New Toyz

[steve.ridley at bbc.co.uk]

The SGS M112 is a "Polyphonic Sound Generator" - uP controlled
dividers, ADSRs and VCA, various footages available with or
without envelope, 32 level digital drawbar control, percussion on
highest footage.  Basically it's an organ on a chip.  It's in the 1988
SGS-Thomson Audio & Radio ICs databook or try their website.
Get back to me if you're still stuck.

SSM2045 - 2/4 pole VCF with 2 VCAs arranged as a mixer (shared
output pin).
Pinout - 	1) 2 Pole out
	2) Sig in
	5) Fc
	8) 4 pole out
	9) Gnd
	10) -Vee
	11) Mix 1 -in
	12) Mix 2 +in
	13) Mix out
	14) Expo mix 
	15) Lin Mix 2
	16) Lin Mix 1
	17) Q control
	18) +Vcc
	2, 4, 6 & 7 are for filter caps.

 I think early Siel DK80s used the SSM2044 ( a "folded" transistor 
ladder).

TDA1022 - Bucket degrade line. 

MM5437 - Pseudo random noise generator.

SSM2031 - V-F converter.  Usually used as a master oscillator in
DCO synths.  Typically, it would be used as a fast VCO, with mod
and pitchbend being applied.  The output would then be divided 
down by 8253 dividers, or in this case the M112, to give the final
pitch.

I've got a schematic of the DK80 (the keyboard version) somewhere,
but it's massive - too big to photocopy.  I think I got it off Mark 
Glinsky.

Let me know if you need any more info


Steve Ridley