Re: visual 6502 simulation...

From: Rhialto <>
Date: Thu, 16 Sep 2010 18:02:23 +0200
Message-ID: <>
On Thu 16 Sep 2010 at 10:38:30 +0200, "André Fachat" wrote:
> I voted for the 6522 as next chip to analyze, to find out about the
> shift register bug.

Speaking of shift register bugs: there is this one that I don't remember
being explained. If you enable sound on a PET, then try to load anything
from cassette, the PET hangs. The STOP key does not work, nor does
anything actually load.

The sound is the shift register shifting
out bits to the CB2 pin, controlled by a timer.

POKE 59466,15		E84A shift register value
POKE 59467,16		E84B control register
POKE 59464,freq		E848 timer

which also notes "NOTE: Location 59467 must be reset to zero for
cassette to function properly". But that shift register isn't used for
cassette loading, right?

> André
___ Olaf 'Rhialto' Seibert  -- There's no point being grown-up if you 
\X/ rhialto/at/    -- can't be childish sometimes. -The 4th Doctor

       Message was sent through the cbm-hackers mailing list
Received on 2010-09-16 17:00:14

Archive generated by hypermail 2.2.0.