A useful method is also to whip up everything you currently have in a driver, then send sysexes to mame and see what happens to the registers. You can even use the debugger to trace how the bytes move around.

Posting schematics, especially for old-enough-to-vote hardware, is not a problem. It's roms that are frowned upon in general.

Yamaha hardware of that time stored register values as rotating shift registers, where on every internal cycle all values move one step into the next register. Not only it uses roughly one third less transistors that a traditional static ram bit, but it gets rid of the address decoding entirely. The...

Heh, what I tend to do is patch the rom to add sysexes that do write-to-memory, read-from-memory and call a function at an address. From there I can tweak registers and see what happens. Done that to the psr540 and the mu100b.

Nice.

FWIW, I have a heavy suspicion that the register formats for the sound-related OPU internal registers is very, very similar to the sysex format. You can find the service manual (sadly without schematics) with the sysexes on elektrotanya IIRC.

OG.

While we're necroing interesting posts... I've just found out Sega in model 1/2 uses for a fast inverse an approximate inverse and a newton-raphson step. The newton-raphson step needs 2/x and 1/(x*x), which are both provided by a rom. So, what if there's an internal rom that provides not one but *tw...

wpiset, same syntax as wpset.

OG.

The programmatic control "API" for mame is very much lua at that point. It's nowhere near complete, but we welcome complements. So, for remote control, I guess the best would be to grab a lua module that provides whatever method you like best, require it from a lua script, and have fun. OG.