Question on using ODDR

Hello guys, I am working on a virtex 5 and trying to read out data from
internal distributed ROM at 250MHz. Then in order to increase data rate, I
choose use ODDR which is followed by OBUF. But in the MAP I have this kind
of errors at all the output of ODDR as following,

"ERROR:Pack:1569 - The dual data rate register
QPSK_wave/LOOP_DDR_A[6].ODDR_A
   failed to join an OLOGIC component as required."

I don't have any idea to solve this error. Is there someone can give me
some hint?

Another question, I have also tried to use OSERDES which is
parallel-to-serial converter before OBUF. Then the design pass the map but
in place and route it came out the warning as following,
"Route:436 - The router has detected an unroutable situation for one or
more connections. The router will finish the rest of the design and leave
them as unrouted, The cause of this behavior is either an issue with the
placement or unroutable placement constraints."
and occured in all the output pin of OSERDES. How to solve this? 

Is there any other method to increase data rate? When I reached to 500MHz,
the timing problem was always with me in post route simulation. 

Thank you for help!!

http://lmgtfy.com/?q=instantiate+oddr+virtex+5+site:xilinx.com

;-) 

>http://lmgtfy.com/?q=instantiate+oddr+virtex+5+site:xilinx.com
>
>;-) 
>
>
>
Thank you for reply. But I have already read the library and the template
of the ODDR. However my problem is in the map. The unit cannot be mapped. I
want to figure out how to solve this situation.

"lioncat" <dominghang@hotmail.com> wrote in message 
news:gI2dnYJKlIWPz5nXnZ2dnUVZ_oGdnZ2d@giganews.com...

>>
> Thank you for reply. But I have already read the library and the template
> of the ODDR. However my problem is in the map. The unit cannot be mapped. 
> I
> want to figure out how to solve this situation.

So, even if you use the exact template they suggest, maybe with a really 
simple experimental design, the map doesn't work? Did you also try looking 
at XAPPs with DDR? What about the FDDRRSE part, did you try that?
HTH., Syms. 

>
>"lioncat" <dominghang@hotmail.com> wrote in message 
>news:gI2dnYJKlIWPz5nXnZ2dnUVZ_oGdnZ2d@giganews.com...
>
>>>
>> Thank you for reply. But I have already read the library and the
template
>> of the ODDR. However my problem is in the map. The unit cannot be
mapped. 
>> I
>> want to figure out how to solve this situation.
>
>So, even if you use the exact template they suggest, maybe with a really

>simple experimental design, the map doesn't work? Did you also try
looking 
>at XAPPs with DDR? What about the FDDRRSE part, did you try that?
>HTH., Syms. 
>
>
>

Thank you for reply. I have tried your suggestion to use the ODDR in a
simple experimental design. And it turns out success in MAP. So I took a
deep look at my older design. Then I think the problem is that in it the
ODDR is not directly following by the OBUFDS, but a flip-flop. Therefore I
changed the design and it passed the MAP and Place and Route. Maybe it will
also work with OSEREDS.

Thanks a lot!

Still one question

After map, place and route, I ran the post route simulation, then I have
the error as following,

# ** Error: /X_ODDR SETUP High VIOLATION ON D1 WITH RESPECT TO C;
#   Expected := 0.434 ns; Observed := 0.386 ns; At : 68993.604 ns
#    Time: 68993604 ps  Iteration: 2  Instance:
/test_03_04_09/uut/loop_ddr_c_4_oddr_c

Does anyone have idea about solving this kind of error?