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MSP430FR5994: suitable HFXT selection

Joakim
Intellectual 1950 points

Part Number: MSP430FR5994
Other Parts Discussed in Thread: MSP430F149



Please help me with the selection of a suitable crystal (HFXT).

I would like to use as high frequency as possible, per datasheet this is 24Mhz.

Requirements:

-       The UART has to be able to communicate at 2400, 4800, 9600, 19200, 38400, 56 kbps

-       Operating conditions: -40 … +60C

Please advise if there is an application note that can guide me in the right direction in the selection of the best crystal/resonator/oscillator -solution (unless you can answer directly).

Thanks

  • 0
    TI__Genius 14930 points

    Hello,

    Crystal selection is typically guided by the customer's application and requirements. An application that requires precise timing would require a crystal with a small ppm variation. If the application is more lenient on timing then a lower cost crystal can be used with larger ppm variation. The same concept applies for temperature ranges, speed, etc.

    Information on all of these parameters can be found in the specific crystal's datasheet.

    There is an application report named MSP430™ 32-kHz Crystal Oscillators which gives insight into factors that go into crystal selection, layout tips, and many other considerations. The general ideas apply to high frequency crystals in addition to the 32-kHz crystal noted in the title.

    For specific recommendations, you can find reference designs or TI Designs which use our device with a high frequency crystal and see which specific crystal that reference design uses.

    Best regards,

    Matt

  • 0 in reply to Matt Calvo
    TI__Intellectual 1950 points

    Thank you!

    This was very useful information. I woild like to correct the speed requirement I mentioned before, 56kbps should be 57,6kbps In case someone wondered.

    Also please let me know if you have the system frequency vs Supply voltage graphs available for the FR5994, like you have on the MSP430F149 (Datasheet; page: 17) and F5342 (Datasheet; page :12) ?

  • 0 in reply to Joakim
    TI__Genius 14930 points
    The system frequency vs supply voltage graphs only apply to our flash based devices. For FRAM devices, the attainable system frequency is not a function of supply voltage.

    Best regards,

    Matt
  • 0 in reply to Matt Calvo
    TI__Intellectual 1950 points
    That's explains it yes. Thanks for the support

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