buf_xbit :
A logic buffer gate with xbit-typed input/output’s.
The buf_xbit
primitive models a logic buffer gate with an inertial delay. It is suitable for processing digital signals of which precise timing information must be preserved.
The propagation delay of the logic gate is specified by the parameter delay
. The implemented delay is inertial
, meaning that if a new input event arrives before the previous input event propagates to the output, the output event will be overriden with the one corresponding to the new input event. If a transport delay behavior is desired, use the delay_xbit
primitive instead.
The parameter init_value
defines the initial output value at time=0.
The parameters valueX
and valueZ
define the mapped input values of logic X and logic Z, respectively. For example, if valueX
is set to 0, all input values corresponding to logic X are treated as logic 0. They can be used to suppress the propagation of logic X and Z values.
The parameter twostate
is provided for legacy support. When set to 1, the primitive enforces a 2-state output by producing logic 0 outputs whenever the input has a logic X or logic Z value. For the buf_xbit
primitive, this is equivalent to setting both valueX
and valueZ
to 0.
Input/Output Terminals
Name | I/O | Type | Description |
out | output | xbit | output signal |
in | input | xbit | input signal |
Parameters
Name | Type | Default | Unit | Description |
delay | real | 0.0 | seconds | propagation delay (inertial) |
init_value | logic | 1’bx | None | initial output value |
valueX | logic | 1’bx | None | mapped value of logic X |
valueZ | logic | 1’bz | None | mapped value of logic Z |
twostate | bit | 0 | None | enforce 2-state output |