On 06/21/2017 07:12 PM, silverdr@wfmh.org.pl wrote: > >> On 2017-06-21, at 18:43, Gerrit Heitsch <gerrit@laosinh.s.bawue.de> wrote: >> >> Before you do that, check if there are other software detectable differences between the 6567R56A (and older) and the 6567R7 (and newer). Those might be easier to detect. > > As just noticed - there is a difference in the number of scan lines, which might in fact be easier to abuse. Yes, see if the line counter max values differ between them. >> I suggest this since it's possible by software if you have a 6569R1 or a later VIC and if later, if it's a 6569 or a 8565. >> >> Here's what Segher wrote about it: >> >> Excellent fun! It sees if the light pen interrupt can be triggered >> between raster lines x'136 and 2; if so, it's a 6569R1, if not, not. > > That's very interesting too! How does one trigger LP IRQ from within software alone? Is it a kind of raster position / CIA port combination? Well, the LP Input is connected to the joystick ports and shares a Pin with PB4 of the CIA on U1. So you can trigger LP IRQs via software. Gerrit Message was sent through the cbm-hackers mailing listReceived on 2017-06-21 18:02:52
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