Question

If a port declaration has a wire type (which is the default), or any other net type, then its direction controls how it can be connected as follows:

• An input can be connected to any expression of a compatible data type. If left unconnected, it shall have the value 'z.
• An output can be connected to a net type (or a concatenation of net types) or a compatible variable type (or a concatenation of variable types).
• An inout can be connected to a net type (or a concatenation of net types) or left unconnected, but not to a variable type.

Note that where the data types differ between the port declaration and connection, an initial value change event can be caused at time zero.