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MSP432 RTC Count/Timer register

Aldabreu
Intellectual 2890 points

Good day,

I was wondering if there was a register not specified within the datasheet for the Real-Time Clock peripheral that holds the current count in seconds. After reading through the User's guide/datasheet it doesn't seem like there is one, but it would be helpful rather than converting the mm/dd/yr etc. And by seconds register I mean a register that would contain the UNIX epoch count.

Thank you for your time.

--Alexander

  • 0
    TI__Guru**** 221267 points
    Good day Alexander,

    When using the RTC in hexadecimal format the RTCSEC, RTCMIN, RTCHOUR, RTCDOW, RTCDAY, RTCMON, and RTCYEAR registers contain the decimal representation of the seconds, minutes, hours, day of week, day of month, month, and year, respectively. There is not, however, a register that keeps track of the UNIX epoch count, you would have to create a variable that stores that information manually.

    Regards,
    Ryan
  • 0 in reply to Ryan Brown1
    TI__Intellectual 2890 points

    Alright thankyou, just making sure.

    Best,

    --Alexander

  • 0 in reply to Ryan Brown1
    Expert 1450 points

    Hello Ryan,

    Is it possible to use the RTC for creating a time and a datestamp, because I want to put the values of the ADC on the UART with a time and a datestamp.?

    I tried to read out the values of the RTCSEC but the value was always the same.

  • 0
    Expert 1450 points

    Hi guys,

    I want to use the internal RTC for creating date- and timestamps, but when I set the parameters and start the RTC the values of the RTC Register (e.g. RTCMIN) didn't change.

    Could I use the RTC for my desired function? (the source code is mentioned below) 

    void RTCConfig(void)
{
		RTCYEAR = 2010;                         // Year = 0x2010
	    RTCMON = 4;                             // Month = 0x04 = April
	    RTCDAY = 5;                            // Day = 0x05 = 5th
	    RTCDOW = 1;                            // Day of week = 0x01 = Monday
	    RTCHOUR = 10;                           // Hour = 0x10
	    RTCMIN = 32;                            // Minute = 0x32
	    RTCSEC = 45;                            // Seconds = 0x45

	    RTCCTL1 &= ~(RTCHOLD);                    // Start RTC calendar mode
	    RTCCTL0_H = 0;                            // Lock the RTC registers
}

    Thanks.

  • 0 in reply to Christoph Marko
    TI__Guru**** 221267 points

    Hello Christoph,

    Yes it is possible, it is called RTC_C calendar mode and is covered in Chapter 18 of the MSP432P4xx Family Technical Reference Manual. Examples of this mode (msp432p401_rtc_01, rtc_c_calendar_alarm_interrupt.c) are provided in both C and driverlib format. Pay special attention as to whether you are operating in hexadecimal or BCD format as this changes the output values of the RTC registers. If the value of RTCSEC is always the same then the RTC has most likely not been initialized/started properly.  Usual cases involve not unlocking/holding the RTC before setting the timestamp registers or setting the timestamp registers to a nonsensical value for the given format.

    Regards,
    Ryan

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