Turning an old PC into a MIDI-CV converter

Mikko H. MHELIN at tne01.tele.nokia.fi
Tue Mar 26 07:56:41 CET 1996


> From:	SMTP%"gstopp at fibermux.com" 25-MAR-1996 21:54:40.75
>
> (some good stuff deleted)
>      
>      The design uses an Analog Devices AD7228 Octal 8-bit DAC which is ...
.. available from Maxim (http://www.mxim.com) and Exar (www.exar.com). They 
have the same part, you can ask free samples directly from Maxim's web page. 
Part number for Maxim is MX7228 and for Exar MP7228.

>      installed in an external rack-mount panel that attaches to the PC via 
>      the parallel port. I chose the printer port over the serial port for a 
>      couple reasons:
>      
>      1. The external hardware would be less complicated 
>      2. The throughput would be higher
>      
You could also use a combination of the parallel port and a serial DAC 
(typically a 2 or 3-wire interface). Then you don't have to use control pins 
and possibly modify your parallel port (remove caps) at all. Programming could
be more difficult and data transfer slower (one bit at a time with clock bits
in between), but more DAC's could be used (serial clock can be usually shared 
and some serial DAC's can even be chained together and accessed thru the same 
3-wire interface).

-Mikko



More information about the Synth-diy mailing list