Hybrid systems MUSIC 5000

[Fraser, Colin J]

> -----Original Message-----
> From: Paul Maddox [mailto:Paul.Maddox at unilever.com]
> Sent: 03 December 1999 14:03
> To: synthdiy
> Subject: Hybrid systems MUSIC 5000
> 
>   I just got one of these, from what Ive read its a 16 voice
> synth which uses Phase-accumultor osc and wave playback
> from ram.
> 
>   what I dont have is a command list (and pin out for bbc 1mhz bus)
> so I can drive this thing, what I hope to do is to make it a midi
> polysynth :-)
> 
>   Anyone have any info on commands for loading ram, setting note
> , tuning, schematics... I think Colin Fraser may know a bit about
> these things.

Indeed.

What you have is basically a fixed program dsp.
It has 8 pairs of oscillators, with memory for holding 14 different
waveforms shared among all the voices, and registers for each oscillator to
hold level, pan, frequency, waveform select, ring mod and sync status.
All envelopes etc are generated by the host computer.
Data values are held internally as logs. The dac used is anti-log. This
allows multiply (dca) operations to be performed using adds, and gives the 8
bit system a s/n comparable to 12 bit.

I have a program that is supposed to access the hardware directly, so I
should be able to work out the memory map of all the registers etc. I
believe it works on a command & data type write only transfer from the host
cpu.

The output dac is multiplexed between all 8 voices. With a copy of the
schematics it should be possible to add individual outputs for each voice
and tack on analogue filters, but I've never seen a schema.
This is on an increasingly large pile of my 'rainy day projects'.

If you need a BBC micro to run it, I have a couple of spares.

Colin f