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

[Nate Lawson]

Bernd Walter wrote:
> On Sat, Dec 03, 2005 at 12:32:49AM +0100, Wilko Bulte wrote:
> 
>>On Fri, Dec 02, 2005 at 10:36:14PM +0000, Peter Grehan wrote..
>>
>>>grehan      2005-12-02 22:36:14 UTC
>>>
>>>  FreeBSD src repository
>>>
>>>  Added files:
>>>    sys/dev/ic           via6522reg.h 
>>>  Log:
>>>  Register definitions for the ancient via6522. This 20+ year-old chip
>>>  still exists as a cell in the Macio asic on Apples, and is used to communicate
>>>  through the shift register with the external PMU microcontroller.
>>
>>Ah... our famous Versatile Interface Adapter chip!  I'm more familiar
>>with the 682[01] but this one is nicer ;)
> 
> 
> Mmmm - very interesting stuff - I used the 6522 as well as the 6821
> on many self build 6502 and 68k based systems.
> Usually a single 6522 to get system timers and then 6821 for firther
> GPIO.
> Since it's only a small step to the 6526: can we expect a C64 port
> soon ;-)
> But honestly - I wasn't aware that a modern computer system still uses
> them.

I still use one all the time in my Commodore 1541 floppy drive.  :)  The 
6522 showed up as a chip in the original Macintosh (and an Apple II 
mouse card) and then the core of it was integrated into various VLSI chips.

http://www.folklore.org/StoryView.py?project=Macintosh&story=Apple_II_Mouse_Card.txt
http://folklore.org/StoryView.py?project=Macintosh&story=Macintosh_Prototypes.txt

-- 
Nate