====== Znakový komparátor ======
===== comparator.vhd =====
<code vhdl>
library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.std_logic_unsigned.all;

entity Comparator is
port(
    CLK: IN std_logic;
    RST: IN std_logic;
    DATA: IN std_logic_vector(6 downto 0);
    
    CNT: OUT std_logic_vector(2 downto 0)
);
end entity Comparator;

architecture Comparator_arch of Comparator is

-- Sem doplnte deklarace vnitrnich signalu pro komunikaci
-- mezi jednotlivymi bloky obvodu. Jako priklad je uveden
-- signal vystupu registru, na zaklade jehoz zmeny je
-- spousten proces cmp_proc (viz sensitivity list tohoto
-- procesu).

signal pre: std_logic_vector(6 downto 0);
signal cmpout: std_logic; --cystup comparatoru
---------------------------------------------------------

begin

-- Zde doplnte kod procesu popisujiciho komparator.
cmp_proc: process(DATA, pre)
begin
 if (pre > DATA) then --predchozi pismenko je vyssi nez soucasne
  cmpout <= '1'; --ano
 else
  cmpout <= '0'; --ne
 end if;
end process cmp_proc;

-- Zde doplnte kod procesu popisujiciho registr.
reg_proc: process(CLK, RST)
begin
 if (RST = '1') then --asynchronni reset
  pre <= "0000000"; --ascii ma 7 bitu
 elsif (CLK'event and CLK = '1') then --nabezna hrana
  pre <= DATA; --uloz vstup
 end if;
end process reg_proc;

-- Zde doplnte kod procesu popisujiciho citac.
cnt_proc: process(CLK, RST)
variable RES: std_logic_vector(2 downto 0); --vysledek (RESult)
begin
 if (RST = '1') then --asynchronni reset
  RES := (others => '0');
 elsif (CLK'event and CLK = '1' and cmpout = '1') then --nabezna hrana a komparator
  RES := RES + 1; --plus 1
 end if;
CNT <= RES; --ulozeni vysedku
end process cnt_proc;

end architecture Comparator_arch;
</code>

===== comparator_tb.vhd =====
<code vhdl>library IEEE;
use IEEE.std_logic_1164.all;

entity TB_Comparator is
end entity TB_Comparator;

architecture TB_Comparator_arch of TB_Comparator is

constant period: time := 10 ns;

component Comparator is
port(
    CLK: IN std_logic;
    RST: IN std_logic;
    DATA: IN std_logic_vector(6 downto 0);
    
    CNT: OUT std_logic_vector(2 downto 0)
);
end component Comparator;

-- Vnitrni signaly test benche
signal clk: std_logic := '0';
signal rst: std_logic := '1';
signal data: std_logic_vector(6 downto 0);
signal cnt: std_logic_vector(2 downto 0);

begin

-- Sem doplnte instanci komponenty Comparator a namapujte
-- jeho vstupy a vystupy na vnitrni signaly test benche.
uut: Comparator
port map (
 CLK => clk,
 RST => rst,
 DATA => data,
 CNT => cnt
);
---------------------------------------------------------

clk <= NOT clk after period / 2;

TB_proc: process
begin
-- Sem doplnte prirazeni testovacich dat na vstupy obvodu.
-- Pro inspiraci je uvedena deaktivace resetu po uplynuti
-- doby k nabezne hrane hodin a vzorove prirazeni ASCII
-- hodnoty znaku X na datovy vstup obvodu. Povsimnete si, 
-- ze v deklaracni casti test benche byl reset implicitne 
-- nastaven na hodnotu '1'.

wait until clk'event AND clk = '1';
rst <= '0'; --odresetujeme

--    X       K       A       L       A       B       0       0
-- 1011000 1001011 1000001 1001100 1000001 1000010 0110000 0110000
data <= "1011000"; --X
wait until clk'event AND clk = '1';

data <= "1001011"; --K
wait until clk'event AND clk = '1';

data <= "1000001"; --A
wait until clk'event AND clk = '1';

data <= "1001100"; --L
wait until clk'event AND clk = '1';

data <= "1000001"; --A
wait until clk'event AND clk = '1';

data <= "1000010"; --B
wait until clk'event AND clk = '1';

data <= "0110000"; --0
wait until clk'event AND clk = '1';

data <= "0110000"; --0
wait until clk'event AND clk = '1';

wait; --stuj
---------------------------------------------------------
end process TB_proc;

end architecture TB_Comparator_arch;
</code>

===== Časový diagram simulace =====
{{ wave.png?1000 |XKALAB00}}

===== Protokol =====
{{proj01.pdf}}