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:
[mailto:
Sent: Tuesday, April 24, 2001 7:59 PM
To:
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 -------------------
----------------------------------------------------------------------------
-
"There is no virtue in suffering fools gladly, for it only encourages them
to
persist in their foolishness." --Kehlog
Albran
----------------------------------------------------------------------------
-
solarfox (Gary Akins
jr.)
http://lonestar.texas.net/~solarfox
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