sid chip 8580

[Michael Buchstaller]

>does anyone know if there are any important changes between the 6581/8580 
>chips? 

AFAIK the chips marked "8580" are those we all know as 6582. All of the later
C64s i have seen so far used to have them.

The only difference is said that the output amplifier power has been changed
from 12V in the 6581 to 9V in the 6582.
But another problem is that they have "improved" it so that the click when the
sound is switched on/off is gone. Some programs that had speech output via
sampled waveforms used this click to produce sound, so they will lack this
capability with the mewer sound chip. (i did not personally verify this, but read
rumors)

>and any way to simple test without needing a C64 or major 
>microcontroller?

You can hook it up to your PC´s parallel port. See my interface at
http://www.buchi.de/ParallelSID/
i have done this some time ago. The SID uses 5 Address lines for its
registers. together with the R/W, CS and Reset this accumulates to
8 control lines in addition to the 8 data bus lines, so it is not possible to
use the parallel port without some simple glue logic. You can either use
some latch, or build the 8255 circuit i have described. The latter one
simplifies it, because you will not have to write and test software for it,
you can download it from my web site.
 

-Michael Buchstaller