reset.vhd

来自「此为用VHDL编写的可实现动感图像的点阵」· VHDL 代码 · 共 34 行

library ieee;
use  ieee.std_logic_1164.all;
use  ieee.std_logic_signed.all;
entity reset  is
      port(
            clk:in std_logic;
            key: in std_logic;
            cpo:  out std_logic);
end reset ;
architecture  behavor  of reset  is
      signal cp:std_logic;
      signal jsp:integer  range 0 to 5;
          begin
process(clk)
      begin
 if(clk'event and clk='1')then
       if(key='1') then
              if jsp=5  then
                jsp<=jsp;
              else
                 jsp<=jsp+1;
              end if;
           end if;
       if (jsp>=4 and key='0' ) then
              cp<='1';jsp<=0;
          else
               cp<='0';
        end if;
end if;
cpo<=cp;
end process;
end behavor;