Forum Discussion

Honored Contributor

12 years ago

What should I use here - Need changing value in different processes

Hi, first post here and very poor VHDL knowledge. Tried my best but can't figure this out. Here is my problem:

I have 3 buttons. When any one is pressed I want to reset a corresponding variable/signal AND one (counter) or something to zero, the counter is connected to 3Hz clock. Clock works fine. Another process acts on clock ticks and increment the counter. When counter reaches a certain value the corresponding value which was set at button press gets acted upon. SO, this way I want to create a delay between button press and action (trying to avoid the debouncing and million other errors which were there before).

The problem:

I do not know which type of variable/signal to use for counter and the other corresponding value related to which button is pressed. I tried making both signals, it didn;t worked, error appeared about resolving multiple constant drivers. Tried with variable, same error.

Can some one pleaseeeeee help me?

library ieee;use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity StepperMotorController is
  port(
    stepper_clk_i    :in std_logic;
     Direction_i, Run_i, Halt_i:in std_logic;
    winding1A_o,winding1B_o,winding2A_o,winding2B_o:out std_logic;
    Led7,Led6,Led5,Led4:out std_logic;
    LED7S : OUT STD_LOGIC_VECTOR (7 DOWNTO 0)
    );
end entity StepperMotorController;
architecture structure of StepperMotorController is
    signal speed_cntrl : unsigned (1 downto 0):="00";        -- initiaize with value 0
    signal halt_cntrl, direction_cntrl: std_LOGIC:='1';
    shared variable D,R:integer:=0;
    signal clk_12Hz, clk_6Hz, clk_3Hz, stepper_clk:std_logic; -- create a 3Hz clock for 1:2:3 speed
    signal step : unsigned (2 downto 0);    -- Stes go from 0 to 7 steps = TOTAL 8 STEPS
    shared variable count:integer:=0;
    signal windings:std_logic_vector(3 downto 0);
    constant STEP1: std_logic_vector(3 downto 0):="1000"; -- for 15 degrees we need 8 steps which get repeated
    constant STEP2: std_logic_vector(3 downto 0):="1010";
    constant STEP3: std_logic_vector(3 downto 0):="0010";
    constant STEP4: std_logic_vector(3 downto 0):="0110";
    constant STEP5: std_logic_vector(3 downto 0):="0100";
    constant STEP6: std_logic_vector(3 downto 0):="0101";
    constant STEP7: std_logic_vector(3 downto 0):="0001";
    constant STEP8: std_logic_vector(3 downto 0):="1001";
begin
    winding1A_o <=windings(3);
    winding2A_o <=windings(1);
    winding1B_o <=windings(2);
    winding2B_o <=windings(0);
--    led7<=speed_cntrol(1);
--    led6<=speed_cntrol(0);
--    led7<=clk_12Hz;
--    led6<=clk_6Hz;
--    led5<=clk_3Hz;
        SPEED_BOX: process(stepper_clk_i) is
            variable counter:unsigned(2 downto 0):="000";  -- FROM 1 DOWN TO 0 > CHANGE TO 2 DOWN TO 0
            begin
                    if rising_edge(stepper_clk_i) then
                        counter:=counter+1;
                    end if;
                    clk_12Hz <= STD_LOGIC(counter(0));
                    clk_6Hz  <= STD_LOGIC(counter(1));
                    clk_3Hz  <= STD_LOGIC(counter(2));
            end process;
        
        COUNT_DELAY: process (clk_3Hz) is
            begin
                    count:=count+1;
            end process;
            
        COUNT_ACTION: process (clk_3Hz) is
            begin
                    if count=3 then
                            if D=1 then
                                direction_cntrl<=not direction_cntrl;
                            elsif R=1 then
                                speed_cntrl<=speed_cntrl+1;
                            else
                                D:=0;
                                R:=0;
                            end if;
                    end if;
            end process;
            
