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Implementation of State Machine in Vhdl

Mar 24

Yazan: 

Hi everyone,

Today i will show you how to create a state machine and implementation of that. 
Most important thing in designing at state machine is that lines.
type state_type is (zero, one, two, three, four, five, six, seven, eight, nine);
signal state : state_type;

My state are from zero to nine.
After the implementing this code you can get the state diagram.

library ieee;
use ieee.std_logic_1164.all;

entity BCD_counter is
generic(N : integer := 4);
port
(
clk         : in    std_logic;
reset        : in    std_logic;
y     : inout std_logic_vector((N-1) downto 0);
segment1: out std_logic_vector (6 downto 0)    );

end entity;

architecture bevahioral of BCD_counter is

type state_type is (zero, one, two, three, four, five, six, seven, eight, nine);
signal state : state_type;
signal temp : std_logic_vector ((N-1) downto 0);

begin

process (clk, reset)
begin

if reset = '1' then
state <= zero ;
temp <= "0000";

elsif (rising_edge(clk)) then

case state is

when zero =>
temp <= "0000";
state <= one;

when one =>
temp <= "0001";
state <= two;

when two =>
temp <= "0010";
state <= three;

when three =>
temp <= "0011";
state <=four ;

when four =>
temp <= "0100";
state <=five ;

when five =>
temp <= "0101";
state <=six ;

when six =>
temp <= "0110";
state <=seven ;

when seven =>
temp <= "0111";
state <=eight ;

when eight =>
temp <= "1000";
state <=nine ;

when others =>
temp <="1001";
state <=zero ;

end case;

end if;
end process;

y <= temp;

process(y)
begin
case y is
when "0000" => segment1 <= "1000000";
when "0001" => segment1 <= "1001111";
when "0010" => segment1 <= "0100100";
when "0011" => segment1 <= "0110000";
when "0100" => segment1 <= "0011001";
when "0101" => segment1 <= "0100100";
when "0110" => segment1 <= "0000010";
when "0111" => segment1 <= "0111000";
when "1000" => segment1 <= "0000000";
when "1001" => segment1 <= "0011000";
when "1010" => segment1 <= "0100000";
when "1011" => segment1 <= "0000011";
when "1100" => segment1 <= "1000110";
when "1101" => segment1 <= "0100001";
when "1110" => segment1 <= "0000110";
when others => segment1 <= "0001110";
end case;

end process;

end bevahioral;
--ozturkgokhan.com

After implementing the code use this path to get state machine diagram “Tools>Netlist Viewers> State Machine Viewer”

BCD_counter_state

State Machine Diagram

 

sinyaller

Modelsim Output

best wishes,
gökhan öztürk

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BCD Upcounter with Seven Segment display

Mar 23

Yazan: 

Hi everyone,
today we will learn how to use seven segment display and usage of case-when. 
At my one of the earlier post i did counter but now i improved the program. 
Now it counts from "0000" to "1001" then it goes back.

I have a reset input as you see and at the end of the program there are two when-case 
situation. These are fır the seven segment displays at Cyclone V SoC 5CSEMA5F31 board.
library ieee;
use ieee.std_logic_1164.all;
use IEEE.STD_LOGIC_ARITH.ALL;
use ieee.std_logic_unsigned.all;

entity BCD_counter is
generic (N : integer:= 3 );
port( clk : in std_logic;
rst : in std_logic;
y   : out std_logic_vector(3 downto 0) );
end entity;

architecture behavioral of BCD_counter is

signal ara : std_logic_vector(3 downto 0);

begin

process(clk,rst)

begin
if rst = '1' then
ara <= "0000";
--    elsif ara = "1010" then
--    ara <= "0000";
elsif rising_edge(clk) then
ara <= ara + "0001" ;
else
ara <= ara;
end if;
end process;
y <= ara;
process(y)
begin
case y(3 downto 0) is
when "0000" => segment1 <= "1000000";
when "0001" => segment1 <= "1001111";
when "0010" => segment1 <= "0100100";
when "0011" => segment1 <= "0110000";
when "0100" => segment1 <= "0011001";
when "0101" => segment1 <= "0100100";
when "0110" => segment1 <= "0000010";
when "0111" => segment1 <= "0111000";
when "1000" => segment1 <= "0000000";
when "1001" => segment1 <= "0011000";
when "1010" => segment1 <= "0100000";
when "1011" => segment1 <= "0000011";
when "1100" => segment1 <= "1000110";
when "1101" => segment1 <= "0100001";
when "1110" => segment1 <= "0000110";
when others => segment1 <= "0001110";
end case;

case y(7 downto 4) is
when "0000" => segment2 <= "1000000";
when "0001" => segment2 <= "1001111";
when "0010" => segment2 <= "0100100";
when "0011" => segment2 <= "0110000";
when "0100" => segment2 <= "0011001";
when "0101" => segment2 <= "0100100";
when "0110" => segment2 <= "0000010";
when "0111" => segment2 <= "0111000";
when "1000" => segment2 <= "0000000";
when "1001" => segment2 <= "0011000";
when "1010" => segment2 <= "0100000";
when "1011" => segment2 <= "0000011";
when "1100" => segment2 <= "1000110";
when "1101" => segment2 <= "0100001";
when "1110" => segment2 <= "0000110";
when others => segment2 <= "0001110";
end case;

end process;
end behavioral;
--ozturkgokhan.com
s1

Modelsim Output

best wishes,
gökhan öztürk

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Differences on std_logic in Vhdl

Mar 18

Yazan: 

Hi everyone,
today i will show you how to merge the st_logic bits 
and differecences between 0 to n and n down to 0.
library ieee;
use ieee.std_logic_1164.all;

entity ozturkgokhan is
port( a : out std_logic_vector(7 downto 0);
b : out std_logic_vector(7 downto 0);
c : out std_logic_vector(0 to 7);
d : out std_logic_vector(7 downto 0));
end ozturkgokhan;

architecture behavioral of ozturkgokhan is
signal gokhan  :std_logic_vector (7 downto 0):="11110000";
signal gokhan1 :std_logic_vector (0 to 7)    :="11110000";

begin
-- merging values
a <= gokhan(1 downto 0) & gokhan(7 downto 4) & gokhan(3 downto 2);
--differecnce between 0 to 7 and 7 downto 0
b <= gokhan;
c <= gokhan;
d <= gokhan1;
end behavioral;
--ozturkgokhan.com
Ekran Alıntısı

Modelsim Output

best wishes,
gökhan öztürk

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Two Bit Up Counter (With Synchronous Reset) at VHDL

Mar 17

Yazan: 

Hi everyone,

Today i made 2 bit upcounter. It counts from "00" to "11". 
Also i have an reset input. The meaning of the synchronous reset is that 
reset comes after the clock sense at the process.
As you might see from the modelsim output figure when 
reset occurs output become "00". 



 library ieee;
use ieee.std_logic_1164.all;
USE ieee.std_logic_unsigned.all;

entity gokhan1 is
port ( clk : in std_logic;
         rest: in std_logic;
         Q : out std_logic_vector(1 downto 0));
end gokhan1;

architecture behavioral of gokhan1 is
signal last: std_logic_vector (1 downto 0);

begin
    process(clk)
    begin
    if rest ='1' then 
        last <= "00";
        -- or you can use Q <= (1=>'0',0=>'0');
        -- or Q<= (others =>'0');
            elsif rising_edge(clk) then
            last <= last+1;
            else 
            last <= last;
    end if;
    end process;
    Q <= last;
--ozturkgokhan.com
end behavioral; 



ekran
Modelsim Output


Best Wishes,


gökhan öztürk

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