Keyword: CONSTANT

The constant keyword declares a constant of a type specified in the constant declaration.

A constant declaration includes—in this order—the reserved word "constant", the name of the constant, the optional reserved word "in", the type of the constant, and, optionally, an expression for the value of the constant.

If an expression for the value of the constant is not included in the constant declaration, then the constant is referred to as a deferred constant.  A deferred constant may only be included in a package declaration, while the complete constant declaration, including the expression which defines its value, must be included in the package body.

Examples

    constant RESET: std_ulogic_vector(7 downto 0) := "00000000";

    ...

    constant PERIOD: time := 80 ns;

LRM

    4.3