        SPEED_SELECT: with speed_cntrl select
                        stepper_clk <=    clk_12Hz when "00", 
                                           clk_6Hz  when "01",
                                           clk_3Hz  when others;-- on 2 it will get 3Hz.
        SPEED_DISPLAY: process (halt_cntrl,speed_cntrl) IS
            begin
                    if halt_cntrl='1' then
                                LED7S <=not "01110110"; -- 'H'
                    elsif speed_cntrl="00" then
                                LED7S<= not "01001110";    --'F'
                    elsif speed_cntrl="01" then
                                LED7S<=    not "00111110";--'|-|
                    else
                                LED7S<=    not "01101101";-- 'S'
                    end if;             -----.gfedcba 1low - 0 - high
            end process;
        STEPPER_SEQUENCER: process(stepper_clk) is  
            begin
                    if rising_edge(stepper_clk) then
                        if halt_cntrl='0' then
                            if direction_cntrl='1' then 
                                step <= step+1;
                            else
                                step <= step-1;
                            end if;
                        end if;
                    end if;
            end process;
 
        COIL_DRIVER: with step select
                                    windings <= STEP1  when "000",
                                                    STEP2  when "001",
                                                    STEP3  when "010",
                                                    STEP4  when "011",
                                                    STEP5  when "100",
                                                    STEP6  when "101",
                                                    STEP7  when "110",
                                                    STEP8  when "111",
                                                  "0000" when others;
        
        CONTROL: process(Direction_i,Run_i,Halt_i) is
            begin
                    if Direction_i='1' then
                        if halt_cntrl='0' then
                            count:=0;
                            D:=1;
                        end if;
                    elsif (Run_i='1') then
                        if halt_cntrl='1' then
                                halt_cntrl<='0';
                        else
                            count:=0;
                            R:=1;
                        end if;
                    elsif (Halt_i='1')     then
                            halt_cntrl<='1';
                    end if;
            end process CONTROL;
END structure;

18 Replies

Altera_Forum
Honored Contributor
12 years ago
Plenty of errors, for now I suggest:
those three assignments underneath [counter := counter + 1;] should be outside process
process for count needs clock edge
values of count, D,R should be settled each in its process
Altera_Forum
Honored Contributor
12 years ago
And as a beginner - avoid variables. They are updated immediatly and may not produce the hardware you expect as assignment ordering becomes important in the code. There is nothing you can do with a variable you cant do with a signal (for synthesisable logic anyway), so stick with signals only.
Altera_Forum
Honored Contributor
12 years ago
Oh, and while we;re at it -0 generating clocks from counters is very bad practice. The thing to do is use clock enables instead and clock everything with the system clock.

Altera_Forum

Honored Contributor

12 years ago

--- Quote Start ---

Plenty of errors, for now I suggest:

those three assignments underneath [counter := counter + 1;] should be outside process

process for count needs clock edge

values of count, D,R should be settled each in its process

--- Quote End ---

Thanks. Did the above.

1) Variable counter changed to shared variable outside the process and declared there.

2) statements assigning clock12/6/3 to counter are put outside the process.

3) No idea of how to implement 3.

architecture structure of StepperMotorController is
	signal speed_cntrl : unsigned (1 downto 0):="00";		-- initiaize with value 0
	signal halt_cntrl, direction_cntrl: std_LOGIC:='1';
	shared variable D,R:integer:=0;
	shared variable counter:unsigned(2 downto 0):="000";  -- FROM 1 DOWN TO 0 > CHANGE TO 2 DOWN TO 0
	signal clk_12Hz, clk_6Hz, clk_3Hz, stepper_clk:std_logic; -- create a 3Hz clock for 1:2:3 speed
	signal step : unsigned (2 downto 0);	-- Stes go from 0 to 7 steps = TOTAL 8 STEPS
	shared variable count:integer:=0;
	signal windings:std_logic_vector(3 downto 0);
	constant STEP1: std_logic_vector(3 downto 0):="1000"; -- for 15 degrees we need 8 steps which get repeated
	constant STEP2: std_logic_vector(3 downto 0):="1010";
	constant STEP3: std_logic_vector(3 downto 0):="0010";
	constant STEP4: std_logic_vector(3 downto 0):="0110";
	constant STEP5: std_logic_vector(3 downto 0):="0100";
	constant STEP6: std_logic_vector(3 downto 0):="0101";
	constant STEP7: std_logic_vector(3 downto 0):="0001";
	constant STEP8: std_logic_vector(3 downto 0):="1001";
begin
	winding1A_o <=windings(3);
	winding2A_o <=windings(1);
	winding1B_o <=windings(2);
	winding2B_o <=windings(0);
	clk_12Hz <= STD_LOGIC(counter(0));
	clk_6Hz  <= STD_LOGIC(counter(1));
	clk_3Hz  <= STD_LOGIC(counter(2));
					
--	led7<=speed_cntrol(1);
--	led6<=speed_cntrol(0);
--	led7<=clk_12Hz;
--	led6<=clk_6Hz;
--	led5<=clk_3Hz;
		SPEED_BOX: process(stepper_clk_i) is
			begin
					if rising_edge(stepper_clk_i) then
						counter:=counter+1;
					end if;
			end process;
		
		COUNT_DELAY: process (clk_3Hz) is
			begin
					count:=count+1;
			end process;
.
.
.
.
.
.
.

