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MSP430f4xx and Dco

omeraygor
Intellectual 410 points


Hi

Are you suggesting using MSP430f4xx devices with DCO module and without using any externel crystal? 

can uart module and other modules work with DCO?

can Dco adjustable desired frequency without crystal? 

Thanks...

  • 0
    TI__Mastermind 24390 points

    The DCO can be used with no external crystals attached. The FLL module is enabled by default on reset, but it can be disabled and the DCO can be configured manually to a frequency according to the settings in the device datasheet. See also section 5.2.5 of the 4xx User's Guide 

  • 0 in reply to Brandon08
    Intellectual 410 points

    hi Brandon

    the document that you suggest(4xx User's Guide) is giving only frequency range. 

    For example.

    i want to produce 700kHz from DCO. 

    *disabled FLL module.

    *FN_8 FN_4 FN_3 FN_2 = 0 0.65 to 6.1

    it is in this range but not exactly frequency i expected.

    is there any formula for DCO freq.?

    thanks...

     

     

  • 0 in reply to omeraygor
    TI__Mastermind 24390 points

     

    omeraygor,

    Many factors affect the DCO frequency for a certain DCO register setting. These include device supply voltage and temperature. 

    Because of this, only frequency ranges are specified for DCO register settings so a specific frequency needs to be determined experimentally. 

    The settings required for a given frequency may vary from device to device. 

     

    Page 42 of the MSP430FG4619 Device Datasheet shows the range of frequencies that can be acheived with different DCO register settings and can give you a good starting point for before experimentation. Please also note page 43 as well. 

     

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