On 22/12/2016 10:16, Michał Pleban wrote: > Using these signals, you can create a simple latch which resides > somewhere in the SID address space and is used to select the appropriate > KERNAL. Upon reset, the latch would be reset to 0 to select the "KERNAL > selection KERNAL", which would write the desired KERNAL number to the > latch as well as a special bit to disable the latch until next RESET. Another method you can use is magic read sequences. i.e. come up with a sequence of rom reads that wouldn't happen in normal circumstances, long enough to make accidental activation so unlikely that it's practically impossible for there to be a collision. Then have the next read after this sequence use the address bits as data lines for writing the new bank. I've also seen this used in a battery backed real time clock that can be placed in a ROM socket, writing to the date/time registers was done using reads. Message was sent through the cbm-hackers mailing listReceived on 2016-12-24 01:00:03
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