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How to stop the 32KHz RTC of TPS659038

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Intellectual 1735 points

Hi,

In the datasheet of TPS659038, it says that the RTC can be stopped by software by clearing the STOP_RTC bit of the control register. When "0" is written to this bit, then read the RUN bit of status register to make sure the RTC is frozen. But there is still a 32K output at pin M11(CLK32KGO). Could you kindly help to look at it?

Any comments will be appreciate.

  • 0
    TI__Genius 16410 points

    Hello Terry,

    The STOP_RTC bit only stops the RTC from counting, so the current time (and registers) will no longer update. The clock is still active, as you have noticed.

    The power sequencer is the only way to enable/disable the CLK32KGO output, so it cannot be controlled by I2C. What is the reason that they need it stopped? If they want to slow down the edges, the can add a 10k resistor to ground. If it's about power, I'm afraid there's no way to disable it, though the increased quiescent current due to just the clock should be very small.

    I'm assuming your customer is using OTP 0x87. In case they would switch to 0x85 or 0x89, both of those OTPs have CLK32KGO disabled during operation (since crystal oscillator is bypassed).

    Regards,
    Karl

  • 0 in reply to Karl Wallinger
    TI__Intellectual 1735 points

    Dear Karl,

    Thank you very much for your kindly help !

    Regards,

    Terry