CCS/MSP430FR5994: How to set up the alarm in RTC module

Hi Senith,

Thanks for using MSP decive.

You could take the code example for RTC_C as reference, which demonstrates the RTC mode by triggering an interrupt every second and minute.

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//******************************************************************************
//  MSP430FR5x9x Demo - RTC in real time clock mode
//
//  Description: This program demonstrates the RTC mode by triggering an
//  interrupt every second and minute. This code toggles P1.0 every second.
//  This code recommends an external LFXT crystal for RTC accuracy.
//  ACLK = LFXT = 32768Hz, MCLK = SMCLK = default DCO = 1MHz
//
//                MSP430FR5994
//             -----------------
//        /|\ |              XIN|-
//         |  |                 | 32768Hz
//         ---|RST          XOUT|-
//            |                 |
//            |            P1.0 |--> Toggles every second
//            |                 |
//
//   William Goh
//   Texas Instruments Inc.
//   October 2015
//   Built with IAR Embedded Workbench V6.30 & Code Composer Studio V6.1
//******************************************************************************

#include <msp430.h>

int main(void)
{
    WDTCTL = WDTPW | WDTHOLD;               // Stop Watchdog Timer

    P1DIR |= BIT0;                          // Set P1.0 as output

    PJSEL0 = BIT4 | BIT5;                   // Initialize LFXT pins

    // Disable the GPIO power-on default high-impedance mode to activate
    // previously configured port settings
    PM5CTL0 &= ~LOCKLPM5;

    // Configure LFXT 32kHz crystal
    CSCTL0_H = CSKEY_H;                     // Unlock CS registers
    CSCTL4 &= ~LFXTOFF;                     // Enable LFXT
    do
    {
      CSCTL5 &= ~LFXTOFFG;                  // Clear LFXT fault flag
      SFRIFG1 &= ~OFIFG;
    } while (SFRIFG1 & OFIFG);              // Test oscillator fault flag
    CSCTL0_H = 0;                           // Lock CS registers

    // Configure RTC_C
    RTCCTL0_H = RTCKEY_H;                   // Unlock RTC
    RTCCTL0_L = RTCTEVIE_L | RTCRDYIE_L;    // enable RTC read ready interrupt
                                            // enable RTC time event interrupt

    RTCCTL13 = RTCBCD | RTCHOLD | RTCMODE;  // RTC enable, BCD mode, RTC hold

    RTCYEAR = 0x2010;                       // Year = 0x2010
    RTCMON = 0x4;                           // Month = 0x04 = April
    RTCDAY = 0x05;                          // Day = 0x05 = 5th
    RTCDOW = 0x01;                          // Day of week = 0x01 = Monday
    RTCHOUR = 0x10;                         // Hour = 0x10
    RTCMIN = 0x32;                          // Minute = 0x32
    RTCSEC = 0x45;                          // Seconds = 0x45

    RTCADOWDAY = 0x2;                       // RTC Day of week alarm = 0x2
    RTCADAY = 0x20;                         // RTC Day Alarm = 0x20
    RTCAHOUR = 0x10;                        // RTC Hour Alarm
    RTCAMIN = 0x23;                         // RTC Minute Alarm

    RTCCTL13 &= ~(RTCHOLD);                 // Start RTC

    __bis_SR_register(LPM3_bits | GIE);     // Enter LPM3 mode w/ interrupts enabled
    __no_operation();

    return 0;
}

#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=RTC_C_VECTOR
__interrupt void RTC_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(RTC_C_VECTOR))) RTC_ISR (void)
#else
#error Compiler not supported!
#endif
{
    switch(__even_in_range(RTCIV, RTCIV__RT1PSIFG))
    {
        case RTCIV__NONE:      break;       // No interrupts
        case RTCIV__RTCOFIFG:  break;       // RTCOFIFG
        case RTCIV__RTCRDYIFG:              // RTCRDYIFG
            P1OUT ^= 0x01;                  // Toggles P1.0 every second
            break;
        case RTCIV__RTCTEVIFG:              // RTCEVIFG
            __no_operation();               // Interrupts every minute - SET BREAKPOINT HERE
            break;
        case RTCIV__RTCAIFG:   break;       // RTCAIFG
        case RTCIV__RT0PSIFG:  break;       // RT0PSIFG
        case RTCIV__RT1PSIFG:  break;       // RT1PSIFG
        default: break;
    }
}

Hi Jetim ,

Yeah I’ve gone through these example codes.. but these don’t explain how to set up the alarm interrupt.

