Re: 264/TED/Plus4 Story

From: Nate Lawson <>
Date: Wed, 24 Aug 2011 17:03:57 -0700
Message-Id: <>
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.


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Received on 2011-08-25 01:00:03

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