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ADS1260: Internal Reference not working

Frank Roeder
Prodigy 30 points
Part Number: ADS1260

Hello,

If I configure the internal reference according to the data sheet, I always get the REFL_ALM (Reference Alarm) error.

It's explained quite simply in the data sheet but it doesn't work.

I write 0x10h to register REF.

The ADC aborts its conversion and returns register STATUS = 0x0Eh (REFL_ALM=1).

With an external reference

REF = REF_MUX_P_AIN0 | REF_MUX_N_AIN1;

REF = 0x0A

everything works, not erros.

Do you have any special instructions for using the internal reference?
Has it ever happened that the internal reference does not work in the ADS1260? Are there ERRATA sheets?

Regards
Frank Roeder

  • +1
    TI__Mastermind 35241 points

    Hi Frank,

    It sounds like I am missing some information based on what you have provided thus far

    Frank Roeder said:

    I write 0x10h to register REF.

    The ADC aborts its conversion and returns register STATUS = 0x0Eh (REFL_ALM=1).

    The REF ALARM doesn't affect the ADC conversion process - even if the VREF becomes disconnected, the alarm bit just tells you this occurs, but the ADC will continue to convert. So it is unclear to me why the ADC is aborting the conversion in your case. Are you performing this action because you read the REF_ALM bit in the STATUS byte? You imply that the ADC is taking these actions on its own, which suggests a much larger issue.

    Have you tried reading back the register write when you select the internal VREF i.e. when you write 0x10h? Is this WREG successful?

    Do you have the required 10uF capacitor on the REFOUT pin of the ADS1260?

    It might help to explain in more detail exactly what occurs after the WREG to turn on the internal VREF. If you think that logic analyzer data will make it more clear, please send that along as well.

    -Bryan