a key in hex, 'smallest' (default — the gentlest "
"first test) or 'largest' (the one that matters)")
ap.add_argument("--idle-gap", type=float, default=3.0,
help="seconds of silence that end a read. A 16 KB response "
"is ~1.4 s of serial time at 115200 BEFORE the modem's "
"~1 s forwarding delay, so this is deliberately roomy; "
"too small and a slow link looks like a clamp.")
ap.add_argument("--timeout", type=float, default=90.0)
a = ap.parse_args()
if ":" in a.target and not Path(a.target).exists():
host, _, port = a.target.rpartition(":")
inner = TcpTransport(host, int(port), connect_timeout=10.0)
label = f"TCP {host}:{port}"
else:
inner = StdlibSerial(a.target, baud=a.baud)
label = f"serial {a.target} @ {a.baud}"
mm = MicromateClient(inner, recv_timeout=20.0)
print(f"\n{label} READ-ONLY: chain walk + two downloads of one event\n")
mm.open()
try:
info = mm.connect(with_active_setup=False)
print(f" {info}\n")
refs = mm.list_events()
if not refs:
print(" no events stored — nothing to download. Record one first.")
return 1
for r in refs:
print(f" {r}")
which = a.event.strip().lower()
if which == "smallest":
ref = min(refs, key=lambda r: r.size)
elif which == "largest":
ref = max(refs, key=lambda r: r.size)
else:
matches = [r for r in refs if r.key_hex.lower() == which]
if not matches:
print(f"\n --event {a.event!r} matched nothing")
return 2
ref = matches[0]
n_chunks = math.ceil(ref.size / THOR_CHUNK_SIZE)
print(f"\n target: {ref.key_hex} {ref.size} B {ref.record_type} "
f"({n_chunks} requests at THOR's chunk size)")
# ── 1. the control: THOR's 1024-byte chunk loop ───────────────────────
# ⚠ Pinned to THOR_CHUNK_SIZE on purpose. The library default is now
# 16,384, and using it here would make the experiment circular -- the
# "known-good" reference would share any fault with the sizes under test.
# 1024 is the size with THOR's own captures behind it and the one proven
# over a modem, so it is the control.
t0 = time.monotonic()
chunked = mm.protocol.read_event_file(ref.key, ref.size,
chunk_size=THOR_CHUNK_SIZE)
dt_chunked = time.monotonic() - t0
print(f"\n [1] control ......... {len(chunked)} B in {dt_chunked:.2f} s "
f"({n_chunks} requests at THOR's 1024 B)")
# ── 2. how many bytes will it serve in ONE frame? ─────────────────
# The streaming hypothesis is dead (see the module docstring): `offset`
# is simply a BYTE COUNT, and the device returns `offset + 11` bytes in
# one frame. So the real question is the ceiling -- because 1024 is
# THOR's choice, not the device's limit, and every doubling halves the
# round trips that dominate a cellular download.
print("\n [2] chunk-size ceiling — ascending single requests")
print(" each asks for N bytes from offset 0 and is checked against")
print(" the known-good download, so a pass means identical bytes.\n")
candidates = [1024, 2048, 4096, 8192, 16384, 32768, 65535]
candidates = [n for n in candidates if n <= ref.size] or [ref.size]
if ref.size not in candidates and ref.size < 65536:
candidates.append(ref.size) # the whole event in one request
best = None
for n in candidates:
frame = build_request(SUB_BULK_DOWNLOAD, n, ref.key + bytes(6))
parser = MicromateFrameParser()
t0 = time.monotonic()
mm.protocol._send(frame)
got = collect(inner, parser, idle_gap=a.idle_gap,
deadline=t0 + a.timeout)
dt = time.monotonic() - t0
if not got:
print(f" {n:6} B no answer ({dt:.2f} s)")
continue
body = b"".join(f.data[_CHUNK_PREFIX:] for f in got)
ok = body == chunked[:n]
flag = "OK " if ok else "MISMATCH"
# ⚠ dt includes the idle gap: collect() waits `idle_gap` after the
# last byte before deciding the response is over. Subtract it to
# compare against the control, which reads to frame completion.
print(f" {n:6} B {len(got)} frame(s) {len(body):6} B back "
f"{dt:5.2f} s ({max(dt - a.idle_gap, 0):4.2f} s net) {flag}"
+ ("" if ok or not body else
f" (first diff at {next((i for i in range(min(len(body), n)) if body[i] != chunked[i]), None)})"))
if ok and len(body) == n:
best = n
print()
if best is None:
print(" VERDICT: nothing above the current chunk size verified.")
