On 2014-07-04 at 13:16:39, gerrit@bawue.de (gerrit@bawue.de) wrote: > The differences in the unassigned pages can be disregarded. It's like > reading from the unassigned address space in the C64, since there are no > drivers active, you get what the input stages see. That could be leftovers > from the last command or noise from other parts of the chip that is 'loud' > enough to be seen as '1' instead of '0' and combinations of both. > > In the C64 you usually get the last byte read by VIC since the traces have > enough capacitance to hold the voltage long enough. In the 6500/1 we're > talking about traces on the die itself. > > So, as long as the ROM part reads stable, we can disregard the rest. Yes, that was my question. If the remaining - chiefly ROM pages read all reliably. > According to the datasheet, the ROM is only 2 KB, so only pages 8 to F are > interesting, everything else is RAM, I/O or empty space. > > From looking at the last page, it looks like as if all 3 vectors > (IRQ,RESET,NMI) point to the same address $0A95, suggesting that IRQs are > not used in this implementation. That might help with the disassembly. Binary: https://dl.dropboxusercontent.com/u/58002657/cbm/1520/p8-pf.bin Infofile (pretty basic): https://dl.dropboxusercontent.com/u/58002657/cbm/1520/p8-pf.infofile Raw disassembly (infofile still crude): https://dl.dropboxusercontent.com/u/58002657/cbm/1520/p8-pf.s -- SD! Message was sent through the cbm-hackers mailing listReceived on 2014-07-04 13:00:02
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