Hi Marko, Will see if I can configure a dual EPROM cart with a switch on the GAME input. The upper ROM can call the lower one's cold vector. The RAM test will fail after the first 4k, but with a flick of the switch the normal config will be possible. I'll put a copy of the Kernal in the upper ROM just in case the car needs if for "printing" etc... Hopefully it doesn't need the BASIC ROM routines. - Nick >> >Since it is intended to test ROM, RAM, and I/O, there is no point starting >> >in the Ultimax mode and then switching. >> Except to maybe an idiot like me, if it has a black screen before and after >> the cartridge gets inserted I am no wiser as to whether its something simple >> like the Kernal rom or a reset problem :) >Exactly. The KERNAL ROM routine executes one RTS instruction before >jumping to the cartridge code. If the RAM at the top of the stack area >(somewhere around $1f0-$1ff) is broken, executing the RTS may fail. As >there are numerous other reasons for the screen remaining black, the >starting method applied by the cartridge is not very useful. 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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