[sdiy] Old Computers

[Niels A. Moseley]

Hi,

>So I looked at Jarek's site and I see he uses a homemade 16 bit DAC, driven
>by 2 CMOS latches.  I wondered why we can't do the same with a printer
>port.  That totally removes the need for a soundcard altogether and the
>"dongle" would be extremely simple and trivial to program.  PCs have a
>built in programmable interrupt timer that can be set to interrupt
>regularly and an interrupt service routine could then calculate the next
>DAC value and present it.
>
>Has anyone approached this at all?

http://www.tkk.fi/Misc/Electronics/circuits/dacs.html

The interrupt routine has a lot of overhead. The 'covox speech thing' used 
this method and it was a cheap substitute for a Soundblaster around 1990.

Regards,
Niels.