Re: cbm 8032 io area $e800-$e8ff decoding

Um, i meant $E900-EFFF if you use a 2k Edit rom.

Steve


> On Nov 9, 2016, at 4:38 PM, Steve Gray <sjgray@rogers.com> wrote:
> 
> 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
> 
> 
> 
> 
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> 
> 


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