Mentor v8.6_4 - page 789

Timing Command Dictionary SET CYCLE
FastScan and FlexTest Reference Manual, V8.6_4 A-37
time 250. The only event allowed at time 200, which is the original end of the test
cycle, is forcing the clock inactive. The next event, which is the non-return pin
force, occurs at the start of the next test cycle, which is time 250ns.
Note that non-return pins change only once during the test cycle. The “cntrl” pin
could change at either 50 or 150. In this example, it changes at time 50. Likewise,
the bidirectional pins could change at either time 70 or 170. In this case, they
change at time 70.