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MSP430FE427A: ESP430CE1A datasheet understanding issue.

Subhronil Chaudhuri
Intellectual 560 points
Part Number: MSP430FE427A

Hello there,

I am using the MSP430FE427a, it has a sub-processor; ESP430CE1A. The datasheet of this ESP430 talks about the sampling rate on page 11. I am having hard time understanding the whole paragraph(attached as an image below). I don't understand the statement "The number of samples for a complete ESP430 calculation sequence is 4096." , and " The sampling period is divided into 256 units to get the time base unit for the ESP430. " . 

I would really appreacite someone explaining this to me in the most dumbed-down manner.

Thanks in advance.

  • 0
    TI__Guru**** 202216 points
    Hello Subhronil,

    Assuming that the oversampling rate (SD16OSRx) is 256 then 4096 samples are required for a 16-bit sigma-delta value. The time required for each of these samples is equivalent to the inverse of the ADC sampling rate multiplied by the oversampling rate, resulting in the total measurement times given in Table 1-5. The ADC sampling frequency fADC is not to be confused with the number of samples required for a full conversion, which both happen to be 4069 in this example and therefore cancel each other out for a measurement time of 1 second. Slower sampling rates result in longer measurement times.

    Regards,
    Ryan
  • 0 in reply to Ryan Brown1
    Intellectual 560 points
    Hello Ryan,

    Thanks a lot for your answer it clarifies a lot. Now is it possible to change the " oversampling rate (SD16OSRx)" ? Cause, I am trying to reduce the measurement time, while keeping the same accuracy.

    If you have any suggestions, would be much appreciated.

    Thanks in advance.

    Regards
    Subhronil
  • 0 in reply to Subhronil Chaudhuri
    TI__Guru**** 202216 points
    Hi Subhronil,

    This is accomplished through the SD16OSRx bits of the SD16CCTLx register.

    Regards,
    Ryan

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