Date: 2002-10-30 10:13:52
Hi All, Many know about the trick of switching the PAL 64 to a the NTSC divider and increasing clock speed to 9/7 times (128%) of the standard speed (screen scrolls though). Last night I tried testing for how fast the over-clocking could go by socketing the 74193 divider on one of the early boards and changing the value that gets loaded into the counter. I found that 9/5 change worked (180%), whilst a 9/4 and so on didn't. This would suggest the basic components (65xx series) may be rated to 2MHz. Were the Commodore parts rated to this spec or just that a random sampling could cope with the higher speed? I'm not sure as to what stopped working at the higher clock rate... the board has 120ns RAMs so I guess these are Ok, but.... the board was just running the standard kernal routine, flashing the cursor at the and when the system was toggled back to the lower speed some of the characters on the display were corrupt suggesting a RAM problem? Also cursor had locked up, but that could be the CIA giving up.... Any thoughts? May be the ROMs? Cheers, 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
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