----- Original Message ----- From: "A. Fachat" <email@example.com> To: <firstname.lastname@example.org> Sent: Tuesday, July 02, 2013 1:05 AM Subject: Re: (Fwd) Re: 8032 crt vs. 3032 crt > Am 2. Juli 2013 08:46:15 schrieb "MikeS" <email@example.com>: >> It turns out that there is a routine in the graphic ROM that checks for >> presence of the VIDEO ON signal on PB5 of the VIA that is not in the >> business version; the problem was a broken trace from the PIA to the VIA. > > Ah, a remnant of the old PET 2001 "don't access the screen memory while > displaying" code - that waited for retrace before printing to avoid snow > on the screen. > This code is also the cause for the speed up poke that turned into a > killer poke. > > Didn't think it was still in the Basic4 editor. > > André ----------------- You're right again; it isn't. I forgot to mention that the BASIC4 graphic ROM started to work for some reason, perhaps a bad socket; it was only the BASIC2 graphic ROM that was still hanging up waiting for that signal. m Message was sent through the cbm-hackers mailing listReceived on 2013-07-02 07:01:33
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