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ADS7854: INTERFACE MODE and Data Write Operation

Part Number: ADS7854

Hi all

Would you mind if we ask ADS7854?

<Question1>
When INTERFACE MODE changes from 32-CLK, dual-SDO mode (default) to 16-CLK, dual-SDO mode, after changing, Frame (F+1) will be 16-CLK, dual-SDO mode, right?

<Question2>
In case of No operation is performed, SDO_A nad SDO_B output D13 to D0? 


Kind regards,

Hirotaka Matsumoto

  • Hello Matsumoto san

    Please see my reply below

    1.  When you are changing from 32 CLK dual SDO mode to 16 CLK dual SDO mode you have to write configuration register (CFR) bits as (CFR.B11 = 1, CFR.B10 = 0).  Data written into the CFR in a valid frame (F) determine the device configuration for frame (F+1)

    2. When you say no operation is performed, I believe you are referring to CS pin held high. When CS pin is high, SDO pins are tri stated. Let me know if this is what are you looking for

    Let me know if you need more information

    Thanks & Regards

    Abhijeet 

  • Abhijeet san

    Thank you for your reply!
    In relation to <Question2>, we are sorry that we would like to heard basic quesiton.
    What we would like to know is the method to get output data  from SDO_A and SDO_B using 16 CLK dual SDO mode.
    We understood Data Write Operation, however we could not understand "Data Read Operation".
    In order to get valid data(ADC output data) from ADC, what should we command via SDI?
    (What does it mean "No change in device configuration"?)

    Kind regards,

    Hirotaka Matsumoto

  • Hello Matsumoto san

    Here is the sequence for device configuration for your use case

    1. Device power up. 32 clock dual SDO mode is defualt mode for the device

    2. Frame 1: You write CFR register bits (CFR.B11 = 1, CFR.B10 = 0) to select 16 CLK dual SDO mode

    3. Frame 2: Give 16 clocks to get ADC data on SDO_A and SDO_B. Keep SDI pin low (for next frames) if you wish to remain in 16CLK dual SDO mode

    I hope this answers your question. Do let me know if you need additional information

    Thanks & Regards

    Abhijeet