'*******************************************************************************
'
' Copyright (c) 2008 Steve Vigneau <c0nsumer@nuxx.net>
'
' This software is provided 'as-is', without any express or implied
' warranty. In no event will the authors be held liable for any damages
' arising from the use of this software.
'
' Permission is granted to anyone to use this software for any purpose,
' including commercial applications, and to alter it and redistribute it
' freely, subject to the following restrictions:
'
'     1. The origin of this software must not be misrepresented; you must not
'     claim that you wrote the original software. If you use this software
'     in a product, an acknowledgment in the product documentation would be
'     appreciated but is not required.
'
'     2. Altered source versions must be plainly marked as such, and must not be
'     misrepresented as being the original software.
'
'     3. This notice may not be removed or altered from any source
'     distribution.
'
'*******************************************************************************
'
' This is for a PIC12F629 with config 0x3FD4.
'
' Changes state of GP0, preloaded with 0, every time GP4 changes, but only
'   if GP5 is high.
'
'*******************************************************************************

program synctest1

sub procedure interrupt()
  if GPIO.5 = 1 then ' Only if GP5 is high.
   if GPIO.0 <> 0 then ' Change GP0.
      GPIO.0 = 0
    else
      GPIO.0 = 1
    end if
  end if
  INTCON.GPIF = 0 ' Clear the interrupt on change flag.
end sub

main:
   CMCON = %111 ' Turn off comparitors.
   TRISIO = %110000 ' GP5:GP4 are inputs.

   GPIO.0 = 0 ' Preload GP0 to be low.
   IOC = %00010000 ' Interrupt on change of GP4
   INTCON = %10001000 ' Enable global interrupts and interrupt on change.

   while TRUE
   nop
   wend
end.