On Sat, Oct 19, 2013 at 06:51:35PM -0400, Steve Gray wrote: >Will Max support something bigger than 6116? I ordered a few cheap 32k >sram chips in sdip that don't take much room... Even if we cant use the >whole capacity. I do not see why not, you should be able to use part of it at least. The Max uses static RAMs. I guess you could decipher the maximum RAM map from the PLA equations somehow: http://www.zimmers.net/anonftp/pub/cbm/firmware/computers/c64/pla-906114-1.c http://www.zimmers.net/anonftp/pub/cbm/firmware/computers/c64/pla.c Given that the PLA inputs include address lines A12 to A15, I would expect the memory to be divided into blocks of 4096 addresses. Some 15 years ago, I experimented with the Ultimax mode on the C128. You can programmatically set the GAME and EXROM lines on the C128 MMU at the same time when switching to C64 mode. From that I remember that the character generator ROM would disappear from the VIC-II memory map and be replaced with floating data lines. I was trying to see what happens if both the processor and the video chip is accessing unconnected address space for several clock cycles, but did not spend enough effort to see how many cycles are possible. You can always do some bank switching on your own, like I did on the Vic Flash Plugin. Are the I/O1 or I/O2 signals available on the Max cartridge port? Even the Atari VCS 2600 cartridges can use some bank switching, even if the cartridge port does not distinguish reads and writes. I wonder how they are doing that, I guess watching for magic access patterns, such as read-modify-write instructions, accessing the same address three times in a row (1 read and 2 writes). Best regards, Marko Message was sent through the cbm-hackers mailing listReceived on 2013-10-20 07:00:05
Archive generated by hypermail 2.2.0.