pmm_ex1_lpm4-5.c

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/*******************************************************************************
 * MSP430i2xx Power Management Module - Enter LPM4.5
 *
 * Description: In this example, the device is setup to enter LPM4.5. Before
 * the device enters LPM4.5 the LED is turned on to indicate it has entered
 * LPM4.5. Exiting LPM4.5 is triggered by a Low to High transition on P2.1 that
 * causes a reset of the device. Once reset the LPM4.5 interrupt is set and the
 * device begins to simply toggle the LED. This example demonstrates how to
 * setup the device for LPM4.5 and interrupt successfully from it.
 *
 *
 *                MSP430i2041
 *             ------------------
 *         /|\|                  |
 *          | |              P1.4|-->LED
 *          --|RST               |
 *            |                  |
 *            |                  |
 *            |              P2.1|-->Wakeup
 *            |                  |
 *            |                  |
 *
 * Author: Zack Lalanne
 ******************************************************************************/
 
#include "driverlib.h"
 
#define GPIO_PIN_ALL (GPIO_PIN0 | GPIO_PIN1 | GPIO_PIN2 | GPIO_PIN3 |          \
                      GPIO_PIN4 | GPIO_PIN5 | GPIO_PIN6 | GPIO_PIN7)
 
int main(void) {
 
    WDT_hold(WDT_BASE);
 
    // Configure GPIO for low current numbers while in LPM4.5
    GPIO_setOutputLowOnPin(GPIO_PORT_P1, GPIO_PIN_ALL);
    GPIO_setAsOutputPin(GPIO_PORT_P1, GPIO_PIN_ALL);
    GPIO_setOutputLowOnPin(GPIO_PORT_P2, GPIO_PIN_ALL);
    GPIO_setAsOutputPin(GPIO_PORT_P2, GPIO_PIN_ALL);
 
    // Determine if coming out of LPM 4.5
    if(PMM_getInterruptStatus(PMM_LPM45_INTERRUPT)) {
 
        PMM_clearInterrupt(PMM_LPM45_INTERRUPT);
 
        // Need to unlock IO after exiting LPM4.5 so LED will blink
        PMM_unlockIOConfiguration();
 
    } else {
 
        // Configure exit of LPM4.5 on P2.1 interrupt
        GPIO_setAsInputPin(GPIO_PORT_P2, GPIO_PIN1);
        GPIO_selectInterruptEdge(GPIO_PORT_P2, GPIO_PIN1,
                                 GPIO_LOW_TO_HIGH_TRANSITION);
        GPIO_clearInterrupt(GPIO_PORT_P2, GPIO_PIN1);
        GPIO_enableInterrupt(GPIO_PORT_P2, GPIO_PIN1);
 
        // Turn on LED to indicate we are about to enter LPM4.5
        GPIO_setOutputHighOnPin(GPIO_PORT_P1, GPIO_PIN4);
 
        // Turn off regulator so we can enter LPM4.5
        PMM_setRegulatorStatus(PMM_REGULATOR_OFF);
 
        __bis_SR_register(LPM4_bits);
    }
 
    // Slow down clock so we can see LED blink
    // Configure MCLK = ~1MHz
    CS_initClockSignal(CS_MCLK, CS_CLOCK_DIVIDER_16);
 
    while(1) {
        GPIO_toggleOutputOnPin(GPIO_PORT_P1, GPIO_PIN4);
        __delay_cycles(100000);
    }
}