Den Sun, 24 Mar 2019 02:30:39 +0100 skrev Michał Pleban <lists@michau.name>: > Hello! > > I cannot find the datasheets for 8563 and 8658 chips anywhere online. > Are they available? > > I am thinking about creating a graphics card with these chips for the > CBM-II line, and I am looking for pertinent information. So far, I was > not able to find answers to these questions: Some kind of guesses: > * What is the purpose of the CCLK pin, which is unconnected in both > C128 and C12DCR? Hook up an oscilloscope and check yourself! It might be a "color clock" intended for composite generation, and if so it would most likely need a suitable clock frequency that's some kind of multiple of the color frequency. > * The 8568 is said to have an output indicating that it has completed > the operation, which is unused in the C128DCR. Would it be the pin > number 8, which is unconnected and without description on the > schematic? Again, hook up an oscilloscope and see if something happens on that pin :) > * Would it be possible to run the chip at 18 MHz instead of 16 MHz as > in the C128, and what are the possible consequences of doing so? 12.5% higher clock frequency, I'd say that there is a fairly good chance for it to work. Maybe you could change the frequency of a C128 and see if that seems to work? Both a C128 and the B series runs the CPU bus at 2MHz, so that is really something you'd like to try anyways. -- (\_/) Copy the bunny to your mails to help (O.o) him achieve world domination. (> <) Come join the dark side. /_|_\ We have cookies.Received on 2019-03-25 10:00:04
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