else:
now = math.ceil(ref.size / THOR_CHUNK_SIZE)
then = math.ceil(ref.size / best)
print(f" VERDICT: the device serves at least {best} B per request,")
print(f" verified byte-identical. For this {ref.size} B event that")
print(f" is {then} request(s) instead of {now}.")
if best > THOR_CHUNK_SIZE:
# ⚠ cost is ~0.21 s per request PLUS ~2,350 B/s over a modem --
# a download is throughput-bound, so do not promise a saving
# proportional to the drop in request count.
fixed, rate = 0.212, 2348.0
t_now = now * fixed + ref.size / rate
t_then = then * fixed + ref.size / rate
print(f" Modelled over cellular (0.21 s/request + "
f"{rate:.0f} B/s): {t_now:.1f} s -> {t_then:.1f} s, "
f"a {100 * (1 - t_then / t_now):.0f}% saving.")
print(" Throughput-bound, not round-trip bound — most of that is")
print(" bytes on the wire and batching does not touch it.")
if best >= ref.size:
print(" The WHOLE EVENT fits in one request.")
# ── 3. is the unit still healthy? ─────────────────────────────────────
# The real risk of this experiment is leaving the session wedged, so
# check rather than assume.
print()
try:
p = mm.protocol.poll()
print(f" [3] unit still answering POLL (SUB 0x{p.sub:02x}) — "
f"session is healthy")
except Exception as e:
print(f" [3] ⚠ POLL FAILED after the probe: {type(e).__name__}: {e}")
print(" Reconnect; if that does not help, power-cycle the unit.")
return 4
finally:
mm.close()
return 0
if __name__ == "__main__":
raise SystemExit(main())
tests/test_micromate_events.py
+345
View File
@@ -0,0 +1,345 @@
"""Event-chain tests for the Micromate (series-4) client.
The load-bearing test here replays THOR's captured six-event download session
through `MicromateClient.iter_events()` + `get_event()` and asserts **every byte
we put on the wire matches what THOR put on the wire** — 99 frames — while also
decoding all six events and cross-checking each waveform's peak vector sum
against the one the device computed itself.
That capture is gitignored, so those tests skip on a fresh clone; the offline
tests below use embedded real response bytes and cover the same logic.
"""
from __future__ import annotations
import datetime
import os
import sys
from pathlib import Path
import pytest
sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
from micromate.client import CONTENT, DecodeMismatch, MicromateClient
from micromate.framing import ACK, DLE, ETX, STX, checksum, stuff
from micromate.models import MicromateEventRef
from micromate.protocol import ProtocolError
from test_micromate_client import ScriptedTransport, SERIAL, frame
# The real 0x0C record from UM20147 (11.0BD), captured over USB 2026-09-30.
# A histogram: content[11] = 0x08.
RECORD_BD = bytes.fromhex(
"d200000000055d4a8100001e0907eab30d1b21000000084c6f636174696f6e00"
"0000000000000000000000000074657374320000000000000000000000000000"
"0000000000000000000000000000000000000000000000554d32303134370000"
"003fcb3bde00000000053f000f5472616e00003e698cdb000300005665727400"
"003fc76e65000300004c6f6e6700003e567c21000300004d69630000003956b9"
"7c00050000000000000000000000000000000000000000000000000000000000"
"0000000000000000000000000000000000000000000000000000000000"
)
def chain_entry(key: bytes, size: int) -> bytes:
"""A 1E/1F response data section: 11-byte prefix then key + size."""
