On 8/10/2011 3:10 PM, Hoffmann-Vetter, Martin wrote: > Hello, > >> I don't know how relevant it is to CBM floppy drives, but it seems to >> have something to do with chip select lines? > That's one problem when you change an 2332 (rom) to a 2532 or 2732 (eprom). > The 23xx series has many chip select (cs) signals that can be programmed in > the polarity. So the standard 2332 for the PET is non inverted chip select > (cs1) at pin 21 and inverted chip select (cs2) at pin 20. You have the same > problem with some dos roms eg. 901887-01 and 901888-01. That's a 2364 with > one non inverted chip select at pin 20! > > Back to the 2332. This rom has two chip select inputs. The 2532 has only > ohne chip select input. The 2732 has one chip select and one output enable > input. So the 2732 is a better replacement for the 2332. It's used on the > adapter boards for the sfd 1001 and the 8250lp by commodore. > I spent this evening trying to augment my 2364 design to handle 2332 and 2364, including 2364 with positive CS. Comments are appreciated: Schematic: http://postimage.org/image/2n6tytt8k/ PCB: http://postimage.org/image/2n75jl8p0/ Message was sent through the cbm-hackers mailing listReceived on 2011-08-11 04:00:17
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