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Xtal values for 5438A

Varun Prasad
Prodigy 245 points

Other Parts Discussed in Thread: MSP430WARE

Hi,

We are using 5438A, in our design, and we want to clock our application at 25M Hz for which we need to connect external Xtal.

So what Xtal values and make do you suggest for accurate performance at 25MHz.

Thanks,

Varun

  • 0
    Guru 227245 points

    Pick a crystal that has the desired frequency and matches the requirements in the MSP datasheet (max oscillation allowance and max load capacitance).

    The attach it and add teh required load capacitance (see crystal datasheet).

  • 0 in reply to Jens-Michael Gross
    Prodigy 245 points

    "Pick a crystal that has desired frequency"

    You mean to clock at 25 Mhz, I can choose the same value (25 MHz)crystal, is that so?

  • 0 in reply to Varun Prasad
    Guru 227245 points

    Varun Prasad said:
    You mean to clock at 25 Mhz, I can choose the same value (25 MHz)crystal, is that so?

    Yes. A 25MHz baseband crystal (be sure to not get an overtone crystal - they tend to run on 1/3 frequency if conditions are less than perfect) with a maximum load capacitance of ~18pF.

    Pick the proper configuration 8driving strength etc.) in the MSP clock module registers, do the checking loop for the crystal coming up (found in almost every demo code) and switch MCLK over.

    Don't forget to raise core voltage before you clock a 5x device with more than 8MHz. (best use MSP430ware function for this job)

  • 0 in reply to Jens-Michael Gross
    Prodigy 245 points

    Hi Jens,

    Thank you, for the information. I have not yet gone through the full details for oscillator configuration, I needed this information for material procurement.

    Regards,

    Varun

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