return (bytes([0x08]) + bytes(7) + bytes([0xFE]) + bytes(2)
+ key + size.to_bytes(4, "big"))
def client(responses):
t = ScriptedTransport(responses)
return MicromateClient(t, recv_timeout=0.5), t
# ── The chain walk ────────────────────────────────────────────────────────────
def test_chain_walk_arms_before_every_entry():
"""⚠ THOR sends 0x93 before EVERY 1E/1F, and this mirrors that."""
responses = [
frame(0xEA, SERIAL), # serial()
frame(0x6C, bytes(11)), frame(0xE1, chain_entry(bytes.fromhex("055d4a81"), 4076)),
frame(0x6C, bytes(11)), frame(0xE0, chain_entry(bytes.fromhex("055d4a82"), 11032)),
frame(0x6C, bytes(11)), frame(0xE0, chain_entry(bytes(4), 0)), # sentinel
]
mm, t = client(responses)
refs = mm.list_events(with_records=False)
subs = [w[5] for w in t.written]
assert subs == [0x15, 0x93, 0x1E, 0x93, 0x1F, 0x93, 0x1F]
assert [r.key_hex for r in refs] == ["055d4a81", "055d4a82"]
assert [r.size for r in refs] == [4076, 11032]
def test_an_all_zero_key_ends_the_chain_and_is_not_an_error():
mm, _ = client([
frame(0xEA, SERIAL),
frame(0x6C, bytes(11)), frame(0xE1, chain_entry(bytes(4), 0)),
])
assert mm.list_events(with_records=False) == []
def test_refs_carry_the_serial_because_a_key_alone_is_ambiguous():
"""⚠ UM12947 and UM20147 BOTH have an event 055d4a81.
A store keyed on the event key alone treats one unit's event as a duplicate
of the other's, and nothing raises. `uid` is the safe identifier.
"""
mm, _ = client([
frame(0xEA, SERIAL),
frame(0x6C, bytes(11)), frame(0xE1, chain_entry(bytes.fromhex("055d4a81"), 4076)),
frame(0x6C, bytes(11)), frame(0xE0, chain_entry(bytes(4), 0)),
])
(ref,) = mm.list_events(with_records=False)
assert ref.serial == "UM12947"
assert ref.uid == "UM12947:055d4a81"
def test_a_cursor_that_never_advances_raises_rather_than_hanging():
from micromate import client as C
responses = [frame(0xEA, SERIAL)]
entry = chain_entry(bytes.fromhex("055d4a81"), 4076)
responses += [frame(0x6C, bytes(11)), frame(0xE1, entry)] # the 1E read
for _ in range(C._MAX_EVENTS + 2): # then 1F forever
responses += [frame(0x6C, bytes(11)), frame(0xE0, entry)]
mm, _ = client(responses)
with pytest.raises(ProtocolError, match="not advancing"):
mm.list_events(with_records=False)
def test_a_truncated_chain_entry_raises():
mm, _ = client([
frame(0xEA, SERIAL), frame(0x6C, bytes(11)), frame(0xE1, bytes(14)),
])
with pytest.raises(ProtocolError, match="need 8"):
mm.list_events(with_records=False)
def test_iter_events_does_not_read_ahead():
"""It must yield at the cursor position, one arm/advance per event."""
