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  1. #1
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    how to measure crystal frequency

    now the CPU works well. when I try to measure the frequency with oscillagraph,
    I can not get the frequency. so why?
    The frequency is 12Mhz. And the load capacitor is 12pf.

    I can use the same setting of oscillagraph to measure the frequency of oscillator.

    •   Alt5th November 2008, 10:00

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  2. #2
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    how to measure crystals

    The CPU oscillation may be corrupted by the input capacitance and resistance of your oscilloscope.

    You can measure frequency of pulse at any output pin that relates firmly with CPU clock, it must be very convenient to do this in case your CPU is flash then you can write the seperate program for this purpose without wasting a CPU, or plug the crystal into any seperate oscillator to measure its frequency.



    •   Alt5th November 2008, 10:22

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  3. #3
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    measure crystal frequency

    thansks for your reply. I know that some CPU has the clock output pin. So we just test if crytsal works or not.

    but now i want to test the crystal frequency directly.
    I have selected the 10x attenuation probe. but I still can not measure the frequency. but the cpu works....



    •   Alt5th November 2008, 14:31

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  4. #4
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    how to measure frequency of a crystal

    Hi,

    Try to do what nguyennam explained or use a very low capacitive scope probe.
    I hope that helps.

    Samy



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