精品文档---下载后可任意编辑library ieee;use ieee
std_logic_1164
all;use ieee
std_logic_unsigned
all;entity counter is port(clk,clk1,en,clr:in std_logic; ledout:out std_logic_vector(6 downto 0); scanout:out std_logic_vector(1 downto 0);co:out std_logic);end counter;architecture a of counter issignal cnt:std_logic_vector(7 downto 0);signal led:std_logic_vector(6 downto 0);signal scan:std_logic:='0';signal hex:std_logic_vector(3 downto 0);begin process(clk) begin if(clk'event and clk='1')then if en='1'then if clr='1'then cnt'0'); else if cnt="00111111"then cnt