counter10.vhd

这是一个实现时分秒的时钟功能的源码

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
entity counter10 is
    port(clk:in std_logic;
         reset:in std_logic;
         din:in std_logic_vector(3 downto 0);
         dout:out std_logic_vector(3 downto 0);
         c:out std_logic);
end counter10;

architecture Behavioral of counter10 is
    signal count:std_logic_vector(3 downto 0);
begin
    dout<=count;
process(clk,reset,din)
begin
     if reset='0' then
         count<=din;
         c<='0';
     elsif rising_edge(clk) then
         if count="1001" then
             count<="0000";
             c<='1';
         else
             count<=count+1;
             c<='0';
         end if;
       end if;
end process;
end Behavioral;