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Original question:

ADS7142: ADS7142 Adress selection

ADS7142: Read value error

Naizeng Wang
Expert 5970 points

Part Number: ADS7142

Hi team,

My customer is using ADS7142 in server, the input voltage is 1.7V but readback value is 0.1V. they are using the manual mode auto sequencing. 

image.png

the initializaiton steps is shown as below, it seems good. 

share_image_1785245644895.jpeg

 

there are two reasons may lead to this issue.

(1) the initializaiton steps is not good. some chips can work well, some cannot. 

(2) the chip damaged. 

For the (2) suspect, customer also reads the 04h register, it is 0A. but in datasheet, the 3bit should alwasy be 0. so customer thinks that the chip damaged. Could you share your insight? why the 3bit becomes 0? 

 

  • 0
    TI__Mastermind 20880 points

    Hello,

    Would you be able to provide a full logic analyzer capture of the I2C lines SDA and SCL? Timings will be important, and it is also good to verify that the I2C transactions are doing the operations that are expected.

    What is the intended functionality they are trying to achieve? Do they only have channel 1 enabled, or will they use auto-sequence mode to read from both channel 0 and 1?

    Step 6: Abort Sequence does not look entirely correct.  Bit 0 has to be set to 1 in order to abort the sequence. 

    Additionally, would you be able to share a schematic to understand the input signal they are measuring, and determine whether it is an analog issue?

    Regards,
    Joel