#include <msp430.h>
int c, start, ready;
unsigned long int a, b;
unsigned int t, dp;
void delay(unsigned int);
// display
void set_7segment(int nr, int dp);
const int seg7[] = {0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,
                    0x7f,0x6f,0x77,0x7c,0x58,0x5e,0x79,0x71};
#define reslow     (1638) // resolution 0,1  sec
#define reshigh    (819)  // resolution 0,05  sec

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
  P1DIR = BIT0;// output for display, Leds and Buzzer
  P1OUT = BIT0; // Led 3 and Led 4 off
//Setup Interrupt buttons
  //P1IE  |= BIT7;  // signal from S3 serves as interrupt
  P1IES |= BIT0; // active for high to low transition

// Setup Interrupt + Timer_A
  BCSCTL1 = 0x87;
  BCSCTL3 = 0x00;
  TACTL = TASSEL0 + TACLR;   // Timer A clock is ACLK + clear
  TACTL |= MC1;              // Timer A in Continous UP mode
  TACTL |= TAIE;             // enable interrupt at overflow
  TACTL |= ID0;// + ID1;     // TimerA overflow after 4 [2,8 or 16] seconds
  CCTL0 |= CCIE;             // enable CCR0 interrupt
  _EINT();                   // enable all active interrupts

  while(1)  // endless loop; game starts always
   {
     start=0; //ready=0;
     while (P1IN & BIT0); //    button  S1 not active
     a= TAR; // read count of Timer A
     b = a * 65521 + 12345;   // make an arbitrary value with TAR
     CCR0 = b % 32768;  // rest of dividing b by 32768
     if (CCR0 < 4000) CCR0 = 4000;
     start=0;
     TACTL |= TACLR; // Timer A  clear
     while(!start);       // wait for Timerinterrupt CCR0
     //CCTL0 &= ~CCIE;            // disable CCR0 interrupt

     P1OUT |= BIT0;  // buzzer on
     delay(1000);
     P1OUT &= ~BIT0;  // buzzer off
     P1IFG = 0; // for sure reset interrupt flag
     P1IE = BIT0;  // signal from S3 serves as interrupt
     ready=0;
     TACTL |= TACLR; // Timer A  Clear(TAR=0), start measurement
     while(!ready);       // wait for S3
     t=TAR;   // read count of Timer A
     c=t/reshigh; // resolution 0,05  sec
     if(c>15) { c=-1;dp=1;}
     else dp=0;
     P1OUT &=~BIT0;
     delay(65000);
     P1OUT |= BIT0;
     set_7segment(c,dp); // clear 7-segment display
   } // end while(1)
}    // end main()

#pragma vector=TIMERA1_VECTOR   // interrupt by timer-overflow, value
__interrupt void Timer (void)   // TAR = 65535; takes 4 seconds
  {
   P1OUT &= ~BIT0;  //Led 3 on
   delay(3000);
   P1OUT |= BIT0;  // Led 3 off
   TACTL &= ~TAIFG ; // reset interrupt overflow flag
  }

#pragma vector=TIMERA0_VECTOR  // counter TimerA reaches CCR0 value
__interrupt void timerA_Compare_IRQ(void)
{
  start=1;
}

#pragma vector=PORT1_VECTOR
__interrupt void knopactief(void)
{
  ready=1;
  P1IE = 0;    // interrupts port off
  P1IFG = 0;   // reset interruptPort flag
}

void delay(unsigned int k)
{
  unsigned int i;
  for(i=0;i<k;i++);
}

void set_7segment(int nr, int dp)
{
   P1DIR |= BIT0; // output for CLK  display
   int i;           // loop counter
   int segment = 0; // get segment code for the number to display

   if (nr > -1) segment = seg7[nr]; // get segment code
   if (dp)      segment |= 0x80;    // enable/disable decimal point
   P1OUT &= ~BIT0;  // clear bits just to make sure
   for (i = 7; i >=0; i--)
   {
      if (segment & (1<<i))
      {  // bit is set
         P1OUT |= BIT0; // set D serial-input
      }
      else
      {
         P1OUT &= ~BIT0; // clear D serial-input
      } // if
      P1OUT |= BIT0;     // set clock-input for at least 100 nsec
      delay(1);
      P1OUT &= ~BIT0;    // reset clock-input
      delay(1);
   } // for
   P1OUT |= BIT0; // All bits are transferred, now output to 7-segment display
   delay(1);
   P1OUT &= ~BIT0; // clear all bits
   P1DIR &= ~BIT0; // make P1.5 input for switch S1
}