creating a virtual clock

You can use the create_clock cmd to define virtual clocks for signals that interface to external (off-chip) clocked devices.  A virtual clock has no actual source in the current design, but you can use it for setting input or output delays.

To create a virtual clock named vclk,

pt_shell> create_clock -period 8 -name vclk -waveform { 2 5 }

The vclk has the waveform shown in below,