mm, t = client([
frame(0xEA, SERIAL),
frame(0x6C, bytes(11)), frame(0xE1, chain_entry(bytes.fromhex("055d4a81"), 4076)),
frame(0x6C, bytes(11)), frame(0xE0, chain_entry(bytes(4), 0)),
])
it = mm.iter_events(with_records=False)
first = next(it)
assert [w[5] for w in t.written] == [0x15, 0x93, 0x1E], "no read-ahead"
assert first.key_hex == "055d4a81"
assert list(it) == []
# ── The 0x0C record ───────────────────────────────────────────────────────────
def test_record_decode_on_real_bd_bytes():
mm, _ = client([
frame(0xEA, SERIAL),
frame(0x6C, bytes(11)), frame(0xE1, chain_entry(bytes.fromhex("055d4a81"), 4796)),
frame(0xF3, RECORD_BD),
frame(0x6C, bytes(11)), frame(0xE0, chain_entry(bytes(4), 0)),
])
(ref,) = mm.list_events()
assert ref.record_type == "histogram" # content[11] = 0x08
assert ref.is_histogram is True
assert ref.suffix == ".IDFH"
assert ref.timestamp == datetime.datetime(2026, 9, 30, 13, 27, 33)
assert ref.sensor_location == "Location"
assert ref.setup == "test2"
assert ref.serial == "UM20147", "the record's own serial wins over the cache"
assert ref.peak_vector_sum_ips == pytest.approx(1.587765, abs=1e-5)
assert ref.peaks_ips["Tran"] == pytest.approx(0.228076, abs=1e-5)
assert ref.peaks_ips["Vert"] == pytest.approx(1.558056, abs=1e-5)
assert ref.peaks_ips["Long"] == pytest.approx(0.209458, abs=1e-5)
def test_the_pvs_is_not_reconstructible_from_the_reported_peaks():
"""⚠ Why the PVS field matters: it cannot be recomputed from the peaks.
It is the PER-SAMPLE peak vector sum. `sqrt(Σpeak²)` is only an upper
bound, because the channel maxima do not occur at the same instant, and
`max(T,V,L)` is a lower bound. On THIS event the two happen to be within
0.05%, which is exactly the coincidence that made the field look like
`sqrt(Σpeak²)` on first inspection. Six other events separated them.
"""
import math
mm, _ = client([
frame(0xEA, SERIAL),
frame(0x6C, bytes(11)), frame(0xE1, chain_entry(bytes.fromhex("055d4a81"), 4796)),
frame(0xF3, RECORD_BD),
frame(0x6C, bytes(11)), frame(0xE0, chain_entry(bytes(4), 0)),
])
(ref,) = mm.list_events()
p = ref.peaks_ips
upper = math.sqrt(p["Tran"] ** 2 + p["Vert"] ** 2 + p["Long"] ** 2)
lower = max(p["Tran"], p["Vert"], p["Long"])
assert lower < ref.peak_vector_sum_ips < upper
def test_filename_matches_thors_convention():
ref = MicromateEventRef(index=0, key=bytes.fromhex("055d4a82"), size=11032,
serial="UM12947", record_type="waveform",
timestamp=datetime.datetime(2026, 9, 23, 16, 33, 19))
assert ref.filename == "UM12947_20260923163319.IDFW"
ref.record_type = "histogram"
assert ref.filename == "UM12947_20260923163319.IDFH"
def test_filename_is_none_without_a_type_rather_than_guessing():
"""⚠ Guessing would file a histogram as a waveform, and read_idf_file()
dispatches on exactly that suffix."""
