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MSP430F2491 : XIN, XOUT External Crystal Power Output Method Inquiry

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Replies: 4

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Part Number: MSP430F2491

I am trying to change the chipset of the system using the MSP430F149.
We are reviewing the MSP430 series, which is judged to be a reasonably similar chipset.
There is a strange problem during H / W configuration.

The original system uses an external clock of 3.6864MHz.
The MSP430F149 has a 3.3V output on the XOUT pin when powered on.
Therefore, the external crystal vibrates.

However, the MSP430F2491, MSP430F2619, and MSP430F417 output only about 500 mV when the power is turned on.
Crystal oscillation does not work ...

How can I get 3.3v output from the XIN and XOUT pins?

Do you need software configuration?
Do you need hardware configuration?

Is there a document to reference?
Is there any code to reference?

  • A miss was found. I want to change my MSP430F149 system to another chipset.
  • Hi,

    Let me quickly clarify your question:

    1) You want to switch your MCU from MSP430F149 to MSP430F2491.

    2) You're unsure if the HF oscillator works.

    First of all I would advise to not compare the XOUT voltages accross different MCU families, they may not be the right indicator for proper oscillator functionality.

    I'll therefor focus on different tips and tricks when handling oscillators to troubleshoot your issue.

    As a starting point I'd advise you to have a look at the MSP430 32-kHz Crystal Oscillators Application report, which, regardless of the title, also applies to high frequency oscillators and thus adresses your topology, too. Please thoroughly check layout and load capacitance considerations as those items are very crucial to proper oscillator functionality.

    Second, this application report also advises on how to properly measure crystal operation.

    In order to measure the operation and frequency of the external oscillator, I'd advise you to adjust your clock settings to source the internal SMCLK from the external crystal and then route the SMCLK signal to an external pin which you can monitor using an oscilloscope without affecting the external crystal. To make sure the internal connections are fine, you can first source the SMCLK from the internal DCO and check if you are able to measure the DCO frequency at the external pin. Then try again sourcing SMCLK from the external crystal.

    Also make sure that you have the right regiter settings in the Basic Clock System Control Register 1 and 3. Please check the MSP430x2xx Family User's Guide Section 5.3.2 and 5.3.4 and set XTS= 1 (LFXT1 in high-frequency mode) and LFXT1Sx according to your external crystal.

    Please come back to me after you've conducted the tests and had a look into documentation so that we can go on troubleshooting your issue (in case it still exists).

    Thanks and best regards,

    Britta

  • In reply to Britta Ruelander:

    Hi,

    have you been able to solve your issue?
    Please let me know if you need further assistance and if the issue persists.
    Otherwise let me know that I can go ahead and close this thread after you've verified the answer.
    Thanks and best regards,
    Britta
  • In reply to Britta Ruelander:

    Hi,

    please note that I will go ahead and close this thread as I didn't hear back from you.
    If you need further assistance note that replying to this thread will re-open it.

    Best regards,
    Britta

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