I am having a strange issue with the ADE7878. We're testing our boards and we have established successful I2C communication to the ADE7878. We have been able to read linear output from the RMS registers for voltage and current on all channels except for AIRMS and CVRMS which remain a constant low level output.
I have done continuity checks from the board inputs to the C voltage and A current pins on the ADE7878, and even measured the 60 Hz test sine wave apparently going into those pins, yet no output for those two channels.
We are experiencing some board issues, so it could still be something related to a bad trace, but I wanted to check if I'm overlooking some obvious configuration that might render the AIRMS and CVRMS outputs as essentially zero all the time?
Additionally, this version of the board does have some traces running underneath the ADE7878. We now know that we must not do this as the pad under the ADE7878 should not connect to anything (and really needs to be soldered to an isolated pad for strength anyway).