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Oscillator calibration

Dan S17
Expert 1510 points
Other Parts Discussed in Thread: TMS570LS0432

Hello e2e

What is a good method to calibrate the main oscillator used on the Hercules board?


Thank you!

  • 0
    TI__Genius 11645 points

    Dan,

    One of our experts will get back to you on this.

    In the meanwhile we do use the external crystal oscillators on our launch pad's, so we would like to know little more detail on what you are intending to.

  • 0 in reply to KARTHIKEYAN RAJAMANICKAM
    TI__Genius 11645 points

    Dan,

    Have you had a look at the DCC module available in TMS570LS0432.

    http://www.ti.com/lit/ug/spnu517a/spnu517a.pdf

    Please refer section-10 (DCC) which will help you understand on how to measure the external clock using other clock sources which can also be internal to the device. This can be used in different ways without CPU spending bandwidth on it.

    Hope that helps.

  • 0
    TI__Mastermind 49120 points

    Dan,

    The main oscillator on the board is expected to be (and assumed to be) the most accurate clock reference available. This is mainly due to the fact that the oscillator vendor will have verified and ensured the specified start-up time and frequency characteristics of the oscillator. As a rule, the MCU datasheet requires users to submit their board design to the oscillator vendor for this characterization purpose.

    There is a low-power oscillator (LPO) on-chip whose main purpose is to be used to check on the availability of the main oscillator signal (oscillator monitor). This LPO is not meant to be used for actual calibration of the main oscillator.

    You do have one option though - drive in an accurate clock signal on one of the available EXTCLKINx inputs. Then you can use the Dual-Clock Comparator (DCC) module to measure the main oscillator frequency using the EXTCLKIN as the reference.

    Regards, Sunil