[sdiy] pd650 - do all the Roland applicaitons use an identical chip?

[Rainer Buchty]

> What's worse, it seems they have no backup of the firmware. Last chip 
> gone, firmware gone. And AFAIK that goes for all their programmed 
> CPU's.

Hmmm... I wonder what's happening on ports C/D, if you power the chip on 
with TEST tied low instead of high, apply reset, and start clocking.

(They had to test the ROM contents somehow, right? And the only output 
pins in that architecture coming from the internal data bus, which 
"accidentally" also serves as instruction bus are ports C and D.)

Anybody taking the challenge? :)

Rainer