I'd like to enable the -retiming option of global optimization for just some instances in my project. Is it possible? How can I do it?
The problem is that retiming cause an error with DDR logic (see http://forums.xilinx.com/t5/Implementation/Fatal-error-during-mapping-of-ddr2-logic/td-p/103798 ) and I can't solve it. So I'd like to apply retiming only on my peripheral, I have to do it to improve the time-performances. Thank you!
You can do this in your RTL or UCF:
signal your_ddr_sig : std_logic;
(* register_balancing = "no" *)
In the UCF:
inst "your_ddr_register_instance_name" register_balancing "no";
Hope this helps...