display.vhd

maxplus2变得电子钟程序/// /// /////

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
USE IEEE.STD_LOGIC_ARITH.ALL;
ENTITY display IS
   PORT(  sclk: IN STD_LOGIC;  --scan frequency,about 1KHZ
          reset:  IN STD_LOGIC;
          trandis: OUT STD_LOGIC_VECTOR(7 DOWNTO 0);
                             --8bits for LED display
          disselect: OUT STD_LOGIC_VECTOR(2 DOWNTO 0);
                             --adress line for scanning 6 module "clock"
          hourhdis: IN INTEGER RANGE 0 TO 2;
                             --time information received from module "clock"
          hourldis: IN INTEGER RANGE 0 TO 9;
          minhdis: IN INTEGER RANGE 0 TO 5;
          minldis: IN INTEGER RANGE 0 TO 9;
          secldis: IN INTEGER RANGE 0 TO 9;
          
          sechdis: IN INTEGER RANGE 0 TO 5);
          
    PROCEDURE LEDDISP(NUMBER:INTEGER RANGE 0 TO 9) IS
             --this function will transform data to format of display
        BEGIN
           CASE NUMBER IS
              WHEN 0=>trandis<="00111111";
              WHEN 1=>trandis<="00000110";
              WHEN 2=>trandis<="01011011";
              WHEN 3=>trandis<="01001111";
              WHEN 4=>trandis<="01100110";
              WHEN 5=>trandis<="01101101";
              WHEN 6=>trandis<="01111101";
              WHEN 7=>trandis<="00000111";
              WHEN 8=>trandis<="01111111";
              WHEN 9=>trandis<="01101111";
           END CASE;
         END LEDDISP;
   END display;
 ARCHITECTURE  display_archi OF display IS 
     TYPE STATE IS (hh,hl,mh,ml,sh,sl);
                          --six states correspond to six led display
     SIGNAL nexsta,cursta: STATE;
  BEGIN 
    SCAN:
       PROCESS(sclk)
         BEGIN 
           if reset='1' then
              nexsta<=hh;
           elsif (sclk='1' and sclk'event) then
              cursta<=nexsta;
           end if;
        CASE cursta IS
            WHEN hh=>
                 disselect<="000";
                 LEDDISP(hourhdis);
                 nexsta<=hl;
            WHEN hl=>
                 disselect<="001";
                 LEDDISP(hourldis);
                 nexsta<=mh;
             WHEN mh=>
                 disselect<="010";
                 LEDDISP(minhdis);
                 nexsta<=ml;
             WHEN ml=>
                 disselect<="011";
                 LEDDISP(minldis);
                 nexsta<=sh;
             WHEN sh=>
                 disselect<="100";
                 LEDDISP(sechdis);
                 nexsta<=sl;
             WHEN sl=>
                 disselect<="101";
                 LEDDISP(secldis);
                 nexsta<=hh;
             WHEN others =>
                  null;
       END CASE;
    END PROCESS;
 END display_archi;