RE: Dumb EE question

        I have an even easier solution (Just use DeMorgan's law)

        You want:

        O = !A && B = !(A || !B)

      I'm not good at ASCII art, so I'll do my text best:
                       _________
        B---7402(1)*----| |
                      |7402(2) |------ O
      A---------------| |
                      ----------

(The * means connect B to both inputs of the first gate of a 7402 (quad NOR
gate))

Joe

-----Original Message-----
From: owner-vectorlist@synthcom.com
[mailto:owner-vectorlist@synthcom.com]On Behalf Of solarfox@texas.net
Sent: Tuesday, April 24, 2001 7:59 PM
To: vectorlist@synthcom.com
Subject: Re: VECTOR: Dumb EE question

On Tue, 24 Apr 2001 17:14:48 -0700 (PDT), you wrote:

>A B | O
>-------
>0 0 | 0
>0 1 | 1
>1 0 | 0
>1 1 | 0
>
>Is there a simple logic gate that will generate this output? Please don't
>say PAL... I don't have a programmer. ;-(

        Oh, god, no... a PAL would be _way_ overkill for this! (Frankly, I'd
fire any engineer who's first instinct was to use a PAL for such a simple
logic...)

>But if it could be done with standard gating fairly easily, let me know!

        Ask and ye shall recieve: :)

     1/6 7404
       1|\ 2 _____
A ------| >O-----| \
        |/ 1 | 1/4 |______ O
                 | 7408 |3
B ---------------|_____/
               2

        (Substitute appropriate logic family for the job at hand. :) ) Or, if
you don't mind a little extra propagation delay and would rather do it in a
single chip, then you can do this:

         _____
      _1| 1/4 \ 4 _____ _____
A ---|__| 7400 |O--------| 1/4 \ _9| 1/4 \ 8
       2|_____/ 3 ___| 7400 |O-----|__| 7400 |O-----
                     | 5|_____/ 6 10|_____/
B -------------------

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"There is no virtue in suffering fools gladly, for it only encourages them
to
persist in their foolishness." --Kehlog
Albran
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solarfox@DON'TMESSWITHtexas.net (Gary Akins
jr.)
http://lonestar.texas.net/~solarfox
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Received on Wed Apr 25 00:27:14 2001