/* www.microDigitalEd.com
 * p5_11.c using Timer_A2 as an event counter on pin P4.2
 *
 * The Timer_A2 is configured to use P4.2 as the clock. 
 * Clock input dividers are disabled. Timer counter TA2R 
 * is incremented for every pulse of P4.2. TA2 is configured
 * as up count mode and TIMER_A2->CCR[0] is set to 10. For every 10
 * pulses from P4.2, the CCIFG flag of TIMER_A2->CCTL[0] is set.
 *
 * The content of timer counter TA2R is read and dumped at
 * the tri-color LEDs so for every pulse of P4.2, the LED
 * color changes. For every 10 pulses, the red LED1 is toggled.
 *
 * Connect a 0V-3V low frequency signal to P4.2 and see 
 * the result.
 * 
 * Tested with Keil 5.20 and MSP432 Device Family Pack V2.2.0.
 */

#include "msp.h"

int main(void) {
    /* initialize P2.2-P2.0 for tri-color LEDs */
    P2->SEL1 &= ~7;           /* configure P2.2-P2.0 as simple I/O */
    P2->SEL0 &= ~7;
    P2->DIR |= 7;             /* P2.2-P2.0 set as output */
    P2->OUT &= ~7;            /* turn off all LEDs */

    /* initialize P1.0 for red LED1 */
    P1->SEL1 &= ~1;           /* configure P1.0 as simple I/O */
    P1->SEL0 &= ~1;
    P1->DIR |= 1;             /* P1.0 set as output */
    P1->OUT &= ~1;            /* turn off LED1 */

    /* initialize P4.2 as TA2CLK */
    P4->SEL1 |= 4;
    P4->SEL0 &= ~4;
    P4->DIR &= ~4;

    /* Configure TA2 as up counter using external clock, no input divides */
    TIMER_A2->CTL = 0x0014;     /* TA2CLK, ID = /1, up mode, TA clear */
    TIMER_A2->EX0 = 0;          /* IDEX = /1 */
    TIMER_A2->CCR[0] = 10;      /* set the flag every 10 pulses */

    while (1) {
        P2->OUT &= ~7;                /* turn off tri-color LEDs */
        P2->OUT |= TIMER_A2->R & 7;      /* set tri-color LEDs with counter value */
        if((TIMER_A2->CCTL[0] & 1) == 1) {   /* when the CCIFG is set (10 count) */
            TIMER_A2->CCTL[0] &= ~1;         /* clear the CCIFG flag */
            P1->OUT ^= 1;             /* toggle red LED1 */
        }
    }
}