DC综合的时候会出现很多这种warning，求助

eeleader-mcu

DC综合的时候会出现很多这种warning，求助 [复制链接]

DC综合的时候，时序slack为负，综合的信息会出现很多这种warning，
Warning: The following cells only drive
        asynchronous pins of sequential cells which have no
        timing constraint. Therefore retiming will not optimize
        delay through them:
        digital2/mult13/*cell*63670 (CLKBUFX20TF)
        digital2/mult13/*cell*63667 (CLKBUFX20TF)
        digital2/mult13/*cell*63668 (CLKBUFX20TF)



需要怎么修改约束或设置啊，谢谢