/* www.microDigitalEd.com
 * p2_5.c Read a switch and write it to the LED.
 *
 * This program reads an external SW connected to P1.1 and writes
 * the value to the red LED on P2.0.
 * When switch is pressed, it connects P1.1 to ground and bit 1 of
 * P1IN reads as '0'. P1.1 pin pull-up is enabled so that it is high
 * when the switch is not pressed and bit 1 of P1IN reads as '1'.
 * The LEDs are high active (a '1' turns ON the LED).
 *
 * Tested with Keil 5.20 and MSP432 Device Family Pack V2.2.0
 * on XMS432P401R Rev C.
 */

#include "msp.h"

int main(void) {
    P1->SEL1 &= ~2;         /* configure P1.1 as simple I/O */
    P1->SEL0 &= ~2;
    P1->DIR &= ~2;          /* P1.1 set as input */
    P1->REN |= 2;           /* P1.1 pull resistor enabled */
    P1->OUT |= 2;           /* Pull up/down is selected by P1->OUT */

    P2->SEL1 &= ~1;         /* configure P2.0 as simple I/O */
    P2->SEL0 &= ~1;
    P2->DIR |= 1;           /* P2.0 set as output pin */

    while (1) {
        if (P1->IN & 2)     /* use switch 1 to control red LED */
            P2->OUT &= ~1;  /* turn off P2.0 red LED when SW is not pressed */
        else
            P2->OUT |= 1;   /* turn on P2.0 red LED when SW is pressed */
    }
}