HARDWARE DESCRIPTION

Signals may only be declared in the declarative part of an Architecture(i.e. before BEGIN). Variables may only be declared in the declarative part of the process(i.e. before the BEGIN).

Signals Variables
Assignment
Operator <= :=

Use Represents Represents local
circuit interconnect storage

Scope Global Local to process
Signals Variables

Behavior Updated at Updated immediately
end of process
execution(new
value not immediately
available)


As mentioned earlier, the statements in a process are executed in sequence. Within processes, special sequential statements can be used. Remember, the following sequential statements may not be used outside of a process.