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AFE4300EVM-PDK: Multiple sensing electrodes

Jinke Takken
Prodigy 30 points

Part Number: AFE4300EVM-PDK
Other Parts Discussed in Thread: AFE4300

Dear Sir/Madam,

I would like to measure with 2 pairs of sensing electrodes and 1 pair of injection electrodes at the same time.

Is this possible with the AFE4300EVM-PDK evaluation board?

From the data sheet, it seems to me that it is possible to turn on 1 sensing pair at the time.

Thanks in advance.

Jinke

  • 0
    TI__Genius 12575 points
    Hi Jinke,

    Yes you are correct you can connect two pairs of sense electrodes but its conversion will happen sequentially.
    You have to write registers to select the sense electrode yourself.

    Regards,
    Prabin.
  • 0 in reply to Prabin Yadav
    Prodigy 30 points
    Hi Prabin,

    Thank you for your answer. In fact, I tried to make a Matlab program to write the registers with help of the Message Communication Protocol document.

    After some attempts, I managed to write the registers according to the values in the device GUI (like I select the boxes in the GUI). I can also read back the register values and they are correct. For example: for changing the sample frequency to 860 sps in ADC_CONTROL_REGISTER1, I send 'w015170?' and then I send 'r01?' and I read back 5170 (also, the display of the AFE4300 EVM PDK board shows this value). However, I am not able to measure the potential difference over 1 pair of measurement electrodes (I keep receiving the 0A 0D default value) in Matlab.

    When I adjust the registers in the GUI and try to read the measurements through Matlab, it does work. In my Matlab code, I first set all registers to the default values and then I adjust all the register values. Is there something else that I should add to my Matlab code, except all the register values?

    Regards,
    Jinke
  • 0 in reply to Jinke Takken
    TI__Genius 12575 points
    Hi Jike,

    What command do you give to capture the data from the EVM?
    Did you try reading the AFE's output register (i.e 0x00) directly ?

    Regards,
    Prabin