Altera_Forum
Honored Contributor
12 years ago
Thanks Tricky. I missed your reply earlier. My professor wrote the whole code (not my fav. professor by the way). We are not taught the basics, just the difference between signals and variables. I am struggling quiet a lot with this - (suppose to be a simple task). Any help with the code will be much appreciated.

Altera_Forum

Honored Contributor

12 years ago

 -- for guidance
signal counter : unsigned(2 downto 0) := "000";
signal count : integer range 0 to ... := 0;
...
process(stepper_clk_in)
begin
if rising_edge(stepper_clk_in) then
    counter <= counter+1;   -- 0 ~ 7
end if;
end process;
clk_12 <= std_logic(counter(0));
clk_6   <= std_logic(counter(1));
clk_3   <= std_logic(counter(2));
process(stepper_in_clk)
begin
if rising_edge(stepper_in_clk) then
     if clk_12 = '1' then
         if count = ? then
             count <= ?;
        elsif direction_i = '0' and run_i = '1' and halt_ctrl = '0' then
             count <= 0;
        else
             count <= count + 1; 
       end if;
     end if;
end if;
end process;

Altera_Forum
Honored Contributor
12 years ago
--- Quote Start ---
My professor wrote the whole code (not my fav. professor by the way). We are not taught the basics, just the difference between signals and variables.
--- Quote End ---

if he is underpaid then understandable; else put him against the wall and shoot; end if;

Altera_Forum

Honored Contributor

12 years ago

Here is my new code:

library ieee;use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity StepperMotorController is
  port(
    stepper_clk_i    :in std_logic;
	 Direction_i, Run_i, Halt_i:in std_logic;
    winding1A_o,winding1B_o,winding2A_o,winding2B_o:out std_logic;
    Led7,Led6,Led5,Led4:out std_logic;
    LED7S : OUT STD_LOGIC_VECTOR (7 DOWNTO 0)
	);
end entity StepperMotorController;
architecture structure of StepperMotorController is
	signal speed_cntrl : unsigned (1 downto 0):="00";		-- initiaize with value 0
	signal halt_cntrl, direction_cntrl: std_LOGIC:='1';
	signal D,R,H,Done:std_LOGIC:='0';
	signal counter:unsigned(2 downto 0):="000";  -- FROM 1 DOWN TO 0 > CHANGE TO 2 DOWN TO 0
	signal clk_12Hz, clk_6Hz, clk_3Hz, stepper_clk:std_logic; -- create a 3Hz clock for 1:2:3 speed
	signal step : unsigned (2 downto 0);	-- Stes go from 0 to 7 steps = TOTAL 8 STEPS
	signal count:integer range 0 to 10:=0;
	signal windings:std_logic_vector(3 downto 0);
	constant STEP1: std_logic_vector(3 downto 0):="1000"; -- for 15 degrees we need 8 steps which get repeated
	constant STEP2: std_logic_vector(3 downto 0):="1010";
	constant STEP3: std_logic_vector(3 downto 0):="0010";
	constant STEP4: std_logic_vector(3 downto 0):="0110";
	constant STEP5: std_logic_vector(3 downto 0):="0100";
	constant STEP6: std_logic_vector(3 downto 0):="0101";
	constant STEP7: std_logic_vector(3 downto 0):="0001";
	constant STEP8: std_logic_vector(3 downto 0):="1001";
begin
	winding1A_o <=windings(3);
	winding2A_o <=windings(1);
	winding1B_o <=windings(2);
	winding2B_o <=windings(0);
	clk_12Hz <= STD_LOGIC(counter(0));
	clk_6Hz  <= STD_LOGIC(counter(1));
	clk_3Hz  <= STD_LOGIC(counter(2));
					
--	led7<=speed_cntrol(1);
--	led6<=speed_cntrol(0);
--	led7<=clk_12Hz;
--	led6<=clk_6Hz;
--	led5<=clk_3Hz;
		SPEED_BOX: process(stepper_clk_i) is
			begin
					if rising_edge(stepper_clk_i) then
						counter<=counter+1;
					end if;
			end process;
		
