segatools/doc/15093-06.txt

Reverse-engineered 15093-06 protocol
(somewhatlurker)


The host and device seem to communicate using data frames similar to (but not
the same as) jvs and the slider protocol.

In general, the host will issue a command to the device and the device will
respond using the same command number.
The response will have source and destination addresses swapped of course.

The host can request for future packets to not have responses, though this may
only affect certain commands such as LED data. Just something to be aware of
when implementing the system.


Basic packet format: `[sync] [dest] [src] [len] [data] [sum]`
sync: 0xe0
dest: destination address
src:  source address
len:  length of data
data: payload
sum:  sum of all prior bytes except sync

When the host requests something from/sends something to the board, [data] will
be `[cmd] ...`.
cmd: command number
(followed by arbitrary additional data if applicable)

When the board responds, [data] will be `[status] [cmd] [report] ...`.
status: status code
        (1: Ok, 2: SumError, 3: ParityError, 4: FramingError, 5: OverRunError,
        6: RecvBfOverflow)
cmd:    command number (same as the one from request)
report: report status code
        (1: Ok, 2: Wait, 3: ReportError, 4: ReportError)
(followed by arbitrary additional data if applicable)


Escaping:
Like in JVS, the sync byte and 0xd0 are reserved. To include these in data, send
0xd0 followed by the reserved byte minus 1. (ie. `d0 cf` or `d0 df`)


Addresses and game-specific details:
Chunithm uses 2 for the LED boards and 1 for the host. There's two boards
present, but they are differentiated purely by COM port (one COM10, one COM11).
Based on wiring diagrams, I think COM10 should be for the left half of the
marquee display (10 pixels * 5 columns) and the left partition lights (3 pixels).
COM11 should be for the right half (6 columns) and the right partition lights.
The marquee appears to snake strips back and forth (input of first column should
be at the top).

Ongeki seems to use 1 for the LED board and 2 for the host. It should be on
COM3.
I think the chain is left button (x2), lower left pillar (x7), left ring (x9),
upper left pillar (x7), top edge (x11), upper right pillar (x7),
right ring (x9), lower right pillar (x9), right button (x2).


Known Commands:
0xf0: get board info
    -- chunithm host sends command with no additional data (`e0 02 01 01 f0 f4`)
    -- respond with additional data `[boardno] 0a [chipno] ff [fwver] ...`,
       boardno and chipno are strings (seems same as slider protocol)
    -- ongeki uses 0a and ff as string terminators, not sure if that's the
       intended use though
    -- fwver can be found in an update filename (90 for chunithm, a0 for ongeki)
    -- there's probably some additional bytes like for slider board info, but
       I don't think they're important
    -- pad strings with 0x20 (important!)

0xf2: get firm sum
    -- respond with additional data `[sum_upper] [sum_lower]`
    -- sum can be found in an update filename (adf7 for chuni, aa53 for ongeki)

0xf3: get protocol version
    -- respond with additional data `[appli_mode] [major] [minor]`, appli_mode
       is bool
    -- version shouldn't matter much, but I think appli_mode should be 1
    -- try `01 01 04`

0x11: set timeout
    -- host will send with additional data `[timeout_upper] [timeout_lower]`
    -- respond with additional data `[timeout_upper] [timeout_lower]`
    -- 0 disables timeout
    -- presumably this makes the device reset if no data is sent for a certain
       time period, or maybe the device sends some kind of heartbeat within this
       period

0x10: reset
    -- host will send one additional byte (d9) to choose the reset code/type
    -- respond with no additional data

0xf1: get board status
    -- shouldn't be necessary to properly implement this, but if you must...
       host sends with additional data `[flagclear]`,
       respond with additional data `[boardflag] [uartflag] [cmdflag] [dipsw]`
    -- flagclear is a bool that presumably resets error flags
    -- flags are bitfields
    -- boardflag: `0 0 0 0 [bor] [reset] [timeout] [wdt]` (MSB first)
    -- uartflag: `0 0 [txoverflow] [rxoverflow] [overrun] [framing] [parity] [sum]`
    -- cmdflag: `0 0 0 0 [exe] [param] [unknown] [busy]`

0x14: set disable response
    -- host will send with additional data `[enable]`
    -- respond with additional data `[enable]`
    -- it looks like setting enable to true will _disable_ responses
    -- I think this makes the device not send responses for future commands
    -- it might only affect LED commands

0x82: set led direct
    -- host sends 66*3 bytes for rgb as additional data
    -- respond with no additional data

0x86: set led count
    -- host sends additional data `[count]`
    -- respond with additional data `[count]`
    -- probably just affects the output from the board to LEDs,
       neither chuni nor ongeki use this
    
0xfd: enter bootloader
    -- no real point implementing this, just interesting
    -- MCU might be an ATMega 32M1 btw, but I'm not sure