hou.vhd

来自「智能化微机测量和控制技术的迅速发展和广泛应用己经渗透到国民经济的各个部门。不但国」· VHDL 代码 · 共 20 行

--------24进制计数器模块  计数输出为小时的数值
library ieee; 
use ieee.std_logic_1164.all; 
use ieee.std_logic_unsigned.all; 
------------------------------------
entity hou is 
port(en,clk,clr:in std_logic; 
h1,h0:out std_logic_vector(3 downto 0)); 
end hou; 
-----------------------------------------
architecture hour_arc of hou is 
begin 
process(clk) 
variable cnt0,cnt1:std_logic_vector(3 downto 0); 
begin 
if clr='0'then      ----清零
cnt0:="0000"; 
cnt1:="0000"; 
elsif clk'event and clk='1'then    ---在时钟的上升沿，
if en='1'then           ----使能端有