creating clocks

you must specify all of the clocks in the design by using the create_clock cmd. This cmd creates a clock at the specified source.  A source can be defined at an input port of the design or an internal pin.

PT traces the clock network automatically so the clock reaches all registers in the transitive fanout of its source.

A clock you create with the create_clock cmd has an ideal waveform that ignores the delay effects of the clock network. After you create the clock, you must describe the clock network to perform accurate timing analysis.

The create_clock cmd creates a path group having the same as the clock.
This group contains all paths ending at points clocked by this clock.

for example:
pt_shell>create_clock -period 10 -waveform { 2 4 } { C1 CK2 }

to create a clock on ports C1 and CK2 with a period of 10, a rising edge at 2, and a falling edge at 4.

C1 clock waveform,