In ISE - 2022.2 English - UG911

In ISE, the following period constraints are equivalent:

NET "clk" TNM_NET = sys_clk;

TIMESPEC TS_sys_clk = PERIOD "sys_clk" 10 ns HIGH 50%;

NET "clk_IBUF_BUFG" TNM_NET = sys_clk;

TIMESPEC TS_sys_clk = PERIOD "sys_clk" 10 ns HIGH 50%;