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MSP430FR6047: Clock source accuracy for USS measurement

Genius 16545 points
Part Number: MSP430FR6047

Tool/software:

Hello,

My customer has a question for MSP430FR6047 USS soluction, especially for clock source accuracy.

They selected a 8MHz ceramic resonator as the clock souce of FR6047 for ultrasonic measurement.
They want to understand how the difference in the accuracy of the clock source affects the ultrasonic measurement.

For example, if the clock source accuracy is different by xx%, can the propagation time of the output of the microcontroller be different by the same xx%?
They want to clarify the acceptable range of the clock source accuracy to meet the expected flow accuracy.

Regards,
Oba

  • Hi Oba,

    Changing the clock source to something with a different accuracy could change the measurement accuracy by a similar %. It will likely not be exactly the same considering the number of confounding factors here: The clock will control how we send the pulses, how we read them back with the ADC, the internal timers, and then we feed all of the data into the USS algorithm.

    My recommendation would be to utilize the same oscillator used in our EVM and the reference design to avoid issues. This can be found in the BOM which is listed on the EVM Product Page.

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