/*
 * lab3_base.c
 *
 *  Created on: Nov 27, 2017
 *      Author: johnsontimoj
 */

//////////////////////////////////////////////////
//
// Lab3 base - button - LED
//
// Turn on an LED based on button push
// no decision code
//
//////////////////////////////////////////////////

// Includes
#include "msp432.h"
#include <stdio.h>

#define clkcnt 3000000

void main(void){
	setbuf(stdout, NULL);	// fix code composer issue

    // Greeting code
    printf(" !! Lab 3 base program !!\n");

    // Local Variables
    uint8_t in_val1;
    uint8_t in_bit1;
    uint8_t P4_2_on;
    uint8_t P4_2_off;

    // Setup LED
    // Note: Port 4, bit 2 (P4.2) is pin 25
    //       |    bit 2
    // 7654 3210
    // 0000 0100  -> 0x04
    P4->DIR |= 0x04;        // Configure P4.2 as output by setting to 1 in DIR
    P4->OUT &= 0xFB;		// initialize the LED to off by setting to 0 in OUT
//  P4->OUT &= ~0x04;		// alternate way to turn off

    // Setup button
    // Button pushed - pin -> 0
    // Note: Port 1, bit 5 (P1.5) is pin 7
    //   |        bit 5
    // 7654 3210
    // 1101 1111  -> 0xDF
    P1->DIR &= 0xDF;		// Configure P1.5 as input
//  P1->DIR &= ~0x20;       // alternate way to set to 0

    // Infinite Loop
    while(1){
        // Read the button
        in_val1 = P1->IN & 0x20;		// read input port and isolate bit 5(0 or 32)
        in_bit1 = in_val1 && 1;			// get logical value for bit 5 (0 or 1)

        // Prepare to output to the LED
        // Here we don't want to change any other bits in the output port
        // Note - this approach is in-efficient but instructive
        P4_2_on = P4->OUT | 0x04;   // define required 'on' output - only sets P4.2 to 1, others unchanged
        P4_2_off = P4->OUT & ~0x04; // define required 'off' output - only sets P4.2 to 0, others unchanged
        // output required value (one side or the other of the addition = 0)
        P4->OUT = (P4_2_on * (!in_bit1)) + (P4_2_off * in_bit1);

        printf("%i\n", in_bit1);

        __delay_cycles(clkcnt/4); // 250ms
    } // end while

    return;
} // end main