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AM4376: Count-up timing after the RTC second register is cleared

UNA
Mastermind 7980 points

Part Number: AM4376

Hi,

Make sure that RTCSS_STS_REG.RUN = 0 (Frozen) and then Clear RTCSS_SECONDS_REG.
Then change to RTCSS_STS_REG.RUN = 1(Run), after 15us RTCSS_SECONDS_REG will be counted up.

I want the RTCSS_SECONDS_REG to count up one second after I set RTCSS_STS_REG.RUN to 1.
How can this be achieved? Is there a register that counts less than a second?

Best Regards,
H.U

  • 0
    TI__Mastermind 30865 points

    I'll need to check on this and get back to you early next week. 

      Paul

  • 0
    TI__Mastermind 30865 points

    H.U.

    I can't find from where you are getting the procedure you mention.

    RTCSS_STS_REG.RUN is a ready only status bit, you cannot set it. 

    However, If I understand your intent, you are asking if the RTCSS_SECONDS_REG  will be updated 1 second after setting RTCSS_CTRL_REG.STOP_RTC, then the answer is yes, bit only the first time.   If the RTCSS is paused while running (RTCSS_CTRL_REG.STOP_RTC = 0) , then the whole timer is paused. It will  not reset the counter driving the SECONDS_REG. Therefore, once the RTC_SS is resumed (RTCSS_CTRL_REG.STOP_RTC = 1),  the timer will resume from the point paused.  For example:

    -        if the RTSS is paused at 12.3 seconds and then restarted, it will resume at 12.3 seconds. Simple pause/resume

    -        If the RTSS is paused at 12.3 seconds and then the SECONDS_REG is update to 30,  the RTSS then resumes from 30.3 seconds, it does not start from 30.0.

    The 15us (15s is a typo)  mentioned inn the RTCSS_STS_REG.BUSY is related to the update window mentioned in  14.4.3.5.5 Modifying the TC registers. 

    If this is not the answer you were looking, then please provide more detail.

      Paul 

  • 0 in reply to PaulM
    Mastermind 7980 points

    Hi Paul,

    Thank you for reply.

    Set RTCSS_STS_REG.RUN" is my mistake. As you pointed out, by setting RTCSS_CTRL_REG.STOP_RTC, the RTC Start the count.
    Also, I understand that clearing RTCSS_SECONDS_REG and then setting RTCSS_CTRL_REG.STOP_RTC will always count up after 1 second.

    Best Regards,
    H.U

  • 0 in reply to UNA
    TI__Mastermind 30865 points

    H.U.

    I have updated the answer above to clarify the scenario.

      Paul