ref = MicromateEventRef(index=0, key=bytes(4), size=1, serial="UM12947",
timestamp=datetime.datetime(2026, 1, 1))
assert ref.record_type is None
assert ref.suffix is None
assert ref.filename is None
def test_an_unknown_record_type_warns_and_leaves_it_none(caplog):
bad = bytearray(RECORD_BD)
bad[CONTENT + 11] = 0x99
mm, _ = client([
frame(0xEA, SERIAL),
frame(0x6C, bytes(11)), frame(0xE1, chain_entry(bytes.fromhex("055d4a81"), 10)),
frame(0xF3, bytes(bad)),
frame(0x6C, bytes(11)), frame(0xE0, chain_entry(bytes(4), 0)),
])
with caplog.at_level("WARNING"):
(ref,) = mm.list_events()
assert ref.record_type is None
assert "unknown record type 0x99" in caplog.text
def test_get_event_refuses_without_a_record_type():
mm, _ = client([])
ref = MicromateEventRef(index=0, key=bytes.fromhex("055d4a81"), size=4076)
with pytest.raises(ValueError, match="record_type is unknown"):
mm.get_event(ref)
# ── Against the real captured session ─────────────────────────────────────────
_CAPTURES = (
Path(__file__).resolve().parents[1]
/ "bridges" / "captures" / "9-24-26 - micromate2"
)
_DOWNLOAD = "raw_bw_20260925_011403_Download_events_then_delete_1_event.bin"
def _destuffed(blob: bytes, is_req: bool):
i, n = 0, len(blob)
while i < n:
if is_req:
if not (blob[i] == ACK and i + 1 < n and blob[i + 1] == STX):
i += 1
continue
j = i + 2
else:
if blob[i] != STX:
i += 1
continue
j = i + 1
out = bytearray()
while j < n:
if blob[j] == DLE and j + 1 < n:
out.append(blob[j + 1])
j += 2
continue
if blob[j] == ETX:
break
out.append(blob[j])
j += 1
if len(out) >= 6:
yield blob[i:j + 1], bytes(out[:-1])
i = j + 1
@pytest.mark.skipif(
not (_CAPTURES / _DOWNLOAD).is_file(),
reason="capture is gitignored; present only on a dev box",
)
def test_replaying_thors_session_reproduces_every_byte_and_decodes_every_event():
"""The whole point of step 4.
Feed THOR's own responses to `iter_events()` + `get_event()`, and assert:
* every request byte we emit matches THOR's, in order
* all six events decode
* each waveform's decoded PVS matches the device's stored float
"""
reqs = list(_destuffed((_CAPTURES / _DOWNLOAD).read_bytes(), True))
rsps = list(_destuffed(
(_CAPTURES / _DOWNLOAD.replace("raw_bw", "raw_s3")).read_bytes(), False))
# THOR's session opens with commands our client does not send (POLL, 0x1C,
# 0x06 …) and ends with a delete. Take the contiguous run from the first
# 0x93 to the last 0x5A -- that is the event walk, and it is what we mirror.
subs = [p[2] for _, p in reqs]
lo = subs.index(0x93)
hi = len(subs) - 1 - subs[::-1].index(0x5A)
want_wire = [w for w, _ in reqs[lo:hi + 1]]
replay = [bytes([STX]) + stuff(p + bytes([checksum(p)])) + bytes([ETX])
for _, p in rsps[lo:hi + 1]]
# ⚠ THOR never reads the chain sentinel in this capture -- it downloaded
# exactly six events and stopped, so it knew the count in advance. It read
# `SUB 0x06` (storage range) at frame 7, BEFORE the walk, and that response
# begins `00 00 00 06` -- the event count. Our generator walks until the
# sentinel instead, so append one and compare only the overlapping frames.
replay += [frame(0x6C, bytes(11)), frame(0xE0, chain_entry(bytes(4), 0))]
# serial() would emit a 0x15 that is not in this slice, so prime the cache.
t = ScriptedTransport(replay)
mm = MicromateClient(t, recv_timeout=1.0)
mm._serial = "UM12947"
decoded, checked = 0, 0
for ref in mm.iter_events():
# Pin THOR's chunk size: this test asserts byte-identity with
# THOR's frames, and our default is 16x larger.
result = mm.get_event(ref, chunk_size=1024)
decoded += 1
assert ref.serial == "UM12947"
assert ref.filename and ref.filename.endswith(ref.suffix)
if not ref.is_histogram:
err = mm.decode_error(ref, result)
assert err is not None
assert abs(err) < 1e-4, f"{ref.uid}: PVS off by {100 * err:+.4f}%"
checked += 1
assert decoded == 6, "four waveforms and two histograms"
assert checked == 4
# Our trailing sentinel read is two frames THOR did not send; everything
# up to it must match byte for byte, in order.
assert t.written[:len(want_wire)] == want_wire, (
f"we emitted {len(t.written)} frames, THOR emitted {len(want_wire)}"
)
assert len(t.written) == len(want_wire) + 2, "only the sentinel read is extra"
@pytest.mark.skipif(
not (_CAPTURES / _DOWNLOAD).is_file(),
reason="capture is gitignored; present only on a dev box",
)
def test_a_corrupted_stored_peak_is_caught_by_the_self_check():
"""Prove the verify path actually fires -- otherwise it is decoration."""
