Hi, I have a synthesized (netlist) block called "block_A". I have put a constraint on the port "clk_A" during the synthesis of the block_A. Now, I want to use this synthesized block in upper level block, which doesn't have the "clk_A" port on it, but I would like to constrain it at this level. I used the following command in Ambit (using hierarchy): But, it doesn't seem to work. I would appreciate if somebody helps me in this. Also, what is the equivalent command in SYNOPSYS. Regards, Vipan