Mentor v8.6_4 - page 481

Command Dictionary Set Clock Restriction
FastScan and FlexTest Reference Manual, V8.6_4 2-453
Examples
The following example specifies that the ATPG cannot create test patterns with
multiple clock lines active:
add scan groups g1 proc.g1
add scan chains c1 g1 si so
add clocks 1 clk1 clk2
set clock restriction on
set system mode atpg
add faults -all
run