reg4.vhd

来自「一本很好的关于学习VHDL的书,Fundamentals of Digital 」· VHDL 代码 · 共 21 行

LIBRARY ieee ;
USE ieee.std_logic_1164.all ;

ENTITY reg4 IS
	PORT ( 	D				: IN 	STD_LOGIC_VECTOR(3 DOWNTO 0) ;
			Resetn, Clock	: IN 	STD_LOGIC ;
			Q 				: OUT 	STD_LOGIC_VECTOR(3 DOWNTO 0) ) ;
END reg4 ;

ARCHITECTURE Behavior OF reg4 IS	
BEGIN
	PROCESS ( Resetn, Clock )
	BEGIN
		IF Resetn = '0' THEN
			Q <= "0000" ;
		ELSIF Clock'EVENT AND Clock = '1' THEN
			Q <= D ;
		END IF ;
	END PROCESS ;
END Behavior ;