Hallo Marko, > probably because they are trying to write to color RAM > ($d800-$dbff) but there is an index overflow. IMHO bad programming and that does not count. On second thought: how can a instruction like STA $D880,X store something in $D7XX even when X is, let's say, $CC? > In that expansion, I implemented it by connecting an > IRQ output of the 6821 PIA to one of its active-high CS inputs. So the moment you willingly generate an IRQ with this 6821, you are unable to address it anymore. Then how do you disable this IRQ? Otherwise you won't be able anymore to use the 6821 at all. (I understand that the 6821's IRQ is NOT connected to the system IRQ) Groetjes, Ruud http://Ruud.C64.org - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail cbm-hackers-request@dot.tml.hut.fi.
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