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ADS131E08: SPI Communication Error

Nicky Lim
Genius 3195 points
Part Number: ADS131E08


Hello,

Make circuit as below, and try to communicate via SPI but cannot read it.

1. Could you review below schematic, and let me know if there is any fault or missing?

2. Is there any way to check if ADS131E08 is working or not?  Not via SPI.

Regards,

Nicky

  • 0
    TI__Mastermind 38745 points

    Hey Nicky,

    The schematic looks fine. Find below the VCAP pin voltages. They can measure these to see if they match the ideal values:

    VCAP1: 1.2 V

    VCAP2: (AVDD+AVSS)/2

    VCAP3: 1.9 + AVDD

    VCAP4: (REFP+REFN)/2

    Otherwise, it may very well be an SPI issue that they will have to debug. This blog has some advice about debugging SPI issues.

    Regards,

    Brian Pisani

  • 0 in reply to Brian Pisani
    Genius 3195 points
    Hi Brian,

    SPI issue is cleared.

    During Analog Data reading , its error rate is too big.
    So, she measured Vcap voltage as you recommend, but Vcap4 and Vref value are too low as below.
    She set CONFIG3 register as 0x68 and AVdd is 5V.

    VCAP1: 1.194 V
    VCAP2: 2.506 V
    VCAP3: 6.99V
    VCAP4: 0.005V
    VREFP : 0.122V

    Could you let me know why its error rate is too big, and VCAP4 value is too low?

    Regards,
    Nicky
  • 0 in reply to Nicky Lim
    TI__Mastermind 38745 points
    Hey Nicky,

    You will have to change CONFIG3 to 0xE8 to turn on the reference. That should fix the problems you are having.

    Brian