-- Tarefa09.vhd
-----------------------------------------------------------------------------------
LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;

ENTITY Tarefa09 IS
    PORT(
        ctrl, clock: IN STD_LOGIC; -- ctrl: define se sera crescente ou descrescente | 0 - crescente, 1 - decrescente
        q0, q1: OUT STD_LOGIC
    );
END Tarefa09;

ARCHITECTURE Arc OF Tarefa09 IS
    COMPONENT FFT IS
        PORT(
            clk: IN STD_LOGIC;
            q: OUT STD_LOGIC
        );
    END COMPONENT;

    COMPONENT Mux2x1 IS
        PORT(
            a, b: IN STD_LOGIC;
            sel: IN STD_LOGIC;
            x: OUT STD_LOGIC
        );
    END COMPONENT;

    SIGNAL sq0, sq00, sq1: STD_LOGIC;

    BEGIN

        I0: FFT PORT MAP(clock,sq0);
        I1: Mux2x1 PORT MAP(NOT sq0,sq0,ctrl,sq00);
        I2: FFT PORT MAP(sq00,sq1);

        q0 <= sq0;
        q1 <= sq1;

    END Arc;
-----------------------------------------------------------------------------------

-- FFT.vhd
-----------------------------------------------------------------------------------
LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;

ENTITY FFT IS
    PORT(
        clk: IN STD_LOGIC;
        q: OUT STD_LOGIC
    );
END FFT;

ARCHITECTURE Arc OF FFT IS
    SIGNAL sq: STD_LOGIC;
    BEGIN
        PROCESS(clk)
            BEGIN
                IF(clk'event AND clk='1') THEN -- clk'event: é o evento de subida/descida.
                    q <= (not sq);
                END IF;
            END PROCESS;
    END Arc;
-----------------------------------------------------------------------------------

-- Mux2x1.vhd
-----------------------------------------------------------------------------------
LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;

ENTITY Mux2x1 IS
    PORT(
        a, b: IN STD_LOGIC;
        sel: IN STD_LOGIC;
        x: OUT STD_LOGIC
    );
END Mux2x1;

ARCHITECTURE arc OF Mux2x1 IS
    BEGIN
        PROCESS(a,b,sel)
            BEGIN
                IF(sel = '0') THEN
                    x <= a;
                ELSE
                    x <= b;
                END IF;
        END PROCESS;
    END arc;

-----------------------------------------------------------------------------------