Re: complete list of 6522/AY8910 registers ? (mockingboard)

[Michael Black <et472@ncf.ca>]

On Wed, 12 Sep 2012, BLuRry wrote:

> On Wednesday, September 12, 2012 2:20:17 PM UTC-5, (unknown) wrote:
> > On Wednesday, September 12, 2012 12:14:32 PM UTC-7, (unknown) wrote:
> >
> >
> >
> > > 6522 Chip #1,
> >
> > > -------------
> >
> > > add register # to $CX00, where X = slot # card is in
> >
> > >
> >
> > > IE, $C40A = Card in Slot4, 6522 #1 SR Shift Register
> >
> > >
> >
> > >
> >
> > > 6522 Chip #2,
> >
> > > -------------
> >
> > > add register # to $CX80, where X = slot # card is in
> >
> > >
> >
> > > IE, $C58C = Card in Slot5, 6522 #2 PCR Peripheral Control Register
>
> And just to make it more fun, the AY chips themselves have their own 
> registers which you use the ORA and ORB 6522 registers to access.  Let 
> me tell you, it was oh so much fun to develop emulation of this. 
> (sarcasm.. ;-)
The sound generator IC was originally intended for some General Instrument 
CPU if I remember properly, and with that the interface was simple.

Some other CPU and it became more trouble, which seems to be why most 
interfacing was done through a parallel interface IC like the 6522.

It's been a long time since I looked at the original datasheet, but maybe 
we just all jumped to that easy use of a PIA, without making any effort to 
directly interface the sound generator to a "foreign" bus.

   Michael