I disassembled large chunks of the 264 kernal last year when I built my diagnostic tool, and I'm pretty confident the kernal doesn't read it, but I do, simply to check it's operation. :-) I've also had a couple of dead ones, but that's out of 20 boards or so and one of them I blew up myself. I have a pre-production +4 board where the key's on the user port edge connector have been cut back to front, so I plugged in the diagnostic harness upside down, sending 9v AC into places it was not designed for. :-/ Much as the stamps with the Queens head printed back to front, I'm hoping to sell this board for about $1,000,000 and retire early. :-) Rob On 17/06/2012 17:34, Gerrit Heitsch wrote: > On 06/16/2012 07:52 PM, Bil Herd wrote: >> Yep, seemed designed for a whole byte of data in that number of pins. >> Kind >> of glad they didn't try to embed more functionality by any kind of pin >> re-use or processor controlled commanding, would have been harder to use >> as a TTL'ish part. > > That reminds me... If I remember right, the 6529 used for the keyboard > port in the 264 series is only written to, never read (Correct me if > I'm wrong). That should make it possible to use a 74LS574 or the like > on a small adapter instead. Maybe with series resistors of a few Ohm > on the output pins. If I'm wrong an it's also read, it will be a bit > more complicated and need a bit of extra logic > > So far I haven't seen a dead 6529 anywhere, seems to be a very stable > chip, but it would be nice to have a generic replacement available. > > Gerrit > > > Message was sent through the cbm-hackers mailing list Message was sent through the cbm-hackers mailing listReceived on 2012-06-17 16:00:26
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