ise布线没有布通，看到的是pll相关的信号

574920045

WARNING:Route:436 - The router has detected an unroutable situation for one or more connections. The router will finish the rest of the
   design and leave them as unrouted. The cause of this behavior is either an issue with the placement or unroutable placement constraints.
   To allow you to use FPGA editor to isolate the problems, the following is a list of (up to 10) such unroutable connections:
WARNINGar:100 - Design is not completely routed. There are 2 signals that are not
   completely routed in this design. See the "WRsdram.unroutes" file for a list of
   all unrouted signals. Check for other warnings in your PAR report that might
   indicate why these nets are unroutable. These nets can also be evaluated
   in FPGA Editor by selecting "Unrouted Nets" in the List Window.
该如何解决！这个看不懂，是太远了吗？能对位置进行调节吗？等大师啊！！！