Greetings,
I am implementing a design whose system clock is generated by an MGT (the TXOUTCLK pin), based on higher frequency differential reference clock inputs to that MGT. The frequency generated at TXOUTCLK is correct, but the issue is that Xilinx ISE (7.1i, SP4) does not route this clock as a CLK Net.
The particular error, generated after PAR, is "WARNING:Route - CLK Net: net_name may have excessive skew because xx NON-CLK pins failed to route using a CLK template."
This design cannot tolerate the max skew that is reported (about 20% of a period), or the resulting max delay of about 40%. How can I force this net to use the CLK template I specified in the UCF, or otherwise remedy this issue?
Thanks much, Julian Kain