reqs = list(_destuffed((_CAPTURES / _DOWNLOAD).read_bytes(), True))
rsps = list(_destuffed(
(_CAPTURES / _DOWNLOAD.replace("raw_bw", "raw_s3")).read_bytes(), False))
subs = [p[2] for _, p in reqs]
lo = subs.index(0x93)
hi = len(subs) - 1 - subs[::-1].index(0x5A)
replay = [bytes([STX]) + stuff(p + bytes([checksum(p)])) + bytes([ETX])
for _, p in rsps[lo:hi + 1]]
t = ScriptedTransport(replay)
mm = MicromateClient(t, recv_timeout=1.0)
mm._serial = "UM12947"
for ref in mm.iter_events():
if ref.is_histogram:
mm.download_event(ref, chunk_size=1024) # keep the replay in step
continue
ref.peak_vector_sum_ips *= 1.5 # as a bad decode would look
with pytest.raises(DecodeMismatch, match="decode is suspect"):
mm.get_event(ref, chunk_size=1024)
return
pytest.fail("no waveform event found in the capture")
tests/test_micromate_protocol.py
+148 -12
View File
@@ -174,12 +174,13 @@ def test_download_reproduces_thors_chunk_sequence_byte_for_byte():
payload = payload[:SIZE_4A81] payload = payload[:SIZE_4A81]
responses = [] responses = []
for i in range(4): for i in range(4):
want = min(P.CHUNK_SIZE, SIZE_4A81 - i * P.CHUNK_SIZE) want = min(P.THOR_CHUNK_SIZE, SIZE_4A81 - i * P.THOR_CHUNK_SIZE)
body = payload[i * P.CHUNK_SIZE: i * P.CHUNK_SIZE + want] body = payload[i * P.THOR_CHUNK_SIZE: i * P.THOR_CHUNK_SIZE + want]
responses.append(frame(0xA5, bytes(11) + body, page=want // 256)) responses.append(frame(0xA5, bytes(11) + body, page=want // 256))
p, t = proto(responses) p, t = proto(responses)
got = p.read_event_file(bytes.fromhex("055d4a81"), SIZE_4A81) got = p.read_event_file(bytes.fromhex("055d4a81"), SIZE_4A81,
chunk_size=P.THOR_CHUNK_SIZE)
assert t.written == REQ_CHUNKS_4A81 assert t.written == REQ_CHUNKS_4A81
assert got == payload assert got == payload
@@ -198,11 +199,12 @@ def test_chunk_count_and_final_offset(size, n_chunks, last_offset):
"""The first six rows are the six bench events, with THOR's real offsets.""" """The first six rows are the six bench events, with THOR's real offsets."""
responses = [] responses = []
for i in range(n_chunks): for i in range(n_chunks):
want = min(P.CHUNK_SIZE, size - i * P.CHUNK_SIZE) want = min(P.THOR_CHUNK_SIZE, size - i * P.THOR_CHUNK_SIZE)
responses.append(frame(0xA5, bytes(11) + bytes(want))) responses.append(frame(0xA5, bytes(11) + bytes(want)))
p, t = proto(responses) p, t = proto(responses)
p.read_event_file(bytes.fromhex("055d4a81"), size) p.read_event_file(bytes.fromhex("055d4a81"), size,
chunk_size=P.THOR_CHUNK_SIZE)
assert len(t.written) == n_chunks assert len(t.written) == n_chunks
# offset is payload[4:5] of the request; recover it from the built frame # offset is payload[4:5] of the request; recover it from the built frame
@@ -214,17 +216,29 @@ def test_chunk_count_and_final_offset(size, n_chunks, last_offset):
) )
def test_a_short_chunk_raises_rather_than_truncating(): def test_a_short_chunk_is_absorbed_and_the_remainder_refetched():
"""A silently short event is the failure mode this codebase keeps hitting.""" """⚠ Changed 2026-10-02: a short chunk is no longer an error.
