>> 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. > > Did they change the video timing or just the legal lines an LP IRQ > can be triggered? On my 1084 monitor, the welcome screen looks OK > no matter what VIC I use. Neither; look at my later message. >> The discrete vs. CMOS core logic thing seems to check whether >> flipping >> the VIC address space (VA15,VA14) glitches (doesn't on the CMOS). > > In what way does the old PLA design cause a glitch? I don't know :-) >> 6526 vs. 8521 CIA checks exactly how long it takes a timer to trigger >> (8521 is a clock cycle earlier it seems). > > Hm? From what I read everywhere, the HMOS-CIA (8521 or 6526 after > week 4x in 1986) takes an extra cycle with the timer IRQ compared > to the NMOS 6526. That is quite possible. Note the "seems" etc. > When testing a C64, I use the type check program mentioned above > plus a RAM test and the 'Edge of Disgrace' demo. The latter has a > few 'plasma' effects and on those you notice that they were written > for a 9-luma VIC. On the 6569R1 they look less smooth. You could just switch the monitor to greyscale :-P > To bad no one has yet been able to find a software trick to > distinguish between the 6510 and the 8500. :) They didn't? I thought you could do the timing thing with the high port pins? Very unstable of course... Segher Message was sent through the cbm-hackers mailing listReceived on 2011-12-10 20:00:03
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