default values of wire and reg

[bharath9]

hi,

what are the default values of wire and reg?

 

[artmalik]

There is no default value... you have initialized the value of the "reg" ..it is just like a variable in any programming language. On the other hand wire is a connector you don't have do anything with this. It will take the value of output to which it is connected.

 

[dave_59]

I think you meant to ask what are the default initial values of wire and reg. The answer is simple for reg: the X state.

The answer is not so simple for wires, because wires do not store a value. Wires are the resolution of driver values. See my blog https://go.mentor.com/wire-vs-reg.

If a wire has no drivers, it resolves to the Z state. However, the initial resolution of wires at time zero is not defined in the LRM. Some simulators have chosen to make all resolve to X initially, and then move to whatever resolved value to that the wire always creates an event.