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MSP430FR2311: Clock Frequency Calibration and Trimming

Dan Cristy
Intellectual 2615 points

Part Number: MSP430FR2311

Hi Team –

Posting on customer behalf.

We are using the MSP430FR2311 16 Bit configuration….

 

I have a couple of questions about the Clock Frequency calibration and trimming.

 

1.       What is the tolerance on the clock frequency when I am using a 16MHz clock? I see in the users manual that I wouldn’t really be needing a software trim function if I am running within a certain range of frequencies. My understanding is that 16MHz is in that range of frequencies.

2.       Do I need to be doing anything on my end for using the factory calibration value? If I set the DCOFTRIMEN to 0 , would that be enough for the clock to use the DCOFTRIM value during factory calibration?

3.       I see that the clock is off, and running slow. So, I had to use the Software trim on my demo board for my modules to work right. Any suggestions to minimize the error?

 

Thank you,

Dan

  • 0
    Intellectual 510 points
    You can use the FLL, it will set the multipliers so the DCO is running at a specified frequency.
    The selection of ranges guarantee the FLL can reach those frequencies, but you still need to run the FLL or manually select all values for each microcontroller.

    User guide, section 3.2.5 and 3.2.6 explain a little.
  • 0
    TI__Guru**** 222477 points
    Hi Dan,

    1. This is provided for a variety of sources and temperature ranges on Table 5-5 of the Datasheet.
    2. Refer to code examples msp430fr211x_CS_[03/05].c, DCOFTRIM is chip-specific trimmed and should not need to be altered.
    3. This depends on the FLL reference, XT1 crystal will minimize error but REFO will allow some error. How slow is the clock running as compared to expected? DCO software trim should be performed according to the process in Section 3.2.11.2 of the User's Guide.

    Regards,
    Ryan

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