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msp430 clock frequencies

GURU MOORTHY
Expert 2425 points

Other Parts Discussed in Thread: MSP430G2553

what are the frequencies of mclk, smclk, vlo, aclk accurately, approximated to 4 decimal places?

  • 0
    Guru 46710 points

    GURU MOORTHY said:
    what are the frequencies of mclk, smclk, vlo, aclk accurately, approximated to 4 decimal places?

    Nobody can tell. It depends on actual clock source used. Mclk, smclk, vlo, aclk can be virtually ANY frequency as long as it is within supported range.

    Why you ask?

  • 0 in reply to Ilmars
    Guru 25210 points

    Ilmars said:
    Why you ask?

    I think he meant to post these questions to the "College Homework Answers Forum"

  • 0
    Guru 227245 points

    GURU MOORTHY said:
    what are the frequencies of mclk, smclk, vlo, aclk accurately, approximated to 4 decimal places?

    MCLK, SMCLK and ACLK frequency is what you configured it to be. See the clock system chapter of the users guide. The default configuration is also found in the users guide and the resulting frequency range (which differs across devices) is found in the device datasheet. The VLO frequency range is also found in the device datasheet.

    Since all these values are given as ranges, 4 decimal places are nonsense.

    If you run one of them (except VLO, fo course) from an external crystal, the crystal defines the frequency and precision.

    In any case, there is no single 'the frequency' answer. Except "it depends".

  • 0 in reply to Brian Boorman
    Expert 2425 points

    i want these for calculation for exact delays

  • 0 in reply to GURU MOORTHY
    Expert 2425 points

    they say vlo is of approximately 12000hz, but it is not the accurate value.

    they say smclk/mclk is 1MHz, but is not accurately.

    they say aclk is 32000hz, but is 32768hz.

    so i want values of vlo & smclk in msp430g2553.

  • 0 in reply to GURU MOORTHY
    Guru 46710 points

    VLO frequency and DCO calibration values and their tolerances are specified in the datasheet. You can find datasheet in the product page: http://www.ti.com/product/msp430g2553

    For example VLO specification. As you see there's no such thing as exact frequency for VLO:

  • 0 in reply to GURU MOORTHY
    Guru 227245 points

    GURU MOORTHY said:
    they say smclk/mclk is 1MHz, but is not accurately.
    they say aclk is 32000hz, but is 32768hz.
    so i want values of vlo & smclk in msp430g2553.

    You still didn't read or at least didn't understand the clock chapter of the users guide.

    VLO is (according to datasheet) 4 to 20 MHz. Likely in the range of 12MHz, but individual devices my stray towards 4 or 20Mhz.

    ACLK is what you feed it. Either VLO frequency or XT1 frequency (the default). If XT1 isn't there, then it is 0Hz by default.

    SMCLK as well as MCLK are set to DCO by default. And DCO default settings result in a frequency somewhere in the 1MHz range. However, only an external crystal or an individual calibration of the DCO gives more (crystal) or less (DCO) accurate frequencies.

  • 0 in reply to GURU MOORTHY
    Guru 25210 points

    GURU MOORTHY said:
    they say vlo is of approximately 12000hz, but it is not the accurate value.

    The datasheet accurately says that the frequency is 12Khz (typical) but can range anywhere from 4Khz to 20 Khz.

    GURU MOORTHY said:
    so i want values of vlo & smclk in msp430g2553.

    Go buy yourself a crystal of an appropriate frequency and connect it to your MSP. Then you will know what the clocks are.

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