dec4to16.vhd

来自「一本很好的关于学习VHDL的书,Fundamentals of Digital 」· VHDL 代码 · 共 25 行

LIBRARY ieee ;
USE ieee.std_logic_1164.all ;

ENTITY dec4to16 IS
	PORT (	w	: IN 	STD_LOGIC_VECTOR(3 DOWNTO 0) ;
			En 	: IN 	STD_LOGIC ;
			y	: OUT 	STD_LOGIC_VECTOR(0 TO 15) ) ;
END dec4to16 ;

ARCHITECTURE Structure OF dec4to16 IS
	COMPONENT dec2to4
		PORT ( 	w 	: IN 	STD_LOGIC_VECTOR(1 DOWNTO 0) ;
				En 	: IN 	STD_LOGIC ;
				y	: OUT 	STD_LOGIC_VECTOR(0 TO 3) ) ;
	END COMPONENT ;
	SIGNAL m : STD_LOGIC_VECTOR(0 TO 3) ;
BEGIN
	G1: FOR i IN 0 TO 3 GENERATE
		Dec_ri: dec2to4 PORT MAP ( w(1 DOWNTO 0), m(i), y(4*i TO 4*i+3) );
		G2: IF i=3 GENERATE
			Dec_left: dec2to4 PORT MAP ( w(i DOWNTO i-1), En, m ) ;
		END GENERATE ;
	END GENERATE ;
END Structure ;