原创 【转】VHDL设计举例：步进电机控制器

LIBRARY IEEE;

USE IEEE.std_logic_1164.ALL;

USE IEEE.std_logic_unsigned.ALL;

USE IEEE.std_logic_arith.ALL;

ENTITY step_motor IS

     PORT(

         f, p, d: IN   STD_LOGIC:='0';

         speed : in  STD_LOGIC_VECTOR(1 downto 0);

         coil : OUT    STD_LOGIC_VECTOR(3 downto 0)

         );

END step_motor;

ARCHITECTURE behavior OF step_motor IS

     SIGNAL ind_coil: STD_LOGIC_VECTOR(3 downto 0) := "0001";

     SIGNAL clk_scan: STD_LOGIC;

    SIGNAL PHASE,DIRECTION:STD_LOGIC;

    signal t:std_logic_vector(3 downto 0);

     signal comp:integer range 0 to 2500 ;

    SIGNAL osc:STD_LOGIC;

     BEGIN

coil <= t;

process(f,osc)

variable delay:integer range 0 to 50;

begin

if (f'event and f='1') then

 if delay>=50 then delay:=0;osc<=not osc;

 else delay:=delay+1;

end if;

end if;

if (osc'event and osc='1') then

case speed is

   when "10" => if comp<2500 then comp<=comp+1;

                else comp<=comp;

                end if;

   when "01" => if comp>2 then comp<=comp-1;

                else comp<=comp;

                end if;

   when others => if comp<2 then comp<=2;

                else comp<=comp;

                end if;

end case;

end if;

end process;

PROCESS

     VARIABLE d_ff: integer range 0 to 2500;

BEGIN

     WAIT UNTIL f = '1';

     if d_ff >= comp then

         d_ff :=0; clk_scan <= not CLK_SCAN;

     else

         d_ff := d_ff + 1;

     end if;

          END PROCESS ;

 PROCESS(F)

 VARIABLE B:STD_LOGIC;

 BEGIN

 IF (F'EVENT AND F='1') THEN B:=(P and (b and P) );

 IF B='1' THEN PHASE<=NOT PHASE ;B:='0';

 ELSIF P='0' THEN PHASE<=PHASE;B:='1';

 END IF;

 END IF;

 END PROCESS;

 PROCESS(F)

 VARIABLE B:STD_LOGIC;

 BEGIN

 IF (F'EVENT AND F='1') THEN B:=(D and (b and D) );

 IF B='1' THEN DIRECTION<=NOT DIRECTION ;B:='0';

 ELSIF D='0' THEN DIRECTION<=DIRECTION;B:='1';

 END IF;

 END IF;

 END PROCESS;

motor:

process

begin

--if (clk_scan'event and clk_scan='1') then

WAIT UNTIL clk_scan= '0';

     CASE phase IS

         WHEN '1' =>

             IF direction = '0' THEN

                 IF ((ind_coil = "1001") or (ind_coil = "0000")) THEN

                  ind_coil <= "0001";

                 ELSE

                  ind_coil <= (ind_coil(2 downto 0) & ind_coil(3));

             END IF;

             ELSE

                 IF ((ind_coil = "1001") or (ind_coil = "0000")) THEN

                 ind_coil <= "1000";

                 ELSE

                  ind_coil <= (ind_coil(0) & ind_coil(3 downto 1));

             END IF;

             END IF;

           WHEN OTHERS =>

                         ind_coil<=IND_COIL;

           END CASE;

t<=not ind_coil;

END PROCESS motor;

END behavior;