ADS1299 GPIO and ADC data syncronization

Vladimir Savinov

Other Parts Discussed in Thread: ADS1299

Hi!

from ADS1299 datasheet:

For the ADS1299, the number of data outputs is [(24 status bits + 24 bits x 8 channels) = 216 bits].

The format of the 24 status bits is: (1100 + LOFF_STATP + LOFF_STATN + bits[4:7] of the GPIO register

The question - how GPIO input states synchronized with the ADC samples data?

Thanks!

0 Brian Pisani over 8 years ago

Vladimir,

The states of the GPI pins are latched into the status word <1us before DRDY comes low.

Regards,
Brian Pisani

0 Vladimir Savinov over 8 years ago in reply to Brian Pisani

Thanks for your answer!
But how it is related to the time converting analog data to digital?

0 Brian Pisani over 8 years ago in reply to Vladimir Savinov

Hey Vladimir,

This device is a delta-sigma ADC which means it is sampling constantly and outputs the average of many samples. Therefore it is not applicable to talk about an event's relationship to the "sampling time". Here are a few articles that discuss how delta-sigma ADCs sample:

e2e.ti.com/.../delta-sigma-adc-basics-understanding-the-delta-sigma-modulator
www.planetanalog.com/author.asp

Regards,
Brian Pisani

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