User guide

12-11
Delays and Timing
2. At time 29 the input port toggles to 0 ending a nine time unit wide
value 1 pulse on the input port.
3. At time 30 the output port toggles to 1. The nine time unit wide
value 1 pulse that began at time 20 on the input port is propagating
to the output port because we have enabled transport delays and
nine time units is more than 80% of the ten time unit module path
delay.
4. At time 39 the input port toggles to 1 ending a ten time unit wide
value 0 pulse. Also at time 39 the output port toggles to 0. The
ten time unit wide value 0 pulse that began at time 29 on the input
port is propagating to the output port.
5. At time 46 the input port toggles to 0 ending a seven time unit
wide value 1 pulse.
6. At time 49 the output port transitions to X. The seven time unit
wide value 1 pulse that began at time 39 on the input port has
propagated to the output port but VCS has replaced it with an X
value pulse because seven time unit is less than 80% of the
module path delay. You also see at this time the following warning
message:
Warning : Time = 49; Pulse flagged as an error in
module_instance_name, value = StE.
Path: input_port --->output_port = 10;
7. At time 56 the input port toggles to 1 ending a ten time unit wide
value 0 pulse. Also at time 56 the output port toggles to 0. The
ten time unit wide value 0 pulse that began at time 46 on the input
port is propagating to the output port.
8. At time 60 the input port toggles to 0 ending a four time unit wide
value 1 pulse. Four time units is less than 50% of the module path
delay so VCS filters out this pulse and no indication of it appears
on the output port.