h8-536-decoder/ccu_emulator/README.md

PT2 Fake CCU

This folder contains a small modular fake-CCU runner for the Sony RCP PT2-style serial link.

The first goal is simple:

1. Open the RCP serial link at 38400 8E1.
2. Optionally wait for heartbeat.
3. Seed active selector-zero state.
4. Listen for complete RCP report frames.
5. Immediately answer report-looking frames with the neutral command-5 ACK:

05 00 40 00 00 1F

ROM and emulator evidence says this consumes the outstanding report cursor without triggering COPY or lamp/display side effects.

Run

Dry-run configuration:

.\.venv\Scripts\python.exe scripts\ccu_emulator.py --dry-run

Run against the bench RCP on COM5:

.\.venv\Scripts\python.exe scripts\ccu_emulator.py --port COM5 --duration 30 --log captures\ccu-keepalive.txt

Power-cycle first through the COM6 relay:

.\.venv\Scripts\python.exe scripts\ccu_emulator.py --port COM5 --power-cycle --relay-port COM6 --duration 30 --log captures\ccu-keepalive-powercycle.txt

Try the older three-frame CONNECT cadence seed instead of the command-0 active seed:

.\.venv\Scripts\python.exe scripts\ccu_emulator.py --seed connect-sequence --seed-gap 0.700 --duration 30

Optionally add periodic state refresh traffic:

.\.venv\Scripts\python.exe scripts\ccu_emulator.py --refresh-active --refresh-interval 0.600 --duration 30

Enable the bench-proven IRIS/M.BLACK LINK closed-loop module:

.\.venv\Scripts\python.exe scripts\ccu_emulator.py --iris-mblack-link --duration 60 --log captures\ccu-iris-mblack-link.txt

When the RCP reports selector 0x0013 as 0x4000 or 0x0000, this module sends:

05 00 13 00 00 4C  ; ACK selector 0x0013
00 00 13 40 00 09  ; mirror active, or 00 00 13 00 00 49 for clear

That matches the bench-proven IRIS/M.BLACK LINK state machine: the RCP reports local intent, the CCU acknowledges the selector, then the CCU mirrors the accepted state back so the next physical press toggles the other way.

Layout

• frames.py: checksums, built-in frames, and simple host-frame builders.
• iris_mblack_link.py: selector 0x0013 ACK-and-mirror state-machine module.
• modules.py: small protocol-module interface for feature-specific CCU behavior.
• policy.py: decides whether an RCP frame should be ACKed.
• refresh.py: optional periodic state-refresh scheduling.
• serial_link.py: serial read/write plus checksum-resync frame detection.
• controller.py: event loop and stats.
• cli.py: command-line entry point.

Why Periodic Lamp/Value Writes Help

Repeated button/lamp/status writes probably do play into the normal CCU flow. The ROM reloads the broad F9C5 session watchdog on every complete six-byte RX frame, and command-0/command-4/command-6 table writes refresh the selector tables that drive lamps, readouts, and menus.

So a real CCU likely does both:

• reactively ACK RCP reports so the report queue advances, and
• stream or refresh panel state so the visible UI remains current.

The first version keeps those concerns separate: reactive ACKs are always available, while periodic refresh frames are opt-in with --refresh-frame or --refresh-active.