I've recently bought this little synth toy, and i couldn't resist : i had to have a look inside. And do some reverse-engineering.
Here is the result : gutshots and preliminary schematic.
There are still missing parts, and probably errors, but most of the working principles are visible :
- The ATmega16 takes care of the "user interface", aka pots and leds, and also holds the program for the DSP (because he has the only Flash memory onboard)
- The Freescale DSP56364 gets the audio from the AKM4552 codec, and processes it in its internal memory
- Both processors are linked by a SPI link, which is mostly accessible at the programming header
- There are some oddities, such as Reset, NMI and MODB tied together, or the ATmega driving the output transistors ... the feedback loop of the first opamp looks strange too.
- The clock generator IC8 is unknown, the makings on the SOT23-6 package looks like CJ4R, or CU4R
Does anyone have improvement ideas, advice on dumping the SPI link, or error corrections ?