User guide

2-39
Modeling Your Design
Hhigh
X unknown (don’t care)
Ttristate
l low (2 or more DUT drivers active)
Testbench Level (only z drivers from the DUT)
h high (2 or more DUT drivers active
Drivers Active on Both Levels
0 low (both input and output are active with 0
values)
1 high (both input and output are active with 1
values)
? unknown
F tristate (input and output unconnected)
A unknown (input 0 and output unconnected)
a unknown (input 0 and output X)
B unknown (input 1 and output 0)
b unknown (input 1 and output X)
C unknown (input X and output 0)
c unknown (input X and output 1)
f
unknown (input and output tristate)