[sdiy] SID questions...

[>>>marjan<<<]

Hi,

while we're on this topic - I've found sid chip and 8255 so I'm
considering
building parallel sid, but some things puzzle me:

1. There's missing clock input to sid at the schematic, do I need to
make
some with logic gates or something or you pull clock signal from
somewhere
else?

2. There are X and Y analog inputs, which measure RC constant and
convert
analog to digital for controllers. Now, I can't find info WHAT they do 
control inside the sid? I thought to put two pots on front panel for
real time editing, or some simple circuit that will convert CV to 
some RC time constant (some OTA app?).

3. External input - is it operational with the program given, it'd
be nice use it as ext processor too, just to make simple buffer
to input, or even some little pramp.

4. I'll make some single supply buffer at sid output, C64 used single
transistor emiter foll. (noisy?), but also I remember seeing somewhere
at Commodore sites one app that used 15kHz LPF made from lm324 at
the output. Good idea?


I've read sid datasheets and that sidtech pages online but still can't
figure these things...


Thanks,


marjan