p, _ = proto([frame(0xA5, bytes(11) + bytes(900))]) # asked for 1024
with pytest.raises(ShortRead, match="asked for 1024 B, got 900"): It used to raise, on the principle that a silently short event is the failure
p.read_event_file(bytes.fromhex("055d4a81"), 1024) mode this codebase keeps hitting. But the device *legitimately* returns
short — it clamps an over-large request to 16,384 B without saying so — and
the real protection is tracking the offset by bytes received, which makes a
short response cost one extra request instead of corrupting the file. The
total length is still checked, so a genuinely truncated event still raises.
"""
p, t = proto([frame(0xA5, bytes(11) + b"\xaa" * 900),
frame(0xA5, bytes(11) + b"\xbb" * 124)])
got = p.read_event_file(bytes.fromhex("055d4a81"), 1024,
chunk_size=P.THOR_CHUNK_SIZE)
assert got == b"\xaa" * 900 + b"\xbb" * 124
assert len(t.written) == 2, "the 124 B remainder was refetched"
def test_a_chunk_too_short_to_hold_its_header_raises(): def test_a_chunk_too_short_to_hold_its_header_raises():
p, _ = proto([frame(0xA5, bytes(4))]) p, _ = proto([frame(0xA5, bytes(4))])
with pytest.raises(ShortRead, match="too short to hold a chunk header"): with pytest.raises(ShortRead, match="too short to hold a chunk header"):
p.read_event_file(bytes.fromhex("055d4a81"), 1024) p.read_event_file(bytes.fromhex("055d4a81"), 1024,
chunk_size=P.THOR_CHUNK_SIZE)
def test_download_rejects_a_nonsense_size(): def test_download_rejects_a_nonsense_size():
@@ -391,7 +405,8 @@ def test_every_captured_download_frame_is_one_we_would_have_sent():
for e in events: for e in events:
p, t = proto([bytes([STX]) + stuff(r + bytes([checksum(r)])) + bytes([ETX]) p, t = proto([bytes([STX]) + stuff(r + bytes([checksum(r)])) + bytes([ETX])
for r in e["rsps"]]) for r in e["rsps"]])
got = p.read_event_file(e["key"], e["size"]) got = p.read_event_file(e["key"], e["size"],
chunk_size=P.THOR_CHUNK_SIZE)
assert t.written == e["reqs"], ( assert t.written == e["reqs"], (
f"event {e['key'].hex()}: our {len(t.written)} frames differ from " f"event {e['key'].hex()}: our {len(t.written)} frames differ from "
f"THOR's {len(e['reqs'])}" f"THOR's {len(e['reqs'])}"
@@ -400,3 +415,124 @@ def test_every_captured_download_frame_is_one_we_would_have_sent():
total += len(e["reqs"]) total += len(e["reqs"])
assert total == 56, f"expected 56 download frames across the 6 events, saw {total}" assert total == 56, f"expected 56 download frames across the 6 events, saw {total}"
# ── Above 64 KB: the limit UM20147 already exceeds ────────────────────────────
def test_chunk_offsets_carry_past_64_kb():
"""⚠ The offset is a uint32 at params[0:4], not a uint16 at params[2:4].
Every offset THOR was observed to send fits in two bytes (largest 0x3400),
so params[0:2] was always zero and the field looks narrower than it is.
Reading it as a uint16 caps a download at 65,536 B — and UM20147 holds a
72,560 B event, so the cap is not hypothetical.
This is the Series III 64 KB page-boundary bug in a new guise; that one is
still open. An address field whose high bytes are zero in every capture is
not a narrow field, it is an untested one.
