R.Belmont WIP [17-Jan-2006]

[Robert]

Source

 

Namco is insane

Phil Stroffolino was able to trojan and dump the BIOSes from the C71 3D math engine (actually a TMS32c025) and the C74 sound/inputs MCU (actually an M37702). He’s already flying high with the C71 - using that code many long-standing graphics problems are now gone and several games that didn’t work properly now work 100% (such as Ace Driver: Victory Lap).

 

The C74 is a bit more interesting. Unlike Super System 22, which has one M37710 (37710 and 37702 are the same MCU, just ‘02 has an internal ROM and ‘10 boots externally like a normal CPU), original System 22 has 2 M37702s (C74) with identical internal BIOSes. Based on the state of one of the MCU’s inputs, the BIOS boots one of 2 different programs. The first one, intended for the C74 on the I/O board, reads all the inputs, massages them, and transmits them via the MCU’s built-in serial port to the second MCU. The second MCU recieves the data via it’s own serial port, puts that in shared RAM for the 68020 to see, and handles all the sound and music duties.

 

There is no reason I can think of that you would *ever* design such an over-complex system - even “annoying emulator authors” wasn’t on their radar at the time. But anyway, I’ve gotta get back to making this train wreck work…