wdt_ex2_watchdogMode.c

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/*******************************************************************************
 * MSP430i2xx Watchdog Timer - Watchdog Mode
 *
 * Description: In this example, the Watchdog Timer is setup in watchdog mode
 * using SMCLK as a source. SMCLK is configured as the DCO / 16 and the WDT
 * is configured as SMCLK / 32768 resulting in a Watchdog period of 32ms. The
 * LED is turned on when entering LPM and turned off once the device has been
 * reset by the WDT. After reset the device checks to make sure it was the
 * WDT that caused the interrupt and turns off the LED.
 *
 *
 *                MSP430i2041
 *             ------------------
 *         /|\|                  |
 *          | |                  |
 *          --|RST               |
 *            |              P1.4|-->LED
 *            |                  |
 *            |                  |
 *            |                  |
 *            |                  |
 *
 * Author: Zack Lalanne
 ******************************************************************************/
 
#include "driverlib.h"
 
int main(void) {
 
    // Stop the WDT
    WDT_hold(WDT_BASE);
 
    // Check if WDT caused reset
    if(SFR_getInterruptStatus(SFR_WATCHDOG_INTERRUPT)) {
        SFR_clearInterrupt(SFR_WATCHDOG_INTERRUPT);
        GPIO_setOutputLowOnPin(GPIO_PORT_P1, GPIO_PIN4);
    }
 
    GPIO_setAsOutputPin(GPIO_PORT_P1, GPIO_PIN4);
 
    // Setup DCO to use internal resistor. DCO calibrated at 16.384 MHz
    CS_setupDCO(CS_INTERNAL_RESISTOR);
 
    // Setup SMCLK as DCO / 16 = 1.024 MHz
    CS_initClockSignal(CS_SMCLK, CS_CLOCK_DIVIDER_16);
 
    // Configure interval to SMCLK / 32768 = 32ms
    WDT_initWatchdogTimer(WDT_BASE,
                          WDT_CLOCKSOURCE_SMCLK,
                          WDT_CLOCKDIVIDER_32K);
    WDT_resetTimer(WDT_BASE);
 
    GPIO_setOutputHighOnPin(GPIO_PORT_P1, GPIO_PIN4);
 
    // Start the WDT and enter LPM0
    WDT_start(WDT_BASE);
    __bis_SR_register(LPM0_bits);
}