[sdiy] Module format

[Paul Maddox]

Tim,

> Is a removable/pluggable module necessary?

not really.
It would be nice to be able to swap one filter type for another, or one vco 
for a VCDO at a later date.

> My main question centers around
> how to create a user interface for something plugged into a SIMM socket. 
> If
> SMDIY modules are simply modern equivalents to CEM chips,

with the above in mind,

> but I have a feeling the 30 pins of the Dontronics SIMMSTICK won't be 
> enough
> I/O.

CEM/SSM tend to only be 14 or 16 pin packages, 30 pins should be more than 
enough.

> However, at this point, I feel like we're reinventing the
> wheel.

it depends on what the aim is.
IMHO, the aim shoudl be to rpdocue a 'range' of modules on a SIMM that 
people can pick and choose to integrate into their projects, or build 
complete synths from.
They don't have to be SIMM, they could be SIP or even DIP, but they should 
be a complete 'self contained' module.
I like JHs (I think it was him) idea about some modules like a bank of OTAs 
which people can do various things with. Again, 30pins is more than ample

> VME rack systems with pluggable modules have been around for years,
> and something like this seems to make a lot of sense to me.

have you seen the price of them?

> Basically, I like the idea of a small SIMM style backplane and modules, 
> but
> I wonder how the user interface would be implemented...

interface? thats down to the user and his/her application.
FWIW, my vote goes to a 30pin SIMM with a range of common supply rails 
(+15, -15 +5, GND), a set pins set aside for audio in (say 4), a set of pins 
aside for CV (again 4 should be ample) in and a set of pins for audio out (4 
again).
Given the above constraints, we're only using 16 pins of the 30 available..
So there's room to increase the pins use, for example 8 CV inputs, a 
DigitalGnd (to go with the 5V) and so on.

Grabbing the bull by the horns so to speak, how about this for pin use ;-

1 = AGND
2 = +15V
3 = -15V
4 = AGND
5 = +5V
6 = DGND
7 - 12 = Audio In (+5V to -5V)   Total of 6 audio inputs
13 = AGND
14 - 21 = CV In (+10v to -10v)   Total of 8 CV/Gate inputs
22 = AGND
23 - 30 = Audio Out (+5V to -5V) Total of 8 Audio outputs

this gives a MASSIVE cope for modules, for example, VC ADSR, VCO with CVs 
for lin FM, log Fm, PW, shape and multple output waveforms, VCF with 
multiple inputs and input mixer, a 6 input VC Mixer with panable outputs and 
so on.

Paul