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假如在一个matchgroup中,有10个pinpair,由5个网络(net/xnet均可)生成,每个网络对应2个pinpair。
2 Y K: m9 N& m$ Q& R那么如果你选择local 局部等长,那么虽然10个pinpair虽然在一个matchgroup中,但是匹配只会在同一net/xnet对应的那2个pinpair之间进行,和其他8个pinpair没关系,但是global的话就是全部10个pinpair均进行匹配。所以, 一般内存什么的延时设置都是global
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PS,软件自身的参数/功能不确定,直接F1是最有效直接的,顺便给你看下帮助说明。2 M9 W, }) m0 @# W, `% K$ @& [
6 w) [9 G L1 j: c+ x With a Local scope, all pin pairs occupy a single Match Group; Constraint Manager compares pin pairs to only pin pairs in the same Xnet. In Figure 2-5, Constraint Manager compares pin pair U17.7:U10.12 only with pin pair U17.7:U11.12 because they come from the same Xnet, ADDR5.8 K5 v! S! M7 _' C& {* x% Y) T
With a Global scope, Constraint Manager validates pin pairs collectively in the (single) Match Group, as shown in Figure 2-6. In this scenario, Constraint Manager compares pin pair U17.7:U10.12 to all other pin pairs in the Match Group. |
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