I've configured my ADS1261 (on the ADS1261EVM board) in this way:
-) REFP: AVDD (internal) ; REFN: AVSS(internal)
-) MUXP: AIN3; MUXN: AINCOM
I've plugged a sensor that has a signal that goes from 0 to 5V between AIN3 and AINCOM. I can read ADC points from the evaluation software but I've 2 questions:
1) How can I reach 24 bit resolution? I see that the ADC values goes from 0 to 8388608; it seems it is using only 23bits; as far as I can understand, if I set that the reference has to go from AVSS (0V) to AVDD (5V) I think that the converter has to give me values referring to these 2 points.
2) When my signal is at (for example) 1 V I read around 1660000 ADC points which seems correct if we refer to the 23 bits above. But if I change the PGA gain to 2V/V I see that the points goes up to around 2210000. I figured out that they had to double (around 3300000 for example).
What am I doing wrong?