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#include <hidef.h>      /* common defines and macros */
#include <mc9s12c32.h>     /* derivative information */

#pragma LINK_INFO DERIVATIVE "mc9s12c32"

/***************************************************************
* Function prototypes
****************************************************************/
__interrupt void RealTimeInterrupt(void);

/****************************************************************
* Local data definitions
****************************************************************/
static volatile unsigned char rtiCnt;		/* to count number of RTIs */

void main(void) 
{
  DDRB = 0x01;				/* set portb pin 0 to output */
  PORTB = 0x01;				/* turn on LED connected to PB0 */
  RTICTL = 0x50;			/* 1/(4MHz/2^14) = 4.096 ms per RTI */
  CRGINT |= 0x80;			/* enable RTI interrupt */
  rtiCnt = 0;				/* RTI counter to 0 */
  asm("cli");				/* enable global interrupts */

for (;;) {				/* infinite loop */
    if (rtiCnt == 122) 
    {						/* 500 ms passed? */
      PORTB = ~PORTB;		/* toggle LED on/off */
      rtiCnt = 0;			/* reset rti counter */
    }
  }
} /* end main() */

__interrupt void RealTimeInterrupt(void)
{
  rtiCnt++;					/* increment the counter        */
  CRGFLG = 0x80;			/* clear rti flag               */
} /*end RealTimeInterrupt() */