Reply by Gerhard Hoffmann November 24, 20052005-11-24
Hi all,

is there a way to access the phase accumulator in Xilinx DDS 5.0?
(preferably from VHDL)

I'd like to determine the carrier phase between two modulated signals
by phaselocking an NCO on each one and then subtracting the phase
accumulators.

Given that there is a great DDS already,  I dislike reinventing it
just to tap an internal signal.

BTW the register interface is nice if  I want to setup everything with a
microcontroller. But ---  in a pure hardware environment it is clumsy to
multiplex frequency word and phase modulation to a 32 bit data bus
+ address line + WE,   knowing the first thing to happen is that they will
be
demultiplexed again into different registers. In addition,  the update rates
are halved    and potentially simultaneous frequency/phase updates need to
be scheduled.
(Options for DDS 5.1???)

best regards, Gerhard