Re: 264/TED/Plus4 Story

From: Jim Brain <brain_at_jbrain.com>
Date: Wed, 24 Aug 2011 18:54:14 -0500
Message-ID: <4E558F26.8090906@jbrain.com>
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?

Jim

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

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