/* www.microDigitalEd.com
 * p2_6.c Display number 75 on a 2-digit 7-segment common cathode LED.
 *
 * The segments are driven by Port4.
 * The digit selects are driven by P5.1 and P5.0.
 *
 * Tested with Keil 5.20 and MSP432 Device Family Pack V2.2.0
 * on XMS432P401R Rev C.
 */

#include "msp.h"

void delayMs(int n);

int main(void) {
    const unsigned char digitPattern[] = 
        {0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D, 0x7D, 0x07, 0x7F, 0x6F};

    P4->SEL1 &= ~0xFF;      /* configure P4 as simple I/O */
    P4->SEL0 &= ~0xFF;
    P4->DIR |= 0xFF;        /* P4 set as output */

    P5->SEL1 &= ~3;         /* configure P5.1, P5.0 as simple I/O */
    P5->SEL0 &= ~3;
    P5->DIR |= 3;           /* P5.1, P5.0 set as output pins */

    while(1){
        P5->OUT &= ~1;              /* deselect ones digit */
        P4->OUT = digitPattern[7];  /* display tens digit */
        P5->OUT |= 2;               /* select tens digit */
        delayMs(8);
        P5->OUT &= ~2;              /* deselect tens digit */
        P4->OUT = digitPattern[5];  /* display ones digit */
        P5->OUT |= 1;               /* select ones digit */
        delayMs(8);  
    }
}

/* delay milliseconds when system clock is at 3 MHz */
void delayMs(int n) {
    int i, j;

    for (j = 0; j < n; j++)
        for (i = 750; i > 0; i--);      /* Delay */
}