/* Moving LED example

   CodeVisionAVR C Compiler
   (C) 2000-2007 HP InfoTech S.R.L.
   www.hpinfotech.ro

   Chip: ATmega128
   Memory Model: SMALL
   Data Stack Size: 128 bytes

   8 LEDs are connected between the PORTC
   outputs and +5V using 1K current
   limiting resistors
   The LEDs anodes are connected to +5V
   
   On the STK500 it's only necessary to
   connect the PORTC and LEDS headers
   together with a 10-wire cable
*/

// I/O register definitions for MEGA128
#include <mega128.h>


// quartz crystal frquency [Hz]
#define xtal 3686400
// moving LED frequency [Hz]
#define fmove 2

// the LED on PORTC output 0 will be on
unsigned char led_status=0xfe;

// TIMER1 overflow interrupt service routine
// occurs every 0.5 seconds

interrupt [TIM1_OVF] void timer1_overflow(void)
{
// preset again TIMER1
TCNT1=0x10000-(xtal/1024/fmove);
// move the LED
  led_status<<=1;
  led_status|=1;
  if (led_status==0xff) led_status=0xfe;
// turn on the LED
 PORTC=led_status;

}

void main(void)
{
// set the I/O ports
// all PORTC pins are outputs
DDRC=0xFF;

// turn on the first LED
PORTC=led_status;


TCCR1A=0x00;
TCCR1B=0x05;
TCNT1=0x10000-(xtal/1024/fmove);
TIFR = 0;
EIMSK = 0;

// Timer(s)/Counter(s) Interrupt(s) initialization
TIMSK=0x04;

// global enable interrupts
#asm
    sei
#endasm

// the rest is done by TIMER1 overflow interrupts
while (1);
}

int main(void)
{
   return 0;
}