Den Thu, 28 Dec 2017 15:44:13 +0100 skrev Francesco Messineo <francesco.messineo@gmail.com>: > > I don't have any idea why the 6540 needs the latch. An EPROM > > doesn't need one. > > it probably doesn't *need* a latch, they thought it would be useful in > some other architectures, before deciding it would be cheaper to add > more glue logic and use standard RAM/ROMs. > > If the 6540 latches addresses internally on rising edge of PHI2 it > means it can't easily be read on a standard programmer. Well, a standard eprom programmer would read the old adress when A0/PHI2 is low, and when A0/PHI2 goes high the 6540 would output correct content on the data bus. Thus you'll have to throw away every odd byte from the readout, but every even byte would be fine. This assumes that there are no noise on A1...Ax at the time A0 goes high. -- (\_/) Copy the bunny to your mails to help (O.o) him achieve world domination. (> <) Come join the dark side. /_|_\ We have cookies. Message was sent through the cbm-hackers mailing listReceived on 2017-12-29 01:00:03
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