When I build an ML510 design with the xps_ethernetlite Core, I receive the following timing error:
Timing constraint: NET "Ethernet_MAC/Ethernet_MAC/phy_tx_clk_i" MAXSKEW = 5 ns;
1 net analyzed, 1 failing net detected.
1 timing error detected.
Maximum net skew is 5.013ns.
This is an invalid timing error from the timing engine, and it can be safely ignored. If this is your only timing constraint, you can disable the prevention of creating bitstreams by:
1. In XPS, select the Project pull down menu.
2. Select Project Options.
3. Select the Hierarchy and Flow tab.
4. Deselect "Treat timing closure failure as error".
This problem has been fixed in EDK 11.4, available at: