Thanks for the reply.  I understand this.  Sorry if I didn't make it clear.  
In order for this to work, as I understand it, there should be a high on the 
A1 PIC pin and when the button is pressed, the PIC should see it go low and 
then take A0 low in code.  The problem is that I can't get 5V on the A1 
line, it stays low no matter what I've tried as previously explained.  I 
figured putting a 10K pullup resistor to 5V on the A1 pin would give me a 
constant 5V on the A1 pin until the button is pressed but still it doesn't 
give me 5V on the A1 pic pin.
Thanks,
FJ


From: Kevin Timmerman <lists@pcmx.net>
Reply-To: "Microcontroller discussion list - Public." <piclist@mit.edu>
To: "Microcontroller discussion list - Public." <piclist@mit.edu>
Subject: Re: [PIC] one button on/off circuit problem
Date: Mon, 11 Jun 2007 22:30:57 -0400

A.1 is an input to the PIC so it can read the switch state.

To turn power off, set A.0 low.


At 09:46 PM 6/11/2007, you wrote:
 >Hi all,
 >I need to ask for help on something cause I obviously don't know what I'm
 >doing ;-)
 >
 >I took this circuit here:
 >http://www.pic101.com/pushpush.gif
 >And I replaced the pass transistor with a P channel FET.  I can get it to
 >turn on and latch with taking the pic pin A0 high, However I can't turn it
 >off by getting 5V on pin A1.  I put a 10K resistor on the A1 line to 5V 
but
 >don't get a high.  I tried it with the 4.7K from collector to Gate as 
shown
 >and without.  I tried a 1Mohm resistor from Gate to Source in place of the
 >10K.  No difference in any case.  I can't see a 5V signal at A1.  Help 
with
 >what I'm doing wrong is greatly appreciated.
 >Thanks,
 >FJ
 >
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