I tired enabling RTCAIE and the RTCAMIN and RTCAHOUR, but still it didn’t trigger the interrupt at the time I set.

I’ll post the method I tried.

Hi Jetmi,

Sorry for the late reply,
I though I would get an email for every reply on this thread but only got an email for the 1st reply I got. So I didn't know there was new replies. My bad.

the method i tried was this,

#include <msp430.h>

int main(void)
{
    WDTCTL = WDTPW | WDTHOLD;               // Stop Watchdog Timer

    P1DIR |= BIT0 + BIT1;                          // Set P1.0 as output

    PJSEL0 = BIT4 | BIT5;                   // Initialize LFXT pins

    // Disable the GPIO power-on default high-impedance mode to activate
    // previously configured port settings
    PM5CTL0 &= ~LOCKLPM5;

    // Configure LFXT 32kHz crystal
    CSCTL0_H = CSKEY_H;                     // Unlock CS registers
    CSCTL4 &= ~LFXTOFF;                     // Enable LFXT
    do
    {
      CSCTL5 &= ~LFXTOFFG;                  // Clear LFXT fault flag
      SFRIFG1 &= ~OFIFG;
    } while (SFRIFG1 & OFIFG);              // Test oscillator fault flag
    CSCTL0_H = 0;                           // Lock CS registers

    // Configure RTC_C
    RTCCTL0_H = RTCKEY_H;                   // Unlock RTC
    RTCCTL0_L = RTCOFIE | RTCAIE | RTCRDYIE | RTCTEVIE;    // enable RTC read ready interrupt
                                            // enable RTC time event interrupt

    RTCCTL13 = RTCBCD | RTCHOLD | RTCMODE;  // RTC enable, BCD mode, RTC hold

    RTCYEAR = 0x2010;                       // Year = 0x2010
    RTCMON = 0x4;                           // Month = 0x04 = April
    RTCDAY = 0x05;                          // Day = 0x05 = 5th
    RTCDOW = 0x01;                          // Day of week = 0x01 = Monday
    RTCHOUR = 0x10;                         // Hour = 0x10
    RTCMIN = 0x32;                          // Minute = 0x32
    RTCSEC = 0x45;                          // Seconds = 0x45

    //RTCADOWDAY = 0x2;                       // RTC Day of week alarm = 0x2
    //RTCADAY = 0x20;                         // RTC Day Alarm = 0x20
    RTCAHOUR = 0b10001010;                        // RTC Hour Alarm. 1st bit made 1 to enable AE
    RTCAMIN =  0b10100011;                         // RTC Minute Alarm.  Same as above

    RTCCTL13 &= ~(RTCHOLD);                 // Start RTC

    __bis_SR_register(LPM3_bits | GIE);     // Enter LPM3 mode w/ interrupts enabled
    __no_operation();

    return 0;
}

#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=RTC_C_VECTOR
__interrupt void RTC_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(RTC_C_VECTOR))) RTC_ISR (void)
#else
#error Compiler not supported!
#endif
{
    switch(__even_in_range(RTCIV, RTCIV__RT1PSIFG))
    {
        case RTCIV__NONE:      break;       // No interrupts
        case RTCIV__RTCOFIFG:  break;       // RTCOFIFG
        case RTCIV__RTCRDYIFG:              // RTCRDYIFG
            P1OUT ^= 0x01;                  // Toggles P1.0 every second
            break;
        case RTCIV__RTCTEVIFG:              // RTCEVIFG
           // __no_operation();              // Interrupts every minute - SET BREAKPOINT HERE
            break;
        case RTCIV__RTCAIFG:
            P1OUT = 0x02;                   //Turn on p1.2 LED when alarm is triggered
            break;                           // RTCAIFG
        case RTCIV__RT0PSIFG:  break;       // RT0PSIFG
        case RTCIV__RT1PSIFG:  break;       // RT1PSIFG
        default: break;
    }
}

The above code is one of the sample codes provided. I then modified it to include the alarm function. Am I enabling the AE on wrong?

Thank you.

Hi Wei,

Sure thing...

Thank you