I found the below description in the datasheet as is shown in attached file.
But I can not find any detailed description on the address 02h, Bit 3. I have
no idea how to set the bit as either input or output. Would you pls give your
professional advice on it?
The DATACLK pin can only be an output. The pin description is error, since we
do not support DATACLK as an input signal.
I would recommend other devices be considered for new designs instead of the
AD9777. The AD9779A or the AD9125 are newer devices that should be better
alternatives. The AD9777 power consumption and performance is unlikely to be
as good as either of the newer devices.