[sdiy] x0x memories (TB-303, TR-606, TR-808)

[Mattias Rickardsson]

Hi,

I have some things that I must delve deeper into, and maybe you can help me.

The TB-303, TR-606, and TR-808 have a microprocessor (containing also the 
program code, I believe) and some memory ICs beside it (holding the 
pattern/song data, I believe).

Is this external memory used in such a way that it could be "emulated" by 
some other thing connected to the same microprocessor pins?

What I mean is basically this:
Does the 808 read the external memory ICs continously (like a sheet of 
music notes) while playing, so that an emulator could decide at any time 
what the next step should contain? Or is the external memory read in larger 
chunks, stored in the microprocessor while playing, and nothing can change 
it while playing?

(Has anybody done some neat tricks or analyses with this x0x memory 
architecture?)

Thanks!


/mr