CCS/MSP432P401R: Get time in milliseconds, or configure system ticks

	
/*
 * -------------------------------------------
 *    MSP432 DriverLib - v3_21_00_05 
 * -------------------------------------------
 *
 * --COPYRIGHT--,BSD,BSD
 * Copyright (c) 2016, Texas Instruments Incorporated
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * *  Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * *  Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * *  Neither the name of Texas Instruments Incorporated nor the names of
 *    its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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 * --/COPYRIGHT--*/
/*******************************************************************************
 * MSP432 SysTick - Blink LED Program
 *
 * Description: This program will use the SysTick module to blink an LED with
 * a one second period. Once setup, the application will go into LPM3
 * mode and only wake up to toggle the GPIO pin.
 *
 * This program runs infinitely until manually halted by the user.
 *
 *                MSP432P401
 *             ------------------
 *         /|\|                  |
 *          | |                  |
 *          --|RST         P1.0  |---> P1.0 LED
 *            |                  |
 *            |                  |
 *            |                  |
 *            |                  |
 *            |                  |
 *
 * Author: Timothy Logan
 *******************************************************************************/
/* DriverLib Includes */
#include "driverlib.h"

/* Standard Includes */
#include <stdint.h>

#include <stdbool.h>

uint32_t millis(void);

volatile uint32_t Tick;

int main(void)
{
    /* Halting the Watchdog */
    MAP_WDT_A_holdTimer();

    /* Configuring GPIO as an output */
    MAP_GPIO_setAsOutputPin(GPIO_PORT_P1, GPIO_PIN0);

    /* Configuring SysTick to trigger at 1500000 (MCLK is 3MHz so this will make
     * it toggle every 0.5s) */
    MAP_SysTick_enableModule();
    MAP_SysTick_setPeriod(1500000);
    MAP_Interrupt_enableSleepOnIsrExit();
    MAP_SysTick_enableInterrupt();
    
    /* Enabling MASTER interrupts */
    MAP_Interrupt_enableMaster();  

    while (1)
    {
        MAP_PCM_gotoLPM0();
    }
}

void SysTick_Handler(void)
{
    MAP_GPIO_toggleOutputOnPin(GPIO_PORT_P1, GPIO_PIN0);
    Tick++;
}

uint32_t millis(void) { return Tick;}