pmm_ex2_vmon1160mV.c

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/*******************************************************************************
 * MSP430i2xx Power Management Module - Voltage Monitor 1160mV
 *
 * Description: In this example, the device is setup to compare the VMONIN pin
 * to 1160mV. When the VMONIN pin drops below 1160mV the VMON interrupt fires
 * and the ISR is run. The voltage monitor interrupt flag is not clearable
 * by software and will only stop interrupting if VMON interrupt is disabled
 * or VMONIN goes above 1160mV. The LED is turned off when the voltage monitor
 * pin is below 1160mV and turns on when it is above. You can also use the
 * voltage monitor to monitor DVCC.
 *
 *
 *                MSP430i2041
 *             ------------------
 *         /|\|                  |
 *          | |              P1.4|-->LED
 *          --|RST               |
 *            |                  |
 *            |                  |
 *            |              P2.3|<--VMONIN
 *            |                  |
 *            |                  |
 *
 * Author: Zack Lalanne
 ******************************************************************************/
 
#include "driverlib.h"
 
int main(void) {
 
    WDT_hold(WDT_BASE);
 
    // Setup the LED
    GPIO_setOutputLowOnPin(GPIO_PORT_P1, GPIO_PIN4);
    GPIO_setAsOutputPin(GPIO_PORT_P1, GPIO_PIN4);
 
    // Setup the voltage monitor to compare VMONIN to 1160mV
    PMM_setupVoltageMonitor(PMM_VMONIN_1160MV);
 
    // When started up, VMON requires a settling time of 0.5us
    // MCLK = ~16MHz; 1 cycle = ~0.0625us
    __delay_cycles(10);
 
    // Setup VMONIN Pin
    GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P2,
                                               GPIO_PIN3,
                                               GPIO_TERNARY_MODULE_FUNCTION);
 
    // Enable the voltage monitor interrupt
    PMM_enableInterrupt(PMM_VMON_INTERRUPT);
    __bis_SR_register(GIE);
#if defined(__GNUC__)
    // Not necessary in Rev. D silicon, but appeases a warning for GCC
    __asm(" nop");
#endif
 
    while(1) {
        // If we are not in ISR then VMONIN > 1160mV
        GPIO_setOutputHighOnPin(GPIO_PORT_P1, GPIO_PIN4);
    }
}
 
 
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=VMON_VECTOR
__interrupt
#elif defined(__GNUC__)
__attribute__((interrupt(VMON_VECTOR)))
#endif
void VMON_ISR(void) {
    // VMONIN < 1160mV, LED Off
    GPIO_setOutputLowOnPin(GPIO_PORT_P1, GPIO_PIN4);
}