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MSP430F5342: XT2BYPASS adn

user4735871
Intellectual 320 points
Part Number: MSP430F5342

Dear TI:

        First,

        Now I am doing some test on MSP430F5342.

        According to the slau208q, I am in doubt about something.

        UCSCTL6 Register

        

        It says that "and XT2 is not in bypass mode of operation". If I use the XT2BYPASS mode, for example,24MHz oscillator(not crystal), it seems that i can't use the XT2OFF according to the XT2OFF bit highlight.

        If I want to turn off the XT2 oscillator(not crystal) in the XT2BYPASS mode, how can I do?Can I use the XT2OFF = 1?

        If I want to turn on the XT2 oscillator(not crystal)  in the XT2BYPASS mode, can I use the XT2OFF = 0?

 

        Second

       

  • 0
    Intellectual 320 points

          If I use these bits to set the MCLK and SMCLK source, will the system automatically switch to the DCOCLKDIV when I turn off the XT2CLK?

          What should I do?If it can be done, how long it takes for the switch?

          THANKS!

          Best Regards!

  • 0 in reply to user4735871
    TI__Genius 9570 points

    Hi，

    You can find the details from the block diagram.

    Ling

  • 0 in reply to Ling Zhu2
    Intellectual 320 points

    Hi Ling，

    Thank you for your help.Now I know that XT2CLK will continuously turn on if XT2BYPASS mode has been used.

    However，I still have some question in detail.

    First，if XT2BYPASS mode has been used，according to slau208q，XT2 is powerd down.Does this mean XT2 is powerd by external

    TCXO independently？If I want to turn off XT2 to save power before going to LPM3，turning off the TCXO's power supply will take effect？

    Second，if I use XT2CLK as the source of MCLK and SMCLK，then turn off XT2CLK.How long will it take for the switch from XT2CLK to DCO？Is this 

    switch done automatically?If not，how can I swtich manually？

    Thanks

    Best Regards

  • 0 in reply to user4735871
    TI__Genius 9570 points

    1. Yes.

    2. Yes automatically, please refer to chapter 5.2.12 UCS Module Fail-Safe Operation

  • 0 in reply to Ling Zhu2
    Intellectual 320 points

    Hi Ling，

    Thanks a lot for your help.But I think the chapter you want me to refer to is 5.2.13，Synchronization of Clock Signals.

    Best Regards.

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