ADE7878 returning wrong data

Hi

I am using ADE7878 on my energy metering board, (designed by my own based on ADE7878 evaluation board)

Although the board is designed for 3 phase measurement, I have started testing with single phase inputs because we don't have 3 phase power at my workspace

Is connecting to 1 phase and neutral sufficient for using ADE7878 single phase?

I have used the attached code (for ATmega32) to read register values in ADE7878, when the power is not connected, ADE returns random values and when power is connected ADE returns zero when I read address 0xE510 (VAWV :  Instantaneous value of Phase A voltage)

or 0xE513 (AWATT:  Instantaneous value of Phase A total active power)

Thanks for your help