Timing problem with Cyclone-III Remote update

Hi guys,

I am trying to add a remote update functionality to my design.

It is Cyclone EP3C25E144C8 with Nios system on it.

When I add a Remote Update Controller to the SOPC system and recompile my project, Timing analysis fails. This critical path is inside the remote controller and relates to its clock.

At first, I fed a 40 MHz clock to the controller, as recommended in datasheet.

When timing failed, I lowered frequency down to 25 MHz. But timing analysis fails again, and the slack (negative) is worse than that at 40MHz!

Then down to 10 MHz - and again no success.

The problem is in clock hold, so I think lowering clock frequency

won't help. It's rather the design of the remote update component...

Have you got this problem?I need your advise.Thanks a lot!