The board you picture is the I/O work like mine and there is a similar board attached to the display (minus the USB ports and some variation in population of the PCB).
From what I've been reading there are various revisions of both the I/O and the LED control board. and compatibility changes with both of them.From what I understand the game pre-loads animations into the I/O board so that during gameplay it can just send simple commands such as "play animation #5". This makes sense because the JVS bandwidth is pretty slow and you'd have really laggy gameplay if the game board was providing the whole bit-stream for the display while polling the controls.
It looks like the communication between the LED control board and the I/O board is a simple Serial connection. Ideally I'd like to figure out if it's a 1 way output or if there is some kind of hand-shake communication that reports the LED control board revision/capabilities back to the I/O board and if it uses a standard/existing protocol for communication. ideally we could use an off-the shelf LED display/control board or worst case build one.
it could also open the possibility to improve compatibility across games that support it by reporting whatever hardware revision it wants to see.
If the I/O board does indeed store animations I'd suspect that it would be much more difficult to emulate, the JVS protocol is pretty well documented but I'd guess that these commands all reside in the "manufacturer specific" code range. so it'd be matter of recording the serial data and trying to make sense of it.
OK, just got home, did some more tests;
- Naomi via JVS, works very good
- System 256 with Tekken 5 via JVS, gives the mismatch error
- System 256 with Dragonball Z via JVS, works very good (no Namco animation here like the Tekken games)
If I hook up one of my working System 12 games you would get a message upon boot asking you to load the new display data for this specific game to the display, this process can take up to 10 minuntes or maybe more.
This data is stored until you pop in another board which contains 'display data' and then if would ask you the same upload confirmation.
I tried these things on any of the 'non-working' Namco JVS games:
- Turn OFF the display via the display's setting menu, same mismatch error
- Remove the s-video like connection cable between the JVS I/O and the display's PCB, does not boot at all. The cab also doesn't boot in this situation with working JVS games or Jamma games.
Here is the revision and the PCB of the display:
And this is the JVS I/O PCB:
This is the test screen from a Naomi:
This is the test screen from the System 256 with DBZ via JVS (JVS menu is grayed out):
and this is what I get when I boot Tekken 5 in the System 256:
I'd be interested in buying the memory card setup if I could find one as well. Would be really interested to know if there are any further differences with the change from CL1 to CL2.
There goes my desire to own one. Seriously supprising they didn't go with a Nanao MS2931 like Sega put in the Net Cities
based IOs was dumped
