[sdiy] an XOR question

[Fredrik Carlqvist]

Oops!

Forgot to say that the other five inputs should be zero, ground, low. That
is, for the four logical inputs, A, B, C and D:

D'          V+
gnd    4    D'
out    0    D
gnd    5    gnd
gnd    1    gnd
gnd         C
gnd         B
gnd         A



Fredrik C

-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl] On Behalf Of Fredrik Carlqvist
Sent: Monday, September 13, 2004 10:06
To: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] an XOR question


Actually, a 8-input mux and an inverter is sufficient. (C-MOS cookbook,
Lancaster?) Take a 4051, wire A, B and C to the address inputs
(appropriately labeled A, B and C). Then lead D to input 1 and an inverted D
to inputs 2 and 4. Voila! Use a transistor for inverting and you’re done
with one IC.

Fredrik C


________________________________________
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl] On Behalf Of Schierl, Dan
Sent: Sunday, September 12, 2004 00:22
To: synth-diy at dropmix.xs4all.nl
Subject: [sdiy] an XOR question

Hi list--
I have an application I'm working on in which I need to perform an exclusive
OR on 4 inputs. Since I don't think anyone makes a 4-input XOR, I tried to
rig something up using some CMOS chips. My first attempt was a little too
simplistic (i.e. wrong), which I didn't realize until I'd already wired it
into my application. I think my second attempt works (haven't tried it yet,
tho) but i think it might be overkill. 
 
Go here: http://people.msoe.edu/~schierld/temp/xor.html to see my two ideas.
 
My question is: the second idea is pretty much a literal definition of an
XOR gate, but I wonder if there are any trick ways to make one of these with
fewer chips. Any thoughts you might have would be appreciated. thanks!