bench test updates

README.md

@@ -45,6 +45,8 @@ To start the current emulator harness:
 .\.venv\Scripts\python.exe h8536_emulator_rx_probe.py --preset connect-lcd
 .\.venv\Scripts\python.exe scripts\bench_connect_lcd_sequence.py --port COM5 --relay-port COM6 --prompt-screen
 .\.venv\Scripts\python.exe scripts\serial_ack_probe.py --ack-frame "05 00 40 00 00 1F"
+.\.venv\Scripts\python.exe scripts\serial_scenario.py scenarios\ack-race-000-001.json --log captures\ack-race-000-001.txt --result-json captures\ack-race-000-001-result.json
+.\.venv\Scripts\python.exe scripts\serial_scenario.py scenarios\table-sweep-ack-000-07f.json --log captures\table-sweep-ack-000-07f.txt --result-json captures\table-sweep-ack-000-07f-result.json
 .\.venv\Scripts\python.exe h8536_emulator_bench_replay.py captures\bench-connect-lcd-sequence-20260525-214411.txt --assert-bench-parity
 ```
 
@@ -92,6 +94,8 @@ The real-device bench helper uses `pyserial`; install repo dependencies with `.\
 - Includes an RX command probe that boots until SCI1 RXI is serviceable, injects host six-byte frames through RDR/RDRF, can optionally schedule 38400 8N1 byte arrivals at real UART spacing, listens for device TX frames, and reports serial latch/table/LCD-buffer and emulated-LCD effects.
 - Includes a bench helper for replaying the emulator-derived CONNECT LCD frame sequence against the real device through COM5, with optional COM6 relay power cycling and timestamped capture logs.
 - Includes a bench ACK probe that reproduces the `01 00 00...` -> `01 00 01...` visible retry burst, waits for `07 80 40 20 90 2D`, then sends a candidate command-5 ACK and reports whether the target keeps repeating.
+- Includes a checksum-resynchronizing bench receiver that scans RX byte streams for valid six-byte frames, avoids common shifted-heartbeat false locks, and can fall back to the old fixed six-byte slicer with `--sync fixed`.
+- Includes a JSON scenario bench runner for repeatable multi-step serial tests, including low-latency ACK-aware command-1 probes that can send the current command-5 ACK candidate immediately after the retry frame appears, with explicit max-ACK/max-target guardrails.
 - Includes a bench-log replay harness that feeds recorded host TX frames back into the ROM emulator with bench-style UART byte timing by default and asserts parity against the real device's observed response/LCD state.
 
 Current serial observations:
@@ -227,6 +231,9 @@ python h8536_emulator_rx_probe.py --help
 - `h8536_emulator_rx_probe.py --uart-timing --uart-baud 38400 "04 00 00 80 00"`: inject all six host bytes with 8N1 wire spacing of about 260 us per byte, letting RXI/TXI/timers interleave; if the ROM has not cleared `RDRF` before the next byte, the SCI model raises `ORER`.
 - `h8536_emulator_rx_probe.py --preset connect-lcd`: replay the current CONNECT LCD activation candidates.
 - `scripts\serial_table_dump.py --port COM5 --relay-port COM6 --start 0x000 --count 0x200 --log captures\table-read.txt`: read-only command-1 sweep of the firmware-exposed serial table state for EEPROM/shadow inference.
+- `scripts\serial_scenario.py scenarios\ack-race-000-001.json --log captures\ack-race-000-001.txt --result-json captures\ack-race-000-001-result.json`: run the focused `0x000 -> 0x001` retry probe with immediate reactive ACK and a 2 ms poll interval, to test whether command 5 can arrive before the second `07 80 40 20 90 2D` retry.
+- `scripts\serial_scenario.py scenarios\early-ack-000-001.json --log captures\early-ack-000-001.txt --result-json captures\early-ack-000-001-result.json`: send the same command-1 pair, then send command-5 ACK immediately without waiting for the retry frame.
+- `scripts\serial_scenario.py scenarios\table-sweep-ack-000-07f.json --log captures\table-sweep-ack-000-07f.txt --result-json captures\table-sweep-ack-000-07f-result.json`: run a repeatable bench scenario that sweeps selectors `0x000-0x07F` and sends `05 00 40 00 00 1F` only after `07 80 40 20 90 2D` appears. The checked-in scenario stops if it reaches 8 ACKs or 32 target hits. Use `--sync fixed` only when comparing against the old non-resyncing receiver.
 - `scripts\bench_connect_lcd_sequence.py --port COM5 --relay-port COM6 --prompt-screen`: power-cycle the bench device, wait for heartbeat readiness, send `04 00 00 40 00 1E`, `04 00 00 80 00 DE`, `04 00 00 C0 00 9E`, log RX/TX, and prompt for observed LCD text.
 - `h8536_emulator_bench_replay.py captures\bench-connect-lcd-sequence-20260525-214411.txt --assert-bench-parity`: replay a real bench log into the emulator using timed UART RX by default and intentionally fail while any response/LCD state still diverges from the bench-observed `CONNECT NOT ACT` plus `07 80 C0 60 20 5D` path. Pass `--polite-rx` for the old wait-until-consumed injection mode.
 - Current status: boots from `H'1000`, initializes SCI1, models the traced X24164 EEPROM bus on P9, captures P9 byte candidates, can optionally fast-path known P9 EEPROM routines, schedules FRT1/FRT2 OCIA from timer registers and `--clock-hz`, captures the ROM-driven LCD line ` CONNECT:NOT ACT`, and emits the observed heartbeat frame `00 00 00 00 80 DA`.
@@ -256,6 +263,7 @@ python h8536_emulator_rx_probe.py --help
 - `h8536/serial_pseudocode.py`: focused RX/TX protocol pseudocode generation from reconstruction metadata.
 - `h8536/protocol_trace.py`: raw six-byte protocol frame decoder/checksum validator.
 - `h8536/protocol_capture.py`: timestamped serial capture parser, frame recombiner, and cadence/gate-session analyzer.
+- `h8536/serial_scenario.py`: JSON-driven bench scenario engine shared by real-device serial scripts.
 - `h8536/serial_gate.py`: autonomous TX gate/queue state-machine reconstruction.
 - `h8536/report_source_trace.py`: direct `loc_3E54` report enqueue source tracer.
 - `h8536/table_xrefs.py`: table/index xrefs and LCD correlation report generation.
@@ -274,3 +282,4 @@ python h8536_emulator_rx_probe.py --help
 - `h8536_emulator.py`, `h8536_emulator_probe.py`, `h8536_emulator_rx_probe.py`, `h8536_emulator_bench_replay.py`: emulator CLI wrappers.
 - `scripts/bench_connect_lcd_sequence.py`: real-device COM5/COM6 bench runner for the CONNECT LCD sequence.
 - `scripts/serial_table_dump.py`: read-only COM5/COM6 command-1 table sweep for inferring live EEPROM-backed parameter state.
+- `scripts/serial_scenario.py`: JSON-driven COM5/COM6 bench scenario runner for chained probes, waits, read sweeps, and ACK-on-target experiments.