cout60.vhd

来自「1．6个数码管动态扫描显示驱动 2．按键模式选择(时分秒)与调整控制 3．用」· VHDL 代码 · 共 45 行

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;

ENTITY cout60 IS
PORT(en,clk: IN STD_LOGIC;
      qh,ql:OUT STD_LOGIC_VECTOR(3 DOWNTO 0);
     cout:OUT STD_LOGIC );
END cout60;

ARCHITECTURE arc OF cout60 IS
SIGNAL ah,al:STD_LOGIC_VECTOR(3 DOWNTO 0);
SIGNAL a:STD_LOGIC_VECTOR(7 DOWNTO 0);
BEGIN
qh<=ah;
ql<=al;
a<=ah&al;
  PROCESS(en,clk)
  BEGIN
    IF(clk'EVENT AND clk='1')THEN
      IF(en='1')THEN
        CASE a IS
        WHEN "00001001"|"00011001"|"00101001"|"00111001"|"01001001"=>
              al<="0000";
              ah<=ah+'1';
              cout<='0';
        WHEN "01011001"=>
              ah<="0000";
              al<="0000";
              cout<='0';
        WHEN "01011000"=>
              al<=al+'1'; 
              cout<='1';
        WHEN OTHERS=>
              al<=al+'1';
              cout<='0';
        END CASE;
      END IF;
    END IF;
  END PROCESS;
END arc;