ADE7878 sampling waveform - change sampling frequency

Hello,

I want to use the ADE7878 as dual-purpose function: using this internal functions to provide some information about metering, and using the sample data for protection purposes (ex: 5051 Relays). I want to use a Sliding Window DFT algorithm with a integer "x" points per cycle - how to change the internal sampling frequency in the ADE7878 to a multiple of 60 Hz (example: 128 points per cycle, fs=7680Hz) to use sampling values in a Sliding Window DFT ? Change the oscilator input is a viable alternative?

Thanks in regard,

Douglas.