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How to change AD5940's sampling frequency

I change BiaODR  value, but  the sampling frequency w does not change as this.So I would like to ask how to change the sampling frequency in the 4-wire BIA measurement, because I need a sampling frequency of 1000hz.thanks.

  • Hi,

      With the default AFE configuration, max allowed ODR is 10Hz. 

    For ODR more than this, ADC filter parameters must be changed.

    If you are running the code through IDE (Keil or IAR), you may add the below code ) inside AppBIASeqMeasureGen () and add to watch “AppBIACfg.MaxODR”, to know the maximum sampling rate allowed for the set configuration.

      AppBIACfg.MeasSeqCycleCount = AD5940_SEQCycleTime();

      AppBIACfg.MaxODR = 1/((( AppBIACfg.MeasSeqCycleCount + 10) / 16.0)* 1E-6)  ; //If Sysclk is16MHz

      if(AppBIACfg.BiaODR > AppBiaCfg.MaxODR)


      /* We have requested a sampling rate that cannot be achieved with the time it takes to acquire a sample.*/

    AppBIACfg.BiaODR = AppBIACfg.MaxODR;


  • With the default AFE configuration, max allowed ODR is 10Hz. 

    thanks,Actually it already exists.But the sampling frequency does not I want to know what BiaODR is for.  

  • Hi,

    MaxODR can be increased moe than 10HZ by changing the ADC filter configuration.

    It is 10Hz only for the default configuration.

    BiaODR is the Output data rate set by the user.

    MaxODR is the max allowed ODR calculated for the set AFE configuration.

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