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MSP430F5438A: About RTC backup.

user6181012
Prodigy 250 points

Part Number: MSP430F5438A

Hi

Please give me advice below.
I have a question about RTC operation on MSP430F5438A.
Let me confirm that only the RTC runs on the backup battery when the system power is off.
1.Is there a dedicated power terminal for RTC?
2.If not, how many volts does VCCC1 to 4 operate at RTC?

3.During RTC operation with a backup battery, the RESET pin is set to “L”.
Will this affect the RTC operation?

Does the RTC not operate with the RESET pin “L”?
Please tell us about the above.
Best regards
k.saito

  • 0
    TI__Genius 14930 points

    Hello,

    Just to get on the same page here, the battery backup RTC functionality is available on the RTC_B peripheral; however the MSP430F5438A contains only the RTC_A peripheral on board. Could you please look into this and let me know about your specific setup?

    Best regards,

    Matt

  • 0 in reply to Matt Calvo
    Prodigy 250 points

    Hi

    Thank you for your response.

    Let me check about RTC_A of MSP430F5438A.
    Q1.How many volts does RTC_A operate at the lower limit voltage?
    Q2.Does RTC_A stop operating when the RESET pin goes low?
    Q3.How many current when only RTC_A operates?

    Please answer three questions.
  • 0 in reply to user6181012
    TI__Genius 14930 points

    Hello,

    1) The RTC peripheral operates properly within the allowable voltage supply range of the device (1.8V - 3.6V)

    2) The Reset pin going low triggers a brownout reset (BOR) which then causes the RTC register values to switch back to their default reset values as given in the user's guide Section 22.3.

    3) Section 5.5 of the datasheet shows current consumption in different low power modes. You can refer to the LPM3 w/ VLO spec to get a rough estimate of the RTC current consumption. For example with a 3V supply at 25C and the device running in LPM3 with RTC enabled, the current consumption ranges from 1.2uA to 1.4uA.

    Best regards,

    Matt

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