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LM4F232H5QD - RTC in case of power failure

Anand Kumar Rai
Intellectual 720 points

Hi folks!!

I am using LM4F232H5QD in one of the GPS based applications. I want my MCU to keep track of Real Time Clock even in case the power on VDD pin fails. I will be using CR2032 Li battery with 32.768 KHz external crystal oscillator. There is a VBAT in MCU, only connecting CR2032 battery with that pin and some codes will help or I need to go with some other option. Please help me for the implementation of this requirement.

Thanks in advance.

Thanks and Regards

-Anand Kumar Rai

  • 0
    TI__Mastermind 18905 points

    Anand,

    Sorry for the delayed response.  We recently made some changes in our E2E forums, and your post was missed in the process. 

    Your best  option for an example how to use RTC is in event of power loss, is to look at the two evaluation kits that we have that specifically demonstrate low power options.  If power to GPIO needs to be retained, then the LM4F120 LaunchPad board is designed to demonstrate the 3V3_On mode.  The EKK-LM4F232 demonstrates Vbat supplying the Hibernate module and the HIB output pin used to cut power to the rest of the components on the board including Vdd. 

    The evuation kits have software specific to demonstrating Hibernate example.  The software, board details, and schematics are all downloadable at:

    • scroll down to EKK-LM4F232 and click the get software button
    • scroll down to LM4F120 LaunchPad and click the get software button

    The schematics are in the User Guide, found in the Stellarisware/docs folder post downloading the software CD.  Please let me know if you have any additional questions.

    Lela 

  • 0 in reply to Lela Garofolo
    Intellectual 720 points

    Hi Lela,

    I am looking in to Evaluation board schematics and this answers my question.

    Thanks for your support!!!

    Thanks and Regards

    -Anand