On Wed, Aug 30, 2023 at 5:34 PM Gerrit Heitsch <gerrit_at_laosinh.s.bawue.de> wrote: > > On 8/30/23 15:45, Francesco Messineo wrote: > > > FWIW, 8500 vs 6510 can be detected in software by checking how many > > cycles it takes for the unconnected port bits to decay from 1 to 0 > > level when the DDR is switched from output to input. > > I made a test ASM for proof of concept years ago. The decay time is > > also temperature dependent, but the 8500 is some (binary) order of > > magnitude slower due to probably much better gate insulation and lower > > die temperature (gate leakage depends on temperature). > > I remember a thread about that a few years ago and the outcome there was > that it's not reliable, the best 6510 are better than the worst 8500. So > you can only output a probability. > actually my test bed is very limited and all the 8500 I tested were much slower than any 6510 by far. I remember I had to add another 8 bits to the counter when I first tested the code on the 8500. However the code ran on other C64 was not always following this slow/fast pattern and I have no way to understand the differences if I don't have the actual machines around. I had the opportunity to test the code on a broken 8500 (bad I/O port only) and that was surely giving meaningless results. Frank >Received on 2023-08-30 18:02:15
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