Waveform Register. When WSMP (Bit 3) in the interrupt enable register is
set to 1, this read-only register contains the sampled waveform data from
either Channel 1, Channel 2, or the active power signal. The data source
and the length of the waveform registers are selected by Bits 14 and 13 in
the mode register—see the Channel 1 Sampling and Channel 2 Sampling
sections.