The Roland CMU-800R is an analog synthesis add-on system for early 8-bit computers such as the Apple II or Commodore 64. The analog hardware provides four bass/melody voices which are said to be similar to Roland’s SH-101 or TB-303 circuits, and a drum set similar to the TR-606, although with very limited/no editability as-is. In addition there are 8 CV/gate outs, a clock in and out (which I assume is 16th note triggered) and four volume faders.
Sequencing and some voice editing is provided by software running on the host computer. A computer-specific add-on card connects to the CMU via a ribbon cable. Neither the card nor the software is available and no-one seems to have them. I’ve looked :
The plan is to bypass the onboard CPU and replace its signals with a MIDIbox Core and custom/adapted firmware, possibly based on the MBCV, SID and/or FM. This seems simpler than trying to reverse engineer the protocols to write to the machine via the ribbon cable, and should allow much more extensive modification into the future using MIOS. For example, MIOS control of mods and bends to allow more tonal variation, LFOs, ADSRs, groovebox SEQ ;D
I’ve attached the schematic below. When I’ve fully dismantled the unit, I’ll add scans of the two PCBs - a lower PCB hosts the CPU and I/O, and an upper one the analog voices and front panel hardware.
Sorry, the computer I was using yesterday clearly didn’t have the Asian fonts installed. All I could see was ?? ?? ? ?? ?? ?? ? ?? ? ? ?. And I cut and pasted it ::) Of course, I can see now that it’s not Polish
Don’t hold your breath for updates on this. There’s a couple of million other things I have to do before I get stuck in to it.
It occurs to me that the first thing to try and achieve is probably to get the CV/gates working.
Meanwhile, I’ll machine translate that website and see what I can dig out.
My bad. THIS pic seems to show how it connects to the motherboard:
Presumably the pins at the rear go into holes in the CMU’s PCB.
And the assembly code is there, which is nice, even if it is annotated in Japanese ??? Should be able to work out from that which pins to bang and when.
I got one NIB about a year ago, w/ the software, just need an Apple IIe to copy it and I’ll hook yall up, and yes I prefer to Midify it. Matrixsynth posted that jap link a while back also, I wouldnt even have the slightest clue on how to start, I’m just barely understanding on building the MB-Seq. I think I contacted Radio Junk box correctly but he probably just got an email that said ? ?
Update, I just checked Rjb’s blog and he has posted an update to this, I can barely understand the google jap to eng translation though. ASays there is some kind of re-shuffling problem
