The no_clock check reports the groups of active
leaf clock pins with no clock definition. Each group is associated with a clock
source point where a clock must be defined to clear the issue.
% check_timing -override_defaults no_clock
1. checking no_clock
--------------------
There are 15633 register/latch pins with no clock driven by root clock pin: sysClk
(HIGH)
There are 148 register/latch pins with no clock driven by root clock pin:
mgtEngine/ROCKETIO_WRAPPER_TILE_i/gt0_ROCKETIO_WRAPPER_TILE_i/gtxe2_i/TXOUTCLK
(HIGH)
There are 8 register/latch pins with no clock driven by root clock pin:
usbClkDiv2_reg/C (HIGH)With check_timing, the same clock source pin or port can appear in several groups depending on the topology of the entire clock tree. In such case, creating a clock on the recommended source pin or port will resolve the missing clock definition for all the associated groups.