ADS131M02: After connecting analog inputs of different voltages, the channel data was not converted into corresponding digital quantities

Hi Experts:

     I have a question and I hope you can help me.

    Why does the digital data converted by ADS131M02 not change after connecting different voltage analog inputs(default configuration, The external crystal oscillator is 6.25Mhz)? 

These two images are communication data sampled with only channel 1 enabled. And AI1 is 5V input.

Additionally, the response of my SPI communication read/write register command is correct.

The following diagram shows the principle of AI sampling：

Alice：

Hello，

      Could you get right value for fixed input signal?

      Can it work correctly in "8.4.3.1 Continuous-Conversion Mode"?

       ADS131M02 2-Channel, Simultaneously-Sampling, 24-Bit, Delta-Sigma ADC datasheet (Rev. A) (ti.com)

,

?? ?：

I can't obtain the correct value of the fixed input signal. I configured the continuous-conversion mode, but still haven't received the correct value for the fixed input signal. Maybe you have any suggestions?

,

Alice：

Hello，

     The /DRDY pin is an active low output that indicates when new conversion data are ready.

     Before reading data from chip,

     please check "Figure 8-23. Reading a Single Register" for "8.6.1 ID Register" reading to confirm SPI timing,

     and "Figure 8-25. Writing Registers" to configure chip based on SBAC254 Support software | TI.com

,

?? ?：

The problem has been identified. It is a configuration issue with my ADS131M02. Thank you for your assistance.