Compiler/MSP430F5131: 1 PULSE PER SECOND CODE CHECKING

#include "msp430.h"
#include "intrinsics.h"

// defining flags as volatile(coz we use these variables in the main and in the ISR as well):
volatile unsigned int timerCount = 0; 	//defines the millisecond counter
volatile unsigned int normalPulse1=0; 	//defines another flag to indicates when 1 second has passed for normal pulse1
volatile unsigned int badPulse1=0;		//defines another flag to indicates when 1 second has passed for bad pulse1
volatile unsigned int normalPulse2=0; 	//defines another flag to indicates when 1 second has passed for normal pulse2
volatile unsigned int badPulse2=0;		//defines another flag to indicates when 1 second has passed for bad pulse2
volatile unsigned int secondsCount=0;	//defines the seconds count for the bad pulse


void main() { //Main function

	// configure watchdog timer:
	WDTCTL = WDTPW | WDTHOLD;					// Stop watchdog timer
	P2OUT &= ~(BIT4); 							//preload 1pps to '0'


	// set I/O pins directions:
	P1DIR |=BIT6+BIT7;                      //set p1.x to 11000000
	P2DIR |=BIT4;	                       // Set P2.4 to output direction
    PJDIR |=BIT0+BIT1+BIT3;                // set pj.x output 0000 1011
    P2SEL |= BIT4;						   //select the option of using TD0.0 in pin 2.4
    //P2IES |= BIT4;                         // high -> low is selected with IES.x = 1.
    //P2IFG &= ~(BIT4);                      // To prevent an immediate interrupt, clear the flag for
                                          // P2.4 before enabling the interrupt.
    //P2IE |= BIT4;                          // Enable interrupts for P2.4

    // Configure XT1 (external oscillator):
    PJSEL |= BIT4+BIT5;						// port select for xt1
    UCSCTL6 &= ~(XT1OFF); 				    //xt1 is on
    UCSCTL3 = 0;                            // FLL REFERENCE CLOCK REFERENCE = XT1

    // configure TD0.0 (TimerD0.0):
    TD0CTL0 |=MC_1+ID_3+TDSSEL_0+TDIE+CNTL_0+TDCLR;                //defining timer d TD0.0 (P2.4) upmode , devide by 8 , TDCLK , enable interupt , 
    TD0CCR0=1600-1;                          // setting TAR count up value 1600 (12.8MHz / 8 = 1.6MHz , 1.6MHz / 1600 = 1000 Hz) when 1000 is passed means 1 second has passed as well
	//TD0CCR1 =400-1;                           // setting the duty cycle to 25% pulse
    TD0CCTL0 |= CCIE;                        //ENABLES CCIFG INTERUPT ON CCR0
	//TD0CCTL1 |=CCIE;							//ENABLES CCIFG INTERUPT ON CCR1


    __enable_interrupt();    					//enables interupts in the ISR


    for(;;){                      // Main loop - Endless loop



    	//   EXTERNAL / INTERNAL SELECTION BY SW4

    	if ((P2IN & BIT2)==0){         //  INTERNAL MODE
		
    		PJOUT |=BIT3;              // sends '1' from pj.3 output to the multiplexer U4 (uses the internal 1pps)

    		//PULSE 1 : DESCRETE ON/OFF AND SWITCH ON/BAD/OFF

                     if ((P2IN & BIT0)==0 || (P1IN & BIT0)==0) {        //NORMAL SIGNAL OF 1PPS checks if descrete source is on or 1pps sw pulse 1 is on
                    	 P1OUT |= BIT6; 									//ENABLES PULSE BY THE 'AND' GATE
                    	 PJOUT |= BIT0;									//ENABLES TTL TO RS232 CONVERTER (FOR DIFF OUTPUT)
                          if(normalPulse1==1){                       //checks if normalPulse1 is on from the ISR
						    normalPulse1 =0;                           // sets normalPulse1 to 0 again so the ISR will generate the pulse 
						    P2OUT ^=BIT4;                            //generates 1pps out of p2.4
						 }