		SPEED_SELECT: with speed_cntrl select
						stepper_clk <=	clk_12Hz when "00", 
										   clk_6Hz  when "01",
										   clk_3Hz  when others;-- on 2 it will get 3Hz.
		SPEED_DISPLAY: process (halt_cntrl,speed_cntrl) IS
			begin
					if halt_cntrl='1' then
								LED7S <=not "01110110"; -- 'H'
					elsif speed_cntrl="00" then
								LED7S<= not "01001110";	--'F'
					elsif speed_cntrl="01" then
								LED7S<=	not "00111110";--'|-|
					else
								LED7S<=	not "01101101";-- 'S'
					end if;	         -----.gfedcba 1low - 0 - high
			end process;
		STEPPER_SEQUENCER: process(stepper_clk) is  
			begin
					if rising_edge(stepper_clk) then
						if halt_cntrl='0' then
							if direction_cntrl='1' then 
								step <= step+1;
							else
								step <= step-1;
							end if;
						end if;
					end if;
			end process;
 
		COIL_DRIVER: with step select
									windings <= STEP1  when "000",
													STEP2  when "001",
													STEP3  when "010",
													STEP4  when "011",
													STEP5  when "100",
													STEP6  when "101",
													STEP7  when "110",
													STEP8  when "111",
												  "0000" when others;
		
		CONTROL: process(stepper_clk_i) is
			begin
				if rising_edge(stepper_clk_i) then
					if rising_edge(clk_6Hz) then
							if count=9 then
								count<=1;
							elsif Direction_i='1' and halt_cntrl='0' then
									count<=0;
									D<='1';
							elsif Run_i='1' and halt_cntrl='0' then
									count<=0;
									R<='1';
							elsif Halt_i<='1' then
									count<=0;
									H<='1';
							else
									if Done='1' then
										if D='1' OR R='1' OR H='1' then
											D<='0';
											R<='0';
											H<='0';
										end if;
									end if;
									count<=count+1;
							end if;
					end if;
				end if;
			end process CONTROL;
			ACTION: process (stepper_clk_i) is
				begin
						if count>5 then
							if D='1' then
										direction_cntrl<=not direction_cntrl;
										Done<='1';
							elsif R='1' then
										if halt_cntrl='1' then
											halt_cntrl<='0';
											Done<='1';
										else
											speed_cntrl<=speed_cntrl+1;
											Done<='1';
										end if;
							elsif H='1' then
										Halt_cntrl<='1';
										Done<='1';
							else
										Done<='0';
							end if;
						END IF;
				end process;
END structure;

new error: error (10821): hdl error at steppermotorcontroller.vhd(100): can't infer register for "d" because its behavior does not match any supported register model

same error goes for h,r and count signal.

Altera_Forum
Honored Contributor
12 years ago
you cannot clock a register from 2 sources, and you especially cannot clock a register when another clock is fired. having:

if rising_edge(clk1) then if rising_edge(clk2) then

is impossible - think about it. You're asking to detect a rising edge that is exactly co-incident with another rising edge. I think what you mean is:

if rising_edge(stepper_clk_i) then if clk_6Hz = '1' then --clock enable coding

Altera_Forum

Honored Contributor

12 years ago

This is the final code upto now:

