DAC resolution

[Fraser, Colin J]

> -----Original Message-----
> From: jorgen.bergfors at idg.se [mailto:jorgen.bergfors at idg.se]
> Sent: 10 March 1999 07:10
> To: Colin.Fraser at scottishpower.plc.uk; synth-diy at mailhost.bpa.nl
> Subject: RE: DAC resolution
> 
> Would it be possible to make a small piggyback adapter and 
> use a 12 bit DAC with the Paia kit? If you're only going to 
> use the most significant 8 bits, I imagine it could be 
> possible. In that case, what DAC would be the best choice and 
> what do they cost?

I did this with one of the convertors I built for some friends.
They bought a Mini Korg 700, which has linear cv control.
To give the cv converter software selectable linear outputs, I built a
daughter board that plugged into the socket occupied by the 8 bit converter.

The daughterboard has a Burr-Brown DAC7801 12 bit DAC. This is accessed as 2
registers, so I just needed to add a fly lead from a processor address line
for register select, and make modifications to the software to write to the
top 7 bits for normal outputs, and write a 12 bit value from a look up table
for linear outputs.
If the source code for the MCV8 is available, you could probably do the same
thing, and add pitchbend too.

Colin f