                	 }
                   
                     else {
                    	 P1OUT |= ~(BIT6); 								//DISABLES PULSE BY SENDING A '0' TO THE AND GATE
                     }

                     if ((P1IN & BIT2)==0)  {							//PULSE 1 BAD SIGNAL checks if the 1pps sw bad pulse is on
                    	  P1OUT |= BIT6; 									//ENABLES PULSE BY THE 'AND' GATE
                    	  PJOUT |= BIT0;									//ENABLES TTL TO RS232 CONVERTER (FOR DIFF OUTPUT)
						    if(badPulse1==1){                             //checks if badPulse1 is on from the ISR
							  badPulse1=0;                                // sets badPulse1 to 0 again so the ISR will generate the pulse
							  P2OUT ^=BIT4;                            //generates 1pps out of p2.4
							
							}
                     }

                     //PULSE 2 : DESCRETE ON/OFF AND SWITCH ON/BAD/OFF


                     if ((P2IN & BIT1)==0 || (P1IN & BIT0)==0){			//NORMAL SIGNAL OF 1PPS checks if descrete source is on or 1pps sw pulse 2 is on
                    	 P1OUT |= BIT7; 									//ENABLES PULSE BY THE 'AND' GATE
                    	 PJOUT |= BIT1;	 								//ENABLES TTL TO RS232 CONVERTER (FOR DIFF OUTPUT)
							if(normalPulse2==1){
								normalPulse2=0;								// sets normalPulse2 to 0 again so the ISR will generate the pulse
								P2OUT ^=BIT4;                            //generates 1pps out of p2.4
							
							}


                     }


    	
                     else {
                    	 P1OUT |= ~(BIT7);									//DISABLES PULSE BY SENDING A '0' TO THE AND GATE
                     }

                     if ((P1IN & BIT3)==0){								//PULSE 2 BAD SIGNAL 
                    	  P1OUT |= BIT6; 									//ENABLES PULSE BY THE 'AND' GATE
                    	  PJOUT |= BIT0;									//ENABLES TTL TO RS232 CONVERTER (FOR DIFF OUTPUT)
							if(badPulse2==1){
								badPulse2=0;								// sets badPulse2 to 0 again so the ISR will generate the pulse
								P2OUT ^=BIT4;                            //generates 1pps out of p2.4
							}
                     }


                     }

    	else {																//EXTERNAL MODE
    		PJOUT |= ~(BIT3);            //sends '0' from pj.3 output to the multiplexer U4 (uses the external 1pps)
    		P1OUT |= BIT6;      			// ENABLES PULSE 1
    		P1OUT |= BIT7;				//ENABLES PULSE 2
    		PJOUT |= BIT0;				//ENABLES RS422 DIFF OUTPUT	FOR PULSE 1
    		PJOUT |= BIT1;				// ENABLES RS422 DIFF OUTPUT FOR PULSE 2
    	    	}
    	}
		
}

	
	
                    //ISR FOR TIMERD0.0 - NORMAL/BAD PULSE 1 AND 2
					
					
					
					#pragma vector = TIMER0_D0_VECTOR 				//GENERATES 1PPS EVERY 1s for normal pulse
                   __interrupt void TIMER0_D0 (void){
					   
					   //NORMAL PULSE 1 AND 2:
					   
                	   if (++timerCount > 500) {   						// checks if the incrementation of timerCount reaches 500 (means 1 second has passed)toggling means doubling the time this is why we need to devide the time to a half. (1000/2=500)
					                      timerCount = 0;             // resets the millisecond counter to 0
							       normalPulse1 = 1;             //once it reaches 500 (1 second) normalPulse1 will be 1 
							       normalPulse2 = 1;				//once it reaches 500 (1 second) normalPulse2 will be 1 
								 secondsCount++;
                	                  	   }
                	                  	  
                     
					// BAD PULSE 1 AND 2:
					
				
                	   if (secondsCount == 2) {   						// checks if the incrementation of secondCount reaches 2 seconds for bad pulse (means 2 second has passed)
									secondsCount = 0;             // resets the millisecond counter to 0
									badPulse1=1;					// once it reaches 2000( 2 seconds) the badPulse1 will be 1.
									badPulse2=1;					// once it reaches 2000( 2 seconds) the badPulse2 will be 1.
                	                  	   }
                	                  	   
}