On Aug 24, 2011, at 4:54 PM, Jim Brain wrote: > On 8/24/2011 12:05 PM, Gerrit Heitsch wrote: >> On 08/20/2011 06:21 PM, Bil Herd wrote: >> >> >>> So there was ONE RULE when I got the Ted project, it has to have xxx number >>> of chips (I think it was nine chip) and no more, signed Jack Tramiel. Well >>> the TED’s reset circuit consisted of an RC circuit and a 7407. I proved it >>> wouldn’t work but I didn’t think about what this really meant as to who had >>> designed the computer (the answer was no-one had designed the computer at >>> that point) It was an easy argument to make that the computer would fail en >>> masse, we HAD to add a chip for reset, didn’t matter which chip, we simply >>> could not do it with a transistor or a 7407 gate. (yes I tried feedback to >>> create hysteresis ) The answer came back from the mountain that it was >>> okay to add a chip. I remember that people were stunned that I had >>> challenged this (some thought I would be fired) and won. >> >> That was the famous 555 timer chip if I read the circuit diagram right. Same way as the Reset was generated in the C64 on the older revisions. >> >> Thanks to whoever added the reset button to the 264. It always irked me that the C64 didn't have one. > If everyone else knows, can someone relate just WHY the original 7407 and RC would not work? My guess is that the edge wasn't sharp enough. Perhaps a Schottky part would have worked better. -Nate Message was sent through the cbm-hackers mailing listReceived on 2011-08-25 01:00:03
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