"""
key = bytes.fromhex("055d4a83")
# Below the old cap: byte-identical to the uint16 form, so nothing verified
# against THOR's frames changes.
for off in (1024, 13312, 65535):
assert chunk_params(key, off) == bytes(2) + off.to_bytes(2, "big") + bytes(6)
# Above it: the carry lands in params[1].
assert chunk_params(key, 65536) == bytes.fromhex("00010000") + bytes(6)
assert chunk_params(key, 71680) == bytes.fromhex("00011800") + bytes(6)
def test_a_chunk_offset_with_0x10_in_it_is_escaped_on_the_wire():
"""At offset 1 MiB params[1] is 0x10, which must go out as `10 10`.
Nothing below 64 KB can produce this, so it only became reachable with the
uint32 offset — and an unescaped 0x10 is the bug class that cost the
Series III `5A` walk a release.
"""
params = chunk_params(bytes(4), 1 << 20)
assert params[:4] == bytes.fromhex("00100000")
from micromate.framing import build_request
frame = build_request(P.SUB_BULK_DOWNLOAD, 0x0400, params)
assert bytes.fromhex("1010") in frame
def test_a_72kb_event_downloads_in_71_chunks():
"""UM20147's event 055d4a83, the one that broke the uint16 assumption.
✅ Confirmed against the real unit 2026-10-01: 71 chunks, exact size, with
chunks 64-70 carrying 0x01 in params[1]. This test pins the arithmetic the
hardware agreed with.
"""
size = 72560
n = 71
responses = []
for i in range(n):
want = min(P.THOR_CHUNK_SIZE, size - i * P.THOR_CHUNK_SIZE)
responses.append(frame(0xA5, bytes(11) + bytes(want)))
p, t = proto(responses)
got = p.read_event_file(bytes.fromhex("055d4a83"), size,
chunk_size=P.THOR_CHUNK_SIZE)
assert len(got) == size
assert len(t.written) == n
# Chunk 64 is the first past the old cap; its params must carry the 0x01.
wire = t.written[64]
assert bytes.fromhex("000100") in wire, "the carry into params[1] is on the wire"
# ── The 16 KB ceiling, and the silent clamp ───────────────────────────────────
def test_default_chunk_size_is_the_measured_ceiling_not_thors():
assert P.CHUNK_SIZE == 16384
assert P.THOR_CHUNK_SIZE == 1024
def test_a_silently_clamped_response_is_absorbed_not_failed():
"""⚠ Ask for more than the device serves and it CLAMPS — silently.
Measured on UM20147: a 32,768 B request returns exactly 16,384 B of correct
data, no error. A loop striding by a fixed chunk size would either fail on
that or skip the bytes it never collected. Driving by bytes received makes
it a non-event: one more request.
Here a 20,000 B event is fetched with chunk_size=16384 against a device
pretending to clamp at 8192, so the walk must take 3 requests at
offsets 0 / 8192 / 16384.
"""
size, clamp = 20000, 8192
payload = bytes(range(256)) * 100
payload = payload[:size]
served, responses = 0, []
while served < size:
n = min(clamp, size - served)
responses.append(frame(0xA5, bytes(11) + payload[served:served + n]))
served += n
p, t = proto(responses)
got = p.read_event_file(bytes.fromhex("055d4a83"), size, chunk_size=16384)
assert got == payload
assert len(t.written) == 3, "two clamped requests plus the remainder"
def test_a_chunk_that_returns_nothing_raises_rather_than_spinning():
"""A byte-driven loop must not loop forever on zero progress."""
p, _ = proto([frame(0xA5, bytes(11))] * 4)
with pytest.raises(ShortRead, match="got none"):
p.read_event_file(bytes.fromhex("055d4a83"), 5000)
def test_the_72kb_event_now_takes_5_requests_not_71():
size = 72560
served, responses = 0, []
while served < size:
n = min(P.CHUNK_SIZE, size - served)
responses.append(frame(0xA5, bytes(11) + bytes(n)))
served += n
p, t = proto(responses)
got = p.read_event_file(bytes.fromhex("055d4a83"), size)
assert len(got) == size
assert len(t.written) == 5, "14x fewer round trips than THOR's 71"