[sdiy] question re: microcontrol of synths...

[Luc Van Den Bosch]

Hmm, i did something similar a long time ago.
I used a C64 and a PIA (Paralel Interface Adapter) on the "memory expansion
port" (the right slot of the c64 where all kinds of cartridges could be
inserted)
The PIA has two 8-bit bidirectional ports (direction is programmable) and I
used 1 8-bit port for the CV signal and 1 bit of the other port fot the CV
signal.
The user interface was based upon that of the TB303, which means that you
could program 16 different measures that could be arranged into a track.
The first design had a internal clock that could be set to a certain BPM.
The second design used a SYNC input signal from a older Roland sequencer
(MSQ100) and the third was sync-able to midi.
The user interface was written entirely in Basic, but al the rest (driving
the PIA, sync-ing, reading and converting the CV-value's) was done in
assembler, and for timing purposes this was the only way to go.
CAUTION! in my later designs I used two seperate power supply's, one for the
digital stuff on the CBM64 side and one for the analog stuff on the
synthesizer (CV & gate) side.
Both sides were separated by opto couplers, the only way to ged rid of the
ever present digital noise on the GND of the C64.

If you're realy planning on building something like this I could send you
some scan's of the hardware and maybe something of the software.
Unfortunately I don't have the time to get into detail with this, even
finding the documentation of that project wil require some "digging" in my
archives.

Kind regards, Luc
http://users.pandora.be/lab-wan/index.htm



----- Original Message -----
From: Marcos San Miguel <electronophus at yahoo.com>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Thursday, November 08, 2001 11:29 PM
Subject: [sdiy] question re: microcontrol of synths...


> Does anyone know of a way to use an older micro (say a
> commodore 64 or TI99...something with a BASIC
> programming interface) to send CV/Gate to synths...I
> have seen it done (in fact there is a gentleman on
> musicsynthesizers.com with a picture of it happening)
> but can't find any information about HOW...want
> something less 'musical' than midi, but can't really
> afford the time/space/expense of a wall of analog
> sequencers/clock/boolean logic/sequential switches
> right now...
>
> sorry to bother y'all
>
>
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