lab11.c

/* RealTime Clock.
 * Global variable msCount is incremented every millisecond by Timer 
 * channel 5 Interrupt Service Routine.
 * Loop in main displays msCount<15:12> on the module LEDs 
 * and msCount<11:4> project board LEDs.
 * Note that when a word is assigned to a byte variable, the low 8 bits
 * of the word are assigned to the byte.
 */

#include <hidef.h>      /* common defines and macros */
#include <MC9S12C128.h>     /* derivative information */


void initializePorts(void);
volatile word msCount = 0;
int i=0;
byte patterns[]={0x00,0x01,0x03,0x07,0x0F,0x1F,0x3F,0x7F,0xFF,0x7F,0x1F,0x0F,0x07,0x03,0x01,0x00};
word last_time=0;
volatile word delay=0x0080;

void readButtons()
{
	word delay_increment=0x10;

	if(PTM_PTM4 == 0) //up
	{
	
	    while(PTM_PTM4==0) 	{ ; }
	    
	    if(delay_increment<= delay)
	    {
	        delay-=delay_increment;
	    }
			else
			{
			
			  delay=0;
			}
			

	}
	else if(PTM_PTM5==0)//down
	{
   	while (PTM_PTM5==0) 	{ ; }
		delay+=delay_increment;

	}
}

void main(void) {
   initializePorts();
   EnableInterrupts;  // Equivalent to  asm CLI
  
   for(;;) {
  		// Display msCount<11:4> on board LEDs
     // PORTA = msCount >> 4; 
     
      readButtons();

  		// Display msCount<15:12> on module LEDs
      PORTB = ~(msCount >> 8);
     
  } 
}



void leds()
{
 
  
  word delta_from_last_update=msCount-last_time;
  
  if(delta_from_last_update>=delay)
  {
    
    PORTA=patterns[i];
    i++;
    last_time=msCount;
  }
  
  if(i>13)
  {
    
    i=0;
  }
  
  
}
/////////////////// Timer5 Interrupt Service Routine  /////////////
void interrupt 13 ISR_Timer5(void) {
   msCount++;
   
  
   leds();
  
   
   TC5 += 1000;   // Interrupt again in 1 ms
   TFLG1 = 0x20;  // Clear Timer5 Flag;  will not interrupt 
                  // again if flag is not cleared.
}  

void initializePorts() {
   DDRA = 0xFF;  	// PTA<7:0> - outputs	 (LEDs)
   DDRB = 0xF0;   // Make PTB<7:4> outputs
   TIOS = 0x20;    // Make IOC5 an output.  It is NECCESSARY to make 
                  // a timer bit an output (not of the chip, but of the
                  // internal Timer Block) in order to have it generate
                  // an interrupt request.
   TSCR1 = 0x80;   // Set TEN = 1 (Enable timer)
   TIE = 0x20;     // Turn on Timer5 interrupt; disable others
   TSCR2 = 0x01;   // Set Timer prescaler bits PR<2:0> to 001 
                  // and disable Timer Overflow interrupt.
                  // Timer counter clock = BusClock / 2 = 1MHz
}