It should be related to SPI clock and not the CLKIN frequency.
A0 and A1 should hold their value for the duration of the data read and after
that they can be released or set to a new state.
Upon review and analysis wrt AD2S1210 datasheet. There appears to have typo
errors in the timing parameters. Have liaison with the author for this
The hold time for A0, A1 should be related to SPI
clock and not the CLKIN frequency. Currently the datasheet is being revise to
include these changes. Please see attached temporary cut down version for the