VHDL Descrição e Síntese de Circuitos Digitais

Soluções do capítulo 4

Exercício 4.9.2

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ENTITY certo1 IS capa_1ra

PORT (a, b : IN BIT;
        c    : IN BOOLEAN;
        x, y, z, k    : OUT BIT);
END certo1;

ARCHITECTURE teste OF certo1 IS
BEGIN
abc: PROCESS (a, b, c)
BEGIN
-- IF a THEN x <= '1';               -- resultado da expressao nao e' boolean
-- END IF;
    IF a = '1' THEN x <= '1';         -- correto resultado da expressao boolean
    END IF;
    IF c THEN z <= '1';               -- correto c tipo boolean
    END IF;
-- IF a AND b = '1' THEN y <= '0';   -- expresao dubia
-- END IF;
    IF (a AND b) = '1' THEN y <= '0';
    END IF;
    IF c AND b = '1' THEN k <= '1'; -- equivale c=TRUE AND b='1'
    END IF;
END PROCESS abc;
END teste;

Exercício 4.9.13

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ENTITY bcd_mps IS capa_1ra

PORT (bcd    : IN BIT_VECTOR(3 DOWNTO 0); -- entrada BCD
        sel    : IN BIT_VECTOR(1 DOWNTO 0); -- selecao mostrador
        sgm    : OUT BIT_VECTOR(6 DOWNTO 0); -- 7 segmentos
        mst    : OUT BIT_VECTOR(3 DOWNTO 0)); -- segmento comum mostrador
END bcd_mps;

ARCHITECTURE comb OF bcd_mps IS
BEGIN
    sel_mostrador: PROCESS(sel)    -- selecao de um dos 4 mostradores
    BEGIN                          -- 0 aciona mostrador
      CASE sel IS
        WHEN "00"   => mst <= "0111";
        WHEN "01"   => mst <= "1011";
        WHEN "10"   => mst <= "1101";
        WHEN OTHERS => mst <= "1110";
      END CASE;
END PROCESS;

bcd_p_7: PROCESS (bcd)          -- converte codigo BCD para 7 segmentos
BEGIN                           -- 1 liga segmento
    CASE bcd IS
    --                            abcdefg
      WHEN "0000" => sgm <= "1111110"; --     -----
      WHEN "0001" => sgm <= "1100000"; --    | f   |
      WHEN "0010" => sgm <= "1011010"; -- e |      | a
      WHEN "0011" => sgm <= "1110011"; --     ------
      WHEN "0100" => sgm <= "1100101"; --    | g   |
      WHEN "0101" => sgm <= "0110111"; -- d |      | b
      WHEN "0110" => sgm <= "0111111"; --    ------
      WHEN "0111" => sgm <= "1100010"; --       c
      WHEN "1000" => sgm <= "1111111";
      WHEN "1001" => sgm <= "1110111";
      WHEN OTHERS => sgm <= "0000000";
    END CASE;
END PROCESS;
END comb;