VHDL Stepper Motor Control

Hello all!

I have to control a stepper motor for only 180 degrees range in vhdl. When i coded for the following

0 1 0 1 0.0°
1 0 0 1 7.5°
1 0 1 0 15.0°
0 1 1 0 22.5°
0 1 0 1 30.0°
1 0 0 1 37.5°
1 0 1 0 45.0°
0 1 1 0 52.5°
0 1 0 1 60.0°
1 0 0 1 67.5°
1 0 1 0 75.0°
0 1 1 0 82.5°
0 1 0 1 90.0°
1 0 0 1 97.5°
1 0 1 0 105.0°
0 1 1 0 112.5°
0 1 0 1 120.0°
1 0 0 1 127.5°
1 0 1 0 135.0°
0 1 1 0 142.5°
0 1 0 1 150.0°
1 0 0 1 157.5°
1 0 1 0 165.0°
0 1 1 0 172.5°

with 18 states, its still rotating for complete 360deg.

can you please help me out in my logical errors in the following pgm


architecture rtl of stepper_motor is

type my_state is(idle,state0,state1,state2,state3);--,state4,state5,state6,state7,state8,state9,state10,state11,state12,state13,state14,state15,state16,state17,state18
signal present_state,next_state :my_state;

begin
process(rst,clk,en)
begin
if(rst = '1' and en='0') then
present_state <= idle;
elsif(clk='1' and clk'event and en='1') then
present_state <= next_state;
end if;
end process;
--
--process(present_state,direction,en)
--begin
--case(present_state) is
--
--when idle =>
-- next_state <= state0;
--
--when state0 =>
-- if(direction='0'and en='1') then
-- dout <= "1001";
-- next_state <= state1;
-- elsif(direction='1') then
-- dout <= "0101";
-- elsif(en='0') then
-- next_state <= present_state;
-- end if;
--
--when state1 =>
-- if(direction='0' and en='1') then
-- dout <= "1010";
-- next_state <= state2;
-- elsif(direction='1' and en='1') then
-- next_state <= state0;
-- elsif(en='0') then
-- next_state <= present_state;
-- end if;
--
--when state2 =>
-- if(direction='0'and en='1') then
-- dout <= "0110";
-- next_state <= state3;
-- elsif(direction='1'and en='1') then
-- next_state <= state1;
-- elsif(en='0') then
-- next_state <= present_state;
-- end if;
--
--when state3 =>
-- if(direction='0'and en='1') then
-- dout <= "0101";
-- next_state <= state4;
-- elsif(direction='1'and en='1') then
-- next_state <= state2;
--
-- elsif(en='0') then
-- next_state <=state3;
-- end if;
--when state4 =>
-- if(direction='0'and en='1') then
-- dout <= "1001";
-- next_state <= state0;
-- elsif(direction='1'and en='1') then
-- next_state <= state3;
-- elsif(en='0') then
-- next_state <=present_state;
-- end if;
--
----
----when state5 =>
---- if(direction='0'and en='1') then
---- dout <= "0110";
---- next_state <= state6;
---- elsif(direction='1'and en='1') then
---- next_state <= state4;
---- elsif(en='0') then
---- next_state <=present_state;
---- end if;
----
----
----when state6 =>
---- if(direction='0'and en='1') then
---- dout <= "0101";
---- next_state <= state7;
---- elsif(direction='1'and en='1') then
---- next_state <= state5;
---- elsif(en='0') then
---- next_state <=present_state;
---- end if;
----
----
----when state7 =>
---- if(direction='0'and en='1') then
---- dout <= "1001";
---- next_state <= state8;
---- elsif(direction='1'and en='1') then
---- next_state <= state6;
---- elsif(en='0') then
---- next_state <=present_state;
---- end if;
----
----
----when state8 =>
---- if(direction='0'and en='1') then
---- dout <= "0110";
---- next_state <= state9;
---- elsif(direction='1'and en='1') then
---- next_state <= state7;
---- elsif(en='0') then
---- next_state <=present_state;
---- end if;
----
----
----when state9 =>
---- if(direction='0'and en='1') then
---- dout <= "0101";
---- next_state <= state10;
---- elsif(direction='1'and en='1') then
---- next_state <= state8;
---- elsif(en='0') then
---- next_state <=present_state;
