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Queries on AD9914 Parallel and Direct Mode

Question asked by soumyabumba on Jun 22, 2014
Latest reply on Aug 14, 2014 by LouijieC

I want to generate only single tone using AD9914. Here are few doubts I am having with respect to custom board design and programming in DIRECT MODE.


1. After a Master Reset the registers are loaded with default values. From this condition does any setting needs to be changed in any of the CFR registers to prepare it for taking FTW in the Direct Mode, F[3:0]=0010?

I want just to make F[3:0] permanently 0010, place the 32 bit FTW and apply IO_Update and the new frequency should come. Do I need to turn off the sync_clk and parallel port streaming enable if I want to apply IO_update?


2. If I do need to change some registers from the default values after reset I have to do it in parallel mode F[3:0]=0000 right? I do not want to use the serial mode. After reset what are the resistors I have to change? I am guessing only CFR2 to turn off sync_clk and enable profile mode to Profile 0. After this change can I switch to the Direct Mode by changing F[3:0]=0010?


3. I need only Profile 0. Can I permanently tie the PS0-PS2 to the device GND (exposed pad) on the PCB or do they need to be set to zero from the controller at any specific point of time during the programming sequence?


4. The initial revisions of AD9914 mentioned max clock frequency as 4GHz which was later changed to 3.5GHz? What will be the problems if I clock it at 4GHz. I am asking this because I have already a 4GHz oscillator with me.


5. I need some help in  programming the parallel mode of AD9914 in Verilog/VHDL should i need to? I will greatly appreciate if someone who has already developed the controller on fpga gives some tips.


Thank you