Hi Ruud, Ruud Baltissen wrote: >> - when the C64 hang up, I saw pop up lines on the screen once about every >> second at random places. These lines have the hight of one character and are >> filled with graphical nonsence but plm. 80% is white. >> >> With one exception, I haven't even the slightest idea were to start the >> research. The exception is removing the 6526 to see if the strange behaviour >> still happens. So any idea or comment is welcome. >The visual errors seem to indicate that there is a bus problem with the >VIC-II chip, i.e. the CPU doesn't shut down properly when the VIC-II takes >over the bus, and then reads some crap. And with both chips driving the >address bus, it is clear that the CPU crashes. I don't know if the '816 is >able to tristate it's address lines like the 6510 does. How do you handle the >CPU shutdown? I agree with Nicolas. I've seen such a bus contention in build the DMA section of the circuit for my application. I eventually resolved it on the C64, but still have the problem (strangely) when I plug the card into a C128. Also strangely, I had less problems developing the card for a "B3" circuit board than I did for the "A" boards, so timing is slightly different. Try poking the vic to blank the screen before the load... this will limit bad-lines and may let you identify which part of the circuit is the problem. - Nick PLEASE TAKE NOTE: The contents of this email (including any attachments) may be privileged and confidential. Any unauthorised use of the contents is expressly prohibited. If you have received this email in error, please advise us immediately (you can contact us by telephone on +61 8 9441 2311 by reverse charge) and then permanently delete this email together with any attachments. We appreciate your co-operation. Whilst Orbital endeavours to take reasonable care to ensure that this email and any attachments are free from viruses or other defects, Orbital does not represent or warrant that such is explicitly the case (C) 2000: Orbital Engine Company (Australia) PTY LTD and its affiliates Message was sent through the cbm-hackers mailing list
Archive generated by hypermail 2.1.1.