---- end if;
----
----
----when state10 =>
---- if(direction='0'and en='1') then
---- dout <= "1001";
---- next_state <= state11;
---- elsif(direction='1'and en='1') then
---- next_state <= state9;
---- elsif(en='0') then
---- next_state <=present_state;
---- end if;
----
----
----when state11 =>
---- if(direction='0'and en='1') then
---- dout <= "0110";
---- next_state <= state12;
---- elsif(direction='1'and en='1') then
---- next_state <= state10;
---- elsif(en='0') then
---- next_state <=present_state;
---- end if;
----
----
----when state12 =>
---- if(direction='0'and en='1') then
---- dout <= "0101";
---- next_state <= state13;
---- elsif(direction='1'and en='1') then
---- next_state <= state11;
---- elsif(en='0') then
---- next_state <=present_state;
---- end if;
----
----
----when state13 =>
---- if(direction='0'and en='1') then
---- dout <= "1001";
---- next_state <= state14;
---- elsif(direction='1'and en='1') then
---- next_state <= state12;
---- elsif(en='0') then
---- next_state <=present_state;
---- end if;
----
----
----when state14 =>
---- if(direction='0'and en='1') then
---- dout <= "0110";
---- next_state <= state15;
---- elsif(direction='1'and en='1') then
---- next_state <= state13;
---- elsif(en='0') then
---- next_state <=present_state;
---- end if;
----
----
----when state15 =>
---- if(direction='0'and en='1') then
---- dout <= "0101";
---- next_state <= state16;
---- elsif(direction='1'and en='1') then
---- next_state <= state14;
---- elsif(en='0') then
---- next_state <=present_state;
---- end if;
----
----
----when state16 =>
---- if(direction='0'and en='1') then
---- dout <= "1001";
---- next_state <= state17;
---- elsif(direction='1'and en='1') then
---- next_state <= state15;
---- elsif(en='0') then
---- next_state <=present_state;
---- end if;
----
----
----when state17 =>
---- if(direction='0'and en='1') then
---- dout <= "0110";
---- next_state <= state18;
---- elsif(direction='1'and en='1') then
---- next_state <= state16;
---- elsif(en='0') then
---- next_state <=present_state;
---- end if;
----
----
----when state18 =>
---- if(direction='0'and en='1') then
---- dout <= "0101";
---- next_state <= idle;
---- elsif(direction='1'and en='1') then
---- next_state <= state17;
---- elsif(en='0') then
---- next_state <=present_state;
---- end if;
--
--
--end case;
--end process;
--end rtl;
--

process(present_state,direction)
begin

case(present_state) is

when idle =>
if(en='0') then
next_state<=present_state;
else next_state <= state0;
end if;


when state0 =>
dout <= "0101";
next_state <= state1;

when state1 =>
if(direction='0') then
dout <= "1001";
elsif(direction='1') then
dout <= "0110";
end if;
next_state <= state2;

when state2 =>
dout <= "1010";
next_state <= state3;

when state3 =>
if(direction='0') then
dout <= "0110";
elsif(direction='1') then
dout <= "1001";
end if;
next_state <= state0;
end case;
end process;
end rtl;

Actually, i want my stepper motor to rotate when i give enable signal and stop rotating if enable is 0. Moreover, the stepper motor should move only from 0-180degrees and should stop still in the current position if i dont give enable signal...

I would be grateful for any kind of help in this.

Regards
Raguna

Moved as new thread in PLD, SPLD, GAL, CPLD, FPGA Design section [alexan_e]

Click to expand...

Re: Stepper Motor Control

@ Raguna:
Sorry, but what is ur terminals order? A B A* B* or what?
But firstly I think to get the 7.5 deg, it is a half step
and u r applying full step sequence