I've been tinkering with an HMC988LP3E prescaler along with a few other chips with the goal of making an RF frequency counter shield for the Arduino due. All has been going well except for one thing, I have so far been unable to get the HMC988 chip to actually recognize any commands. It powers up just fine, and the divider seems to be functioning, but I have been unable to elicit any response from the GPO, change the divide setting, or enable the internal biasing for the inputs.
To the best of my ability to tell, the commands I have been sending match the timing diagrams in the data sheet perfectly,and the logic levels and the data being sent are all correct. I have spent several days now trying to discover what is actually going wrong to no avail.
my question then is, are there any requirements for it to recognize incoming data that aren't explicitly stated in the data sheet? Is there a rise time requirement I might not be meeting on the clock or SLE signals? Or any other phenomenon that could explain it not recognizing incoming data?