On 4/14/2011 2:00 PM, MikeS wrote: > Well, I dumped all 4 ROMs that I have and they match Zimmer's images > perfectly. > > ***BUT*** > > These ROMs are programmed with an active-HIGH chip select (pin20), so > a 2764 > (or even a 68764/6) would presumably need to have CS inverted. I think > this > issue has also come up in the C64/C128 world somewhere... > > If he didn't account for that then I'm surprised he read anything at all, > not just "substantially different" code ;-). That was news to me. All of the 2364 pinouts I have ever seen had pin 20 as active low. The only reference for that is from this list a decade ago: http://www.softwolves.com/arkiv/cbm-hackers/1/1399.html But, the information: 1 NC 28 VCC 2 A12 27 S3/-S3/NC (PROGRAMMABLE) 3 A7 26 S4/-S4/NC (PROGRAMMABLE) 4 A6 25 A8 5 A5 24 A9 6 A4 23 A11 7 A3 22 S2/-S2 (PROGRAMMABLE) 8 A2 21 A10 9 A1 20 S1/-S1 (PROGRAMMABLE) 10 A0 19 Q7 11 Q0 18 Q6 12 Q1 17 Q5 13 Q2 16 Q4 14 GND 15 Q3 Doesn't add up to me. 2364s have never had 28 pins. It looks like I'll need to create a new version of the adapter that uses a hct86 to optionally invert the pin 20 signal. Message was sent through the cbm-hackers mailing listReceived on 2011-04-16 04:00:13
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