[sdiy] Moog Memorymoog clone almost completed

[MTG]

What CPU did Oberheim switch to for Xpander? Is that 6809? I seem to 
recall some 6809 products (lovely CPU) and also vividly remember 
repairing a sample playback unit (DPX1?) that had a loose 68000 floating 
around in the chassis.

GB


On 10/16/2020 1:00 PM, Brian Willoughby wrote:
> Hola Luís,
> 
> I was going to ask whether you rewrote the firmware for your Memorymoog clone, but your more recent email replies show that you're still using a Z-80 and EPROMs. I would be tempted to modernize the CPU since it shouldn't affect the sound. Of course, it's much faster to duplicate the original CPU and code, and you have plenty of work on such a clone already. I'm just assuming that costs would be lower, performance might be higher, and power consumption would be lower with a modern embedded processor.
> 
> If you ever start on that Xpander project, drop me a line. I've been digging into the firmware (*) for the Matrix-12, which is basically the same as the Xpander, and I'm fairly familiar with the schematic.
> 
> Brian
> 
> * The Xpander firmware expends many cycles of CPU to keep those vacuum fluorescent displays refreshed. Meanwhile, the replacement displays for the Xpander also expend a lot of effort to translate the vacuum fluorescent signals into something that a modern LCD can work with. I was thinking that it might be worthwhile to rewrite the display code in the Xpander so that it talks directly to the LCD replacement, rather than wasting so much power on both ends ciphering and deciphering needlessly. Of course, such a rewrite would *only* work with the replacement LCDs, and not the original vacuum fluorescents, but it might improve the MIDI response or other aspects of the non-display code on such an old, 8-bit, low-speed CPU.
>