We're having some trouble setting up our AD7147 and were wondering what the best way to check if it is indeed working. We have looked at the AC Shield Signal on an oscilloscope and it does not look as expected (see attached photo) - it goes from 0V to 3.3V but does not look like a proper square wave. We have also tried to do a serial read from some of the device's registers that we know should be initialized to non-zero values, but the CDC never reads out any non-zero data.
How would you suggest trying to debug this? So far, the only pins we have connected are Vbias (including the 100nF capacitor), Vdrive, Vcc, and ground. We've connected the serial pins as well when needed. All the CIN pins are floating. Is that a problem?