library ieee;use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity StepperMotorController is
  port(
    stepper_clk_i    :in std_logic;
	 Direction_i, Run_i, Halt_i:in std_logic;
    winding1A_o,winding1B_o,winding2A_o,winding2B_o:out std_logic;
    Led7,Led6,Led5,Led4:out std_logic;
    LED7S : OUT STD_LOGIC_VECTOR (7 DOWNTO 0)
	);
end entity StepperMotorController;
architecture structure of StepperMotorController is
	signal speed_cntrl : unsigned (1 downto 0):="01";		-- initiaize with value 0
	signal halt_cntrl, direction_cntrl: std_LOGIC:='1';
	signal D,R,H,Done:std_LOGIC:='0';
	signal counter:unsigned(2 downto 0):="000";  -- FROM 1 DOWN TO 0 > CHANGE TO 2 DOWN TO 0
	signal clk_12Hz, clk_6Hz, clk_3Hz, stepper_clk:std_logic; -- create a 3Hz clock for 1:2:3 speed
	signal step : unsigned (2 downto 0);	-- Stes go from 0 to 7 steps = TOTAL 8 STEPS
	signal count:integer range 0 to 10:=0;
	signal windings:std_logic_vector(3 downto 0);
	constant STEP1: std_logic_vector(3 downto 0):="1000"; -- for 15 degrees we need 8 steps which get repeated
	constant STEP2: std_logic_vector(3 downto 0):="1010";
	constant STEP3: std_logic_vector(3 downto 0):="0010";
	constant STEP4: std_logic_vector(3 downto 0):="0110";
	constant STEP5: std_logic_vector(3 downto 0):="0100";
	constant STEP6: std_logic_vector(3 downto 0):="0101";
	constant STEP7: std_logic_vector(3 downto 0):="0001";
	constant STEP8: std_logic_vector(3 downto 0):="1001";
begin
	winding1A_o <=windings(3);
	winding2A_o <=windings(1);
	winding1B_o <=windings(2);
	winding2B_o <=windings(0);
	clk_12Hz <= STD_LOGIC(counter(0));
	clk_6Hz  <= STD_LOGIC(counter(1));
	clk_3Hz  <= STD_LOGIC(counter(2));
					
--	led7<=speed_cntrol(1);
--	led6<=speed_cntrol(0);
--	led7<=clk_12Hz;
--	led6<=clk_6Hz;
--	led5<=clk_3Hz;
		SPEED_BOX: process(stepper_clk_i) is
			begin
					if rising_edge(stepper_clk_i) then
						counter<=counter+1;
					end if;
			end process;
		
		SPEED_SELECT: with speed_cntrl select
						stepper_clk <=	clk_12Hz when "00", 
										   clk_6Hz  when "01",
										   clk_3Hz  when others;-- on 2 it will get 3Hz.
		SPEED_DISPLAY: process (halt_cntrl,speed_cntrl) IS
			begin
					if halt_cntrl='1' then
								LED7S <=not "01110110"; -- 'H'
					elsif speed_cntrl="00" then
								LED7S<= not "01001110";	--'F'
					elsif speed_cntrl="01" then
								LED7S<=	not "00111110";--'|-|
					else
								LED7S<=	not "01101101";-- 'S'
					end if;	         -----.gfedcba 1low - 0 - high
			end process;
		STEPPER_SEQUENCER: process(stepper_clk) is  
			begin
					if rising_edge(stepper_clk) then
						if halt_cntrl='0' then
							if direction_cntrl='1' then 
								step <= step+1;
							else
								step <= step-1;
							end if;
						end if;
					end if;
			end process;
 
		COIL_DRIVER: with step select
									windings <= STEP1  when "000",
													STEP2  when "001",
													STEP3  when "010",
													STEP4  when "011",
													STEP5  when "100",
													STEP6  when "101",
													STEP7  when "110",
													STEP8  when "111",
												  "0000" when others;
		
		CONTROL: process(clk_6Hz,Direction_i,halt_i,run_i) is
			begin
--				if rising_edge(stepper_clk_i) then
--					if (clk_12Hz='1') then
							if count=9 then
								count<=1;
							elsif Direction_i='1' and halt_cntrl='0' then
									count<=0;
									D<='1';
							elsif Run_i='1' and halt_cntrl='0' then
									count<=0;
									R<='1';
							elsif Halt_i<='1' then
									count<=0;
									H<='1';
							else
									if Done='1' then
										if D='1' OR R='1' OR H='1' then
											D<='0';
											R<='0';
											H<='0';
										end if;
									end if;
									count<=count+1;
							end if;
--					end if;
--				end if;
			end process CONTROL;
			
			ACTION: process (stepper_clk_i) is
				begin
						if count=3 then
							if D='1' then
										direction_cntrl<=not direction_cntrl;
										Done<='1';
							elsif R='1' then
										if halt_cntrl='1' then
											halt_cntrl<='0';
											Done<='1';
										else
											speed_cntrl<=speed_cntrl+1;
											Done<='1';
										end if;
							elsif H='1' then
										Halt_cntrl<='1';
										Done<='1';
							else
										Done<='0';
							end if;
						END IF;
				end process;
END structure;

BUT it is not responding to any inputs (Direction_i/Halt_i/Run_i).

Forum Discussion

What should I use here - Need changing value in different processes

18 Replies

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