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ADS1115 - delay required for channel switching

sathvik ashok
Prodigy 20 points
Other Parts Discussed in Thread: ADS1115

Hi,

I am using ADS1115 with all the 4 channels @64SPS in round robin method as follows:

Configure & Start Conversion for Channel 1

Wait

read ADC value Channel 1

Configure & Start Conversion for Channel 2

Wait

read ADC value Channel 2

Configure & Start Conversion for Channel 3

Wait

read ADC value Channel 3

Configure & Start Conversion for Channel 4

Wait

read ADC value Channel 4

Is there any minimum delay is needed between the configure the next ADC channel after reading the current ADC Channel?

Regards,

Sathvik.

  • 0
    TI__Guru* 97795 points
    Sathvik,


    The delay needed for good data while changing channels depends on the ADC mode of operation. There are two modes of operation: single-shot mode, and continuous conversion mode. In one-shot mode, the next conversion after the mux change will be the expected result with the new mux setting.

    In continuous conversion mode, the mux setting doesn't change in the middle of a conversion. The device will complete the conversion it is in, make the change in the mux, and then complete a new conversion. In continuous conversion mode, the device is continuously converting and you never really know when the conversion starts and ends.

    If you are switching channels, continuous conversion mode takes longer, because you need to wait the length of two conversions to be absolutely sure that the mux change has taken place and that the new data with the mux change is ready. In single-shot mode, you set the mux and start taking the data. You'll only need to wait for a single conversion (+10% of the data period to account for the data rate variation).

    There are a few older posts that discuss this timing:

    e2e.ti.com/.../358836

    e2e.ti.com/.../242635

    e2e.ti.com/.../485334


    Joseph Wu