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Data not read from Multiple AD7190 IC's

Hello Everyone,

       MSP432P401M controller is interfaced with 8 AD7190 Ic's through SPI communication. I am using 3 wire SPI  interface. When I try to communicate with single AD7190 IC's I can successfully read load cell/ strain gauge data. But, when I trying to communicate data from 1,2 and 3rd IC simultaneously then 3rd IC is not selected..Instead of 3rd the data read from 2nd iC so if load cell data will change then same value will change for 2nd and 3rd IC.

the sequence is :-

-CS low

-Delay in us

-write in communication register for channel selection 1

-wait for RDY pin low

-read data

-write in communication register for channel selection 2

-wait for RDY pin low

-read data

-Delay in us

-CS high.

-same sequence to read data from 2nd,3rd IC..

Please suggest.

Parents Reply
  • Hi,

    1. 3MHz SCLK should not be a problem. The device works upto 5MHz.
    2. Have you enabled channel 1 and 2? Is the SPI write working? 
    3. There are multiple scenarios where RDY goes high.
      1. If SYNC is low, DRDY pin is pulled high.
      2. If the data is being updated, DRDY goes high.
      3. If calibration is enabled, DRDY goes high.

    Please go through the datasheet DIGITAL INTERFACE section on page 29 for more info.


    Vikas J

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