CCS/MSP430FR5889: RTC_C ALARM ISSUE

Vijeth K Shastry

Part Number: MSP430FR5889
Other Parts Discussed in Thread: MSP430FR5994

Tool/software: Code Composer Studio

Dear Team ,

We are using MSP430FR5994 Launch pad to examine the RTC_C Alarm module. Please find the configuration of RTC registers below. Alarm interrupt is not occurring. only the Event interrupt is occurring at every minute. RTC time registers are updating properly. I have gone through the errata sheet also. Not mentioned anything on this.

RTCCTL0 = RTCKEY ;

RTCCTL1 |= RTCMODE + RTCSSEL_0 ;

RTCCTL3 = 0x00;

RTCAMIN = 0x00;
RTCAHOUR = 0x00;
RTCADOW = 0x00;
RTCADAY = 0x00;
RTCCTL0_L = 0x00 ;

RTCAMIN = 0x02 ; // Alarm every 2 minutes

RTCCTL0_L = RTCRDYIE + RTCAIE ; // Enable alarm interrupt

RTCCTL0_L &= ~RTCTEVIFG; // disable the event interrupt flag;

RTCCTL1 &= ~ RTCHOLD ; // Release RTC for the operation

#pragma vector=RTC_VECTOR
__interrupt void RTC_ISR()
{
if(RTCCTL0_L & RTCRDYIFG)
{
RTCCTL0_L &= ~RTCRDYIFG;

if(strRtcFlags.bWriteToRtc)
{
strRtcFlags.bWriteToRtc =0;
RTCSEC = strRtcWrite.ucSecs;
RTCMIN = strRtcWrite.ucMins;
RTCHOUR = strRtcWrite.ucHours;
RTCDAY = strRtcWrite.ucDate;
RTCMON = strRtcWrite.ucMonth;
RTCYEAR = ((unsigned int)strRtcWrite.ucYear + 2000 );
}
strRtcRead.ucSecs = strMainParam.strTime2.ucSec = RTCSEC;
strRtcRead.ucMins = strMainParam.strTime2.ucMin = RTCMIN;
strRtcRead.ucHours = strMainParam.strTime2.ucHrs = RTCHOUR;
strRtcRead.ucDate = strMainParam.strTime2.ucDate = RTCDAY;
strRtcRead.ucMonth = strMainParam.strTime2.ucMonth = RTCMON;
strRtcRead.ucYear = strMainParam.strTime2.ucYear = (unsigned char)(RTCYEAR-2000);
}

if(RTCCTL0_L & RTCAIFG)
RTCCTL0_L &= ~ RTCAIFG;

if(RTCCTL0_L & RTCTEVIFG)
RTCCTL0_L &= ~RTCTEVIFG;

}

Thanks & Regards,

Century

over 7 years ago

0 Ryan Brown1 over 7 years ago

TI__Guru**** 202106 points

Hi Vijeth,

Please set the AE bit of the RTCAMIN register. I would also recommend reading Section 23.2.3 of the User's Guide.

Regards,
Ryan

0 Vijeth K Shastry over 7 years ago in reply to Ryan Brown1

Intellectual 485 points

Dear Ryan,

Sorry i had not copied that line of code.

But i have already set that bit. Here is the edited code. I have already gone through the user guide section for RTC_C. Still only the event interrupt is occurring even though it is not enabled.

/*********** Init RTC Registers **********************************************/

RTCCTL0 = RTCKEY ; // unlock the RTC registers
RTCCTL1 |= RTCMODE + RTCSSEL_0 ; // select RTC mode and LF xtal as source

RTCCTL3 = 0x00;
RTCAMIN = 0x00;
RTCAHOUR = 0x00;
RTCADOW = 0x00;
RTCADAY = 0x00;
RTCCTL0_L = 0x00 ;

RTCAMIN = 0x02 ; // Alarm every 2 minutes

RTCAMIN |= RTCAE; // Enable the minutes alarm bit

RTCCTL0_L = RTCRDYIE + RTCAIE ; // Enable alarm interrupt

RTCCTL0_L &= ~RTCTEVIFG; // disable the event interrupt flag;

RTCCTL1 &= ~ RTCHOLD ; // Release RTC for the operation

/************************ End of Initializing RTC Registers *****************************************/

/*************** Interrupt handler for RTC_C *****************************************************/

#pragma vector=RTC_VECTOR
__interrupt void RTC_ISR()
{
if(RTCCTL0_L & RTCRDYIFG)
{
RTCCTL0_L &= ~RTCRDYIFG;

}

if(RTCCTL0_L & RTCAIFG)
RTCCTL0_L &= ~ RTCAIFG;

if(RTCCTL0_L & RTCTEVIFG)
RTCCTL0_L &= ~RTCTEVIFG;

}

/*************** End of interrupt handler *******************************/

0 Ryan Brown1 over 7 years ago in reply to Vijeth K Shastry

TI__Guru**** 202106 points

Here is an example of an alarm interrupt occuring at every hour 2 minutes past the hour (12:02:00, 1:02:00, 2:02:00, etc.):

#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 = RTCAIE;    					// enable RTC alarm interrupt

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

    RTCYEAR = 0x2017;                       // Year = 0x2017
    RTCMON = 0x1;                           // Month = 0x01 = January
    RTCDAY = 0x18;                          // Day = 0x18 = 24th
    RTCDOW = 0x02;                          // Day of week = 0x02 = Tuesday
    RTCHOUR = 0x10;                         // Hour = 0x10
    RTCMIN = 0x01;                          // Minute = 0x01
    RTCSEC = 0x45;                          // Seconds = 0x45

    RTCAMIN = 0x02 | RTCAE;                 // RTC Minute Alarm
    RTCAHOUR = 0x00;
    RTCADOW = 0x00;
    RTCADAY = 0x00;

    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: break;       // RTCRDYIFG
        case RTCIV__RTCTEVIFG: break;       // RTCEVIFG
        case RTCIV__RTCAIFG:				// RTCAIFG
            __no_operation();               // Interrupts every xx:02:00 - SET BREAKPOINT HERE
            break;
        case RTCIV__RT0PSIFG:  break;       // RT0PSIFG
        case RTCIV__RT1PSIFG:  break;       // RT1PSIFG
        default: break;
    }
}

Regards, Ryan

**Attention** This is a public forum

MSP low-power microcontrollers

MSP low-power microcontroller forum

CCS/MSP430FR5889: RTC_C ALARM ISSUE