View Full Version : Exclusive OR - XOR
Archangel
- 8th September 2006, 01:36
How would you go about using an xor function with 2 outputs, without using discrete logic IC followers, is this DOable in code? What I am seeking to do is combine 2 outputs as follows: output 1 logic hi or low depending on what it needs to output. output 2 would be a cycling hi/low signal. the output would either cycle opposite output 2 or output 1 in a steady state depending upon what output 2 is doing. I can do this using a 7486 xor gate, I would rather do it in code but have Zero Idea as to how.
Thanks Again
JS
RTFM / CONFUSED = DUMMY W / HEADACHE
Darrel Taylor
- 8th September 2006, 04:20
Hi Joe,
The XOR symbol is ^
Still not sure exactly what you're trying to do, but something like this might work...
PIN VAR PORTB.0
OUT1 VAR BIT
OUT2 VAR BIT
PIN = OUT1 ^ OUT2
HTH,
DT
Archangel
- 8th September 2006, 09:36
Thanks Darrel,
I'll see what I can do with tidbit.
Joe
blainecf
- 13th September 2006, 16:11
Please provide a "truth table" as example of what you expect:
Pin 1 Pin 2 Pin 0
0 0 ?
1 0 ?
0 1 ?
1 1 ?
bcf
Archangel
- 13th September 2006, 21:27
Hello,
Well something like this:
pin0 pin1 pin2
0 0 0
0 1 1
1 0 1
1 1 0
I want the pic to do exactly what a 7486 TTL chip will do
from signals generated by other code.
example:
sub1
portb.0 high
pause 500
portb.0 low
pause 500
return
sub2
if portb.1 = 1
then portb.0 high
else
return
I need to control 1 output xor from 2 inputs.
It's really simple to combine 2 outputs into a 7486 xor
chip to achieve this, but I am sure it can be done internaly
in a pic.. In the above example the first sub would always output
a flashing signal, whereas sub2 would output a steady signal only
if sub 1 was not running. I haven't had time to get back to this
but I have some ideas as to how to do it.
thanks for asking.
JS
ro37bis
- 14th September 2006, 09:44
hello test some like this:
PIN VAR PORTB.0
OUT1 VAR BIT
OUT2 VAR BIT
PIN = OUT1 ^^ OUT2 ' alternative syntax is PIN = OUT1 XOR OUT2
bye
Roberto
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