Nope, there's no un-allocated space in that range. This has been my problem with my ColourPET project. Firstly, I use a 4K edit rom, which means the area from $E900-EFFF is used for that. Then I want to allocate $8800-8FFF for 80-column colour ram. If you use any option roms then $9xxx and $Axxx are out. That really doesn't leave anywhere in the memory map for anything else. So, assuming you dont have a ColourPET board (ha!) YOU could use $8800-$8FFF. It's free. If you are using a 2K Edit ROM you can use $E900-E9FF, however if you have a SuperPET it will use $EFEx-EFFF for it's memory control and ACIA chip. What I'm thinking of doing is making a board that mounts on the 6545 CRTC chip socket and intercepts the chip select signal, then runs it through a 3-8 decoder using A1,A2,A3. This will let me use output 0 for the CRTC and then I would have outputs 1-7 for my own use. Steve From: didier derny <didier@aida.org> To: cbm-hackers@musoftware.de Sent: Wednesday, November 9, 2016 3:30 PM Subject: cbm 8032 io area $e800-$e8ff decoding Hi Is there any solution to use in area between $e800-$e8ff to add extra chips ? (PIA / ACIA) ? is the decoding partial and standard chips shadowed or any free places ? -- didier Message was sent through the cbm-hackers mailing list Message was sent through the cbm-hackers mailing listReceived on 2016-11-09 22:00:02
Archive generated by hypermail 2.2.0.