http://www.mikroe.com/en/books/picbasicbook/06.htm#6.3

 
 

program Timer0_1sec

 
dim cnt as byte
dim  a as byte
dim  b as byte
 
sub procedure interrupt
 cnt = cnt + 1        ' Increment value of cnt on every interrupt
 TMR0   = 96
 INTCON = $20         ' Set T0IE, clear T0IF
end sub
 
main:
 
a = 0
b = 1
OPTION_REG = $84      ' Assign prescaler to TMR0
TRISB  =   0          ' PORTB as output
PORTB  = $FF          ' Initialize PORTB
cnt =   0             ' Initialize cnt
TMR0   =  96
INTCON = $A0          ' Enable TMRO interrupt
 
' If cnt is 200, then toggle PORTB LEDs and reset cnt
do
 if cnt = 200 then
   PORTB  = not(PORTB)
   cnt = 0
 end if
loop until 0 = 1
 

end.