By polling INT0 flag bit... no interrupt handler
Code:
    ' INT0 polling with PWM
    ' =====================
    '
    ' File name :  INT0_poll_PWM.bas
    ' Company : Mister E 
    ' Programmer : Steve Monfette
    ' Date : 02/03/2005
    ' Device : PIC18F2320
    '
    '
    ' This program generate 3.6Khz @ 25% duty PWM on CCP1 pin.
    '
    ' CCP1 pin is connected to RB0 pin via 1k resistor.
    '
    ' Program blink a led on PORTB.6 while generating PWM.
    ' Each rising edge of PWM, PORTB.7 is toggle.  This will 
    ' generate 1.8Khz 50% duty on this PORTB.7 pin.
    '
    ' We will check INTCON.1 (Interrupt on RB0(INT0) flag bit) pin to 
    ' detect rising edge
    

    ' Hardware Definition
    ' ===================
    '
    DEFINE LOADER_USED 1
    DEFINE OSC 20
    
    TRISB=%00000001   ' PORTB.0 as input
    TRISC.2=0         ' PORTC as output
    ADCON1=$0F        ' disable A/D converter
    
    ' Interrupt definition
    ' ====================
    '
    INTCON=%00010000  ' Disable global interrupts
                      ' Enable INT0 interrupt (RB0)
    
    INTCON2.6=1       ' Enable INT0 on rising edge
    
   
    ' Variable definition
    ' ===================
    '
    Tmr2dutyvar VAR WORD
    DelayLoop   var word

    ' PWM signal generation
    ' =====================
    '
    
    Tmr2dutyvar=86 ' load duty time duration
    PR2=$57        ' load frequency period (PWM freq=3.6 KHZ)

        ' set Duty cycle
        ' --------------
        '
        CCP1CON.5=Tmr2dutyvar.1
        CCP1CON.4=Tmr2dutyvar.0
        CCPR1L =(tmr2dutyvar>>2)
        
        T2CON=%00000110 ' start timer 2
                        ' set prescaler = 16
    
        CCP1CON = %00001100 ' pwm mode for CCP1
    

    ' Main Loop
    ' =========
    '
    ' Stupid led blink on PORTB.6 while testing INT0 flag bit 
    '
Start:
      toggle PORTB.6
      for delayloop = 1 to 50000
          pauseus 5 
          if INTCON.1 then
             INTCON.1=0
             toggle PORTB.7
          endif
             
      next
      goto start