Den Mon, 16 Apr 2018 20:46:09 +0200 skrev Francesco Messineo <francesco.messineo@gmail.com>: > Hi Christian, > that makes sense indeed, I was too lazy to actually check a 2316/2716 > datasheet and the schematic seemed to imply I could put a 2532 in UD8 > too. So the 2001N addressing is much similar to the 2001, it doesn't > have I/O shadows each 256 bytes but it can't use the "free" addresses > for ROM. > Now it makes sense of course. Yes it would be much better to put the > I/O ports at $88xx, I can't even imagine why they didn't that in the > first place. Maybe someone foresaw a case for expanding the video RAM > to 4K in 1977? The really bad thing about the PET memory map is the placement of video RAM. Imho the optimal layout would had been, from top to bottom, kernal, i/o + video ram, basic rom, and from bottom and up general ram. That way you could have bank switched out basic in a future version and have continuous ram. With the 8096 and 8296, video ram sits there right in the way making ram non-continuous (unless you don't want anything usable displayed). Best Regards / Captain Obvious ;) ;) -- (\_/) Copy the bunny to your mails to help (O.o) him achieve world domination. (> <) Come join the dark side. /_|_\ We have cookies.Received on 2018-04-16 22:00:02
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