Modify VHDL code of the stepper motor on page 603 of your te

Modify VHDL code of the stepper motor on page 603 of your textbook without the last 5 lines starting with the \"with state select ...\", see below: vhdl entity stepper a Explain why the stepper motor requires a special count of 3, 6, 12, 9 then repeat to work.

Solution

a) VHDL code for Stepper Mottor
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

-- Uncomment the following lines to use the declarations that are
-- provided for instantiating Xilinx primitive components.
--library UNISIM;
--use UNISIM.VComponents.all;

entity stepper is
Port ( clk,dir : in std_logic;
Q : out std_logic_vector(3 downto 0));
end stepper;

architecture Behavioral of stepper is
           TYPE state_type is (three,six,nine,twelve);
           SIGNAL state:state_type;
begin
  
   stepper:   process(clk,dir) is
   begin
   if rising_edge (clk) then
   if dir =\'1\' then
           CASE state IS

when nine =>
               state <= twelve;
               Q <=\"1001\";

               when twelve =>
               state <= six;
               Q <=\"1100\";

               when six =>
               state <= three;
               Q <=\"0110\";

when three =>
               state <= nine;
               Q <=\"0011\";
           end CASE;
           else
           CASE state IS
               when three =>
               state <= six;
               Q <=\"0011\";
               when six =>
               state <= twelve;
               Q <=\"0110\";

               when twelve =>
               state <= nine;
               Q <=\"1100\";

               when nine=>
               state <= three;
               Q <=\"1001\";
           end CASE;
       end if ;
   end if;
end process stepper;

end Behavioral;

b) the steps at which Stepper motor rotates is 3,6,9,12 because it is running at full step sequence

in the full step sequence two coils are energized at the same time and moter shaft rotates.the order in which they rorate is given below.

step 1: 1001

step2: 1100

step3: 0110

step4: 0011

the above order is for direction forward(dir=1).