cvs commit: src/sys/dev/ic via6522reg.h

Bernd Walter ticso at
Sat Dec 3 14:48:35 GMT 2005

On Sat, Dec 03, 2005 at 05:05:16PM +1100, Peter Jeremy wrote:
> On Sat, 2005-Dec-03 00:49:30 +0100, Bernd Walter wrote:
> >Mmmm - very interesting stuff - I used the 6522 as well as the 6821
> >on many self build 6502 and 68k based systems.
> ...
> >But honestly - I wasn't aware that a modern computer system still uses
> >them.
> You means things like nec765, i8237, NS8250, i8259, MC146818?  One of

No - I especially mean the 6522.
I grow up with C64 and C128 plus my first self build computers used
them, so there's a special relation.

> my work colleagues was surprised to discover that his brand new
> computer still uses peripheral chips (embedded in ASICs) that were
> designed before he was born...  Isn't backward compatibility a
> wonderful thing :-)

Only sometimes, we all know the bad sides with e.g. 8259 in modern

> At least back then the IC vendors would publish programming details...

And by moving them to ASICs also add more bugs...
I'm always surprised if someone manages to write a nec765 driver that
runs on all chips.

PS: to complete your list you'll have to add the 6845, 8254 and 8042.
Although I have to say that the 8042 lost it's feature as a general
purpose IO controler many years ago.

B.Walter                   BWCT      
bernd at                                  info at

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