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AFE4404: constants in calibration_AFE4404.c

Konan Kim
Prodigy 210 points
Part Number: AFE4404

Hi,

I’ve analyzed calibration_AFE4404.c to figure out the main concepts. But to apply this code to my HW (SFH7072), the following constant values should be clarified.

1. ADC_CODE_AMB_DAC_MIN, ADC_CODE_AMB_DAC_STEP are defined initially with some values.

    Can these values be used for any LED-PD module ? How these values were obtained ? (by calling OFFSET_DAC_Code_Est ?)

    Theses two values are commented out in ‘OFFSET_DAC_Code_Est(), it means the initially defined values are used instead of calling OFFSET_DAC_Code_Est().

2. Regarding Ipleth_array[5], this array have predefined values.

    How these values were obtained ? (by measuring or by calculating something ?)

    Are theses values valid for any LED-PD module ?

3. Regarding Meas_DC_1K_1code_10CTR and Meas_DC_1K_500nAPleth,

    What are the meanings of them ?

    How the values were obtained ? (by measuring or by calculating ?)

    Are the values valid for any LED-PD module ?

Thanks in advance.

Konan

 

  • 0
    TI__Genius 12575 points
    Hi Konan.

    Here are few answers.

    1) Parameters for AMB DAC doesn't depend on LED-PD module. It only depends on AFE.
    2) Ipleth_array depends on LED-PD module, you can measure on your specific module.
    3) I will check this and get back to you.

    Regards,
    Prabin
  • 0 in reply to Prabin Yadav
    Prodigy 210 points

    Hi Prabin,

    Thanks for quick reply. I have additional questions.

    1) Thanks. I see.

    2) Regarding the measurement of Ipleth_array, should I measure IPD using an oscilloscope or calculate from TIA output ? Is this Ipleth_array applicable to all subjects ?

    3-1) I think I understand the meaning of the variables. But how the 10CTR was obtained ? (CTR of 10nA/mA)

       CTR needs to be calculated by measuring the Ieff(Isig actually by subtracting Iamb from IPD) which will be calculated from Rf and TIA output voltage.(right?)

    3-2)  Is calculated CTR common for all phases if green, red and ir are all used ?

    Regards,

    Konan