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SPI cannot get correct data from AD7790

Hello, everyone:

     I'm using AD7790 for A / D conversion, and get data from AD7790 using the SPI function of STM32F103.

      I configured it according to its Timing Diagram. However, I could not get correct data from AD7790. I think I configured all the registers, and tried to debug them in a variety of ways, but it still doesn't work.

      I`m looking forward to your help.

  • Hi,

    I would like to clarify if the SPI issue that you are having is that the part is totally not communicating with your controller? When you read the ID register, for example, are you not getting correct value or totally not getting any value? Can you send us a scope shot of your digital interface? Upon power up, with CS low, you should see that the DOUT/RDY pin is pulsing at selected output data rate. It might be also worth reading this thread which includes most of the frequently asked questions regarding sigma delta products. Digital Interface FAQ - Sigma Delta ADC

    Thanks,

    Jellenie

  • Thank you for your reply.

    I didn't get the correct value.No matter what number I send through SPI, the number returned is either 00 or FF.

    This is my hardware wiring diagram.

    The SPI works when STM32F103 acts as master and other devices as slave. However, it can not work properly with AD7790.