Hi ADI Engineer Zone
We are in the process of fault-finding an issue that uses AD9914.
We have written the register CFR3, Control Function Register 3 - 0x02, its default value of 0x0000191C.
Note here the bit positions 7, 23 and 24 to 31are defined as OPEN.
After the initial write when we read this register repeatedly the returned value some times changes to 0xFE00191C and stays the same.
Here the bits positions 24 to 31 which are defined as "OPEN" have changed.
Is this normal behaviour for the registers with "OPEN" bit positions?
Hence I wanted to look deeper into the definition of "OPEN" and "RESERVED" in the data sheet.
Can you please guide me to the section in the data sheets of any the products AD9910 or AD9914 or AD9915 where the meaning of "OPEN" and "RESERVED" are defined or specified with respect to the register values.
In these data sheets there are many notes with respect to hardware parameters why is "OPEN" and "RESERVED" mentioned?
AD9917-1 mentions the values of some registers to be "BLANK" which I assume is similar to "OPEN". At least in AD9517-1 it mentions "It does not matter what data is written to blank registers".
I can understand "RESERVED" register values should not be modified from their default values. But what about "OPEN" register values in these devices.
Regards
Diva
