wdisplay3.vhd

点阵显示的vhdl程序,是一个学员实验用的程序

------字符显示部分
LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;

ENTITY wdisplay3 IS 
PORT (
   CLK : IN STD_LOGIC;   -----控制了扫描的频率
   ROW  :OUT STD_LOGIC_VECTOR(7 DOWNTO 0);  ----选择列中发光的二极管
   COL  :OUT STD_LOGIC_VECTOR(7 DOWNTO 0)  ----选择发光的阵列
);
END wdisplay3;

ARCHITECTURE BEHV OF wdisplay3 IS  
SIGNAL CNT : STD_LOGIC_VECTOR(2 DOWNTO 0);
BEGIN 
  PROCESS(CLK)
    BEGIN
      IF RISING_EDGE(CLK) THEN 
          CNT<=CNT+1;
      END IF;
  END PROCESS;
COL<= "10000000" WHEN CNT="000"   ELSE 
       "01000000" WHEN CNT="001"   ELSE
       "00100000" WHEN CNT="010"    ELSE
       "00010000" WHEN CNT="011"  ELSE
       "00001000" WHEN CNT="100"  ELSE
       "00000100" WHEN CNT="101"   ELSE
       "00000010" WHEN CNT="110"   ELSE
       "00000001" ;
ROW<= "11111100" WHEN CNT="000" ELSE
       "10000010" WHEN CNT="001" ELSE
       "10000010" WHEN CNT="010" ELSE
       "10000010" WHEN CNT="011" ELSE
       "10000010" WHEN CNT="100" ELSE
       "10000010" WHEN CNT="101" ELSE
       "10000010" WHEN CNT="110" ELSE
       "11111100" ; 
END BEHV;