I have one more issue. When having just an auxiliary channel on sometimes the output appears to be clipping on the bottom. As though the Primary Channel CH1 is adding an offset from its phase accumulator. It appears that based on whatever value the phase accumulator was at when the channel was turned off is added to the output of the AUX channels, which makes sense.
Is there a way to clear this to 0? Likely, Bit 1 of 0x03 (CFR) Clear phase accumulator, or 0x02 (FR2) bit 4 will do the trick.
Also, bit 0 of 0x03 (CFR) Sine Wave Output.
I will try this to see if it fixes the problem.