/* www.MicroDigitalEd.com
 * p5_7.c Toggling blue LED using Timer32 with prescaler
 *
 * This program uses Timer32 with prescaler to generate 1 second delay to 
 * toggle the blue LED.
 * Master clock is running at 3 MHz. Timer32 is configured
 * with prescaler divides the incoming clock by 256. The
 * clock feeding the counter has the frequency of
 * 3,000,000 / 256 ~= 11719.
 * Since it is running at periodic mode, the counter reload is set to 11719-1 
 * to give a 1-second delay.
 * The blue LED is connected to P2.2.
 *
 * Tested with Keil 5.20 and MSP432 Device Family Pack V2.2.0
 * on XMS432P401R Rev C.
 */
#include "msp.h"

int main(void) {
    /* initialize P2.2 for blue LED */
    P2->SEL1 &= ~4;             /* configure P2.2 as simple I/O */
    P2->SEL0 &= ~4;
    P2->DIR |= 4;               /* P2.2 set as output */

    TIMER32_1->LOAD = 11719 - 1; /* set the reload value */
    /* prescaler divided by 256, periodic wrapping mode, disable interrupt, 32-bit timer. */
    TIMER32_1->CONTROL = 0xCA;

    while (1) {
        while((TIMER32_1->RIS & 1) == 0);   /* wait until the RAW_IFG is set */
        TIMER32_1->INTCLR = 0;      /* clear raw interrupt flag */
        P2->OUT ^= 4;               /* toggle blue LED */
    }
}