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ADS7142: ADS7142 wrong channels returned values

S L1
Prodigy 10 points

Part Number: ADS7142

Hello,

I'm working with the ADS7142 device using a STM32 ARM M4 processor with I2C. I have configured the 'Manual Mode Dual Channel Sampling' exactly as in the

'TN4C1294 Interface to ADS7142 Software Library' documentation (SBAA288–July 2018), page 25, Figure 14. The I2C communication works well (I see on the

scope the messages and the quality of the signal) but the data returned by the channels is not correct. The received values are changing all the time but are too big

and the measured voltage should be closed to zero. I see on the scope that the device indeed returns the values that I read on the buffer. The processor and the device

are on a custom designed board and the hardware engineers are confirming that is no problem with the hardware. I have tried to configure also only a channel  but

the result is the same.

Please advise how to debug this issue.

Thank you in advance,

Sorin.

  • 0
    TI__Mastermind 25070 points

    Hello,

    Would you share exactly what you are seeing vs what you expect.

    Using a known DC value to test is best, this way you know what the output should be

    If you could also share a scope shot of the digital communications, showing the correct readings from buffers, and incorrect output data.

    If you are able to read registers from the device, it should not be a timing issue.

    When running these test, also make sure the AVDD power line is stable and clean, as this works as the voltage reference for the ADC as well. If there is any noise on this, it will reflect in the output. Also, checking the input during test with a probe or multimeter to reverify that input is indeed where it should be

    Regards

    Cynthia