Intresting

docs/pt2-copy-state-machine.md

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+# PT2 Copy State Machine
+
+This is a focused reference for the COPY behavior seen on the RCP LCD and traced in the ROM.
+
+## Known Entry Points
+
+### Serial Start / Progress
+
+Frame:
+
+```text
+05 00 6D 00 00 32
+```
+
+ROM path:
+
+- Command 5 accepts selector `0x006D` at `BD80-BDBF`.
+- The selector is queued through `BE70`.
+- Selector `0x006D` dispatches to `H'3015`.
+
+Observed effects from forced decode:
+
+- Sets `F731.7`.
+- Sets `F795.6/F795.7`.
+- Loads `F798=H'C8`.
+- Sets display selector `F732=H'1903`.
+- Sets `FB02=H'64`.
+- Calls the display/report bridge at `48FA`.
+- Sets `F76E.6`.
+
+LCD dispatch:
+
+- `F732` high byte `0x19` selects `493E[0x19] -> H'930A`.
+- The local table at `H'931C` maps substate `0x03` to `H'9F6A`.
+- `H'9F6A` builds `COPY` / `IN PROGRESS`.
+
+### Serial Complete / Exit
+
+Frame:
+
+```text
+05 00 6C 00 00 33
+```
+
+ROM path:
+
+- Command 5 accepts selector `0x006C` at `BD80-BDBF`.
+- The selector is queued through `BE70`.
+- Selector `0x006C` dispatches to `H'2FAF`.
+
+Observed effects from forced decode:
+
+- Manipulates `F76E`, `F795`, `F797`, and `F799`.
+- Can set display selector `F732=H'1904`.
+- Sets `FB02=H'14`.
+- Calls the display/report bridge at `48FA`.
+
+LCD dispatch:
+
+- `F732` high byte `0x19` selects `493E[0x19] -> H'930A`.
+- The local table at `H'931C` maps substate `0x04` to `H'9FDA`.
+- `H'9FDA` builds `COPY` / `COMPLETED`.
+
+### RCP-Side Menu Start
+
+ROM path:
+
+- OTHERS menu page: `493E[0x01] -> H'631C`.
+- Local page table: `H'632E`.
+- `COPY TO SLAVES` entry handler: `H'6FF0`.
+
+Required gates:
+
+- The entry descriptor before `H'6FF0` requires `E400[0x0015] != 0`.
+- The local COPY action branch requires `F770.2` and `F791.7`.
+
+Local branch effects:
+
+- Sets `F76E.6`.
+- Sets `F795.7`.
+- Sets `F731.7`.
+- Loads `F798=H'C8`.
+- Sets `F711.7`.
+- Loads `F726=H'64`.
+- Calls `loc_5500`.
+- Displays `COPY TO SLAVES`.
+
+If `F770.2` is set while `F791.7` is clear, the ROM diverts through `H'704C` to a `SET RCP` / `MASTER` display path instead of starting copy.
+
+## Working State Model
+
+| State | Likely indicators | Entry | Exit |
+| --- | --- | --- | --- |
+| Idle / no copy | `F731.7` clear | Boot, timeout, or completion cleanup | `0x006D` or local COPY branch |
+| Copy in progress | `F731.7`, `F795.6/F795.7`, `F798` live, `F732=H'1903` | `05 00 6D 00 00 32` or local COPY branch | `0x006C` in the live window, or timer expiry |
+| Copy completed | `F732=H'1904` | `05 00 6C 00 00 33` while copy flags are live | Display/session timeout or next state update |
+| Timeout / not active | `F731.7` cleared by timer path | `F797` or `F798` reaches zero | Normal CONNECT recovery traffic |
+
+## Bench Results
+
+Observed on the real panel:
+
+```text
+006C alone                      -> CONNECT OK -> blank
+006D alone                      -> CONNECT OK -> COPY IN PROGRESS -> CONNECT NOT ACT
+006D -> 006C after 250 ms       -> COPY IN PROGRESS -> COPY COMPLETED
+006D -> 006C after 1.0-1.5 s    -> COPY IN PROGRESS -> COPY COMPLETED
+006D -> 006C after 2.0-2.5 s    -> COPY IN PROGRESS -> CONNECT NOT ACT
+006D repeated, then 006C        -> COPY IN PROGRESS held longer -> COPY COMPLETED
+006D repeated without 006C      -> COPY IN PROGRESS -> CONNECT NOT ACT
+```
+
+Current interpretation:
+
+- `0x006D` is a copy-start/progress-window refresh selector.
+- `0x006C` is a completion/exit selector that only behaves cleanly while the copy window is live.
+- The copy window is transient and timer-controlled.
+- The panel does not treat `0x006C` as a stateless "show completed" command.
+
+## Open Questions
+
+- What sets `F791.7` during normal CCU/RCP operation?
+- What exact official PT2 name belongs to selectors `0x006C`, `0x006D`, and `0x006E`?
+- Whether `0x006E` is a copy cancel/error sibling or an unrelated special selector.
+- Whether the CCU sends repeated progress refreshes during a real COPY TO SLAVES operation.