AVR-Chat

ECL was the high speed emitter coupled logic. Great speed, great amounts of 
heat. It was used quite a bit in military equipment for a period of time and 
supercomputers. Fell out of vogue.
D
----- Original Message ----- 
From: "Don Kinzer" <dkinzer@easystreet.com>
To: <AVR-Chat@yahoogroups.com>
Sent: Wednesday, August 31, 2005 6:29 PM
Subject: [AVR-Chat] Re: Pull down resistors??


>> The convention of using logic 0 for 0 volts and logic 1 for a high...
>
> Actually, there are several nested conventions.  One is positive logic
> vs negative logic.  In the former, the most positive voltage is a
> logic 1 while in the latter the most negative voltage is a logic 1.
>
> Once you adopt one of those major conventions you move on to
> establishing what voltage ranges will be recognized for each level as
> well as possibly an "indeterminate" region.
>
> One logic family that used positive logic but negative voltages was
> ECL.  The thresholds were something like -0.9V for a logic 1 and -
> 2.75V for a logic 0.  I have a faint recollection of some Digital
> Equipment Corp. logic cards that were implemented using DTL or RTL
> technology  that were negative logic but I can't recall the details.
>
> Don
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