If a simple timer is needed and the accuracy of 1 ms is sufficient, then you can use the TaskTimer.interface (Library).

' ------------------------------------------------------------------------
' title:  Example for the interface "TaskTimer" (library)
' hardware:  ateval-board von eHaJo.de
' change
' 2013-10-11 rgf - library
' --------------------------------------
const F_CPU = 8000000
avr.device = atmega32
avr.clock  = F_CPU
avr.stack = 84
 
#library "Library/TaskTimer.Interface"
 
#define LED1	as PortD.5
#define LED2	as PortD.6
 
LED1.mode	= output,low
LED2.mode	= output,high
 
TaskTimer.Init(Timer1,2,500) '2 Tasks, 500 ms
TaskTimer.Task(0)	= mytask0().Addr
TaskTimer.Task(1)	= mytask1().Addr
 
avr.Interrupts.Enable
 
do
loop
 
procedure mytask0()
  LED1.Toggle
endproc
procedure mytask1()
  LED2.Toggle
endproc