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Can MSP430F2132 work with internal crystal?

Xiaoguang Zhao2
Prodigy 50 points
Other Parts Discussed in Thread: MSP430F2132

Hi all,

I just start to work on a PCB design with MSP430F2132. I am not familiar with MSP430 MCUs. Because the space of the board should be small, so I want to make the  MSP430F2132 work without external crystal, only with the internal crystal. Is it possible? If it is, how can I connect the pins? Thank you very much.

Xiaoguang

  • 0
    Guru 25210 points

    It is possible, depending upon the clock accuracy requirements of your application. Make sure to look at the accuracy spec of the internal oscillator for your part and that it meets your needs, especially if you are implementing any communications protocols with it.

    As far as external connections, you can leave the XT1/XT2 pins unconnected, or connect them to digital I/O if they are multiplexed and you need the extra I/O. (I prefer to put surface-mount test point pads and leave unconnected to anything else as a "just-in-case").

    By default, the MSP will boot up using the internal oscillator anyway. Just set up the UCS as needed with the internal clock as the source.

    Good Luck!

  • 0
    Guru 227245 points

    none of the MSP430 processors has an internal crystal.
    All have an internal digitally controlled oscillator, which allows operation without an external crystal. However, DCO operation is subject to much larger tolerances than crystal opration. The same DCO setting results in largely different operating frequencies on different MSPs even of the same model. Some MSPs provide calibration information (DCO config settings determined at production time for one or more common frequencies such as 1MHz).
    Newer MSPs (5x/6x family) also offer a calibrated low-frequency reference oscillator (REFO) which can be use with the FLL feature to adjust the DCO at runtime towards a programmable multiple of the REFO frequency. The 2132, however, doesn't.

    On the 2132, if you don't use an external crystal, you can use the pins as digital I/O after clearing bit 6 and 7 in P2SEL register.

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