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Original question:

AFE4404: AFE4404

AFE4404: using as a SPO2 sensor with 2-LED mode

Sara
Prodigy 50 points
Part Number: AFE4404

I want to use AFE4404 to measure spo2 level using 2-LED red and IR. I have interfaced the sensor but I am not able to get the IR led working and values of red and IR led are not being changed upon placing fingers on the sensor. Second issue is the led on time- how to calculate it and what values to be written on their register. I mean if I want red and IR LEDs to be on for 1 ms and off for 1 ms then how to decide the value of start and end counter. and Lastly what is the full sequences of on/off LEDs step by step in order to get the sensor working?

  • 0
    TI__Prodigy 520 points

    Hi Sara,

      You can use the EVM default config and make sure you are getting the expected result. Afterwards, you can use the EVM GUI to program the LED ON time which will generate all the required register settings.

    Regards,

    Midhun Raveendran

  • 0 in reply to Midhun Raveendran76
    Prodigy 50 points

    Hi Midhun Raveendran,

    Thank you for replying to my question. I did try with a default config (  did you mean the register values given in datasheet??) but didn't get the led readings.

    Also, I just received the AFE4404 EVM kit and I am trying to get the adc_rdy interrupts timings on the CRO. But I am not getting the image as shown in the user guide

    ( SLAU621A–May 2015–Revised December 2015) . So how should I find the interrupt timings and how should I configure the device in order to use as a spo2 measurement device?

  • 0 in reply to Sara
    TI__Prodigy 520 points

    Hi Sara,

     You should open the EVM GUI and click on RESET TO EVM DEFAULTS button and start capturing (or directly start capturing before doing any register modifications). After this, you can modify the registers and capture again to see that you are getting the expected result. Once when you finalize your register settings, you can export the register configurations that can be used in your custom board.

    Regards,

    Midhun Raveendran

  • 0 in reply to Midhun Raveendran76
    Prodigy 50 points

    Hi Midhun,

    Ok will try with defaults settings. One more question I have is the codes shown on the ADC capture values what does that value indicate? is it the direct red and IR values read from the registers?

  • 0 in reply to Sara
    TI__Prodigy 520 points

    Hi Sara,

      Codes are ADC codes read from result register.

    Regards,

    Midhun Raveendran