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--! @file

--! @brief Testbench for TriStateBuffer

--! Use standard library and import the packages (std_logic_1164,std_logic_unsigned,std_logic_arith)

LIBRARY ieee;

use ieee.std_logic_1164.all;

use ieee.std_logic_unsigned.all;

use ieee.std_logic_arith.all;

--! Use CPU Definitions package

use work.pkgOpenCPU32.all;

ENTITY testTriStateBuffer IS

END testTriStateBuffer;

--! @brief TriStateBuffer Testbench file

--! @details Test TriStateBuffer by enabling/disabling the sel signal

ARCHITECTURE behavior OF testTriStateBuffer IS

    -- Component Declaration for the Unit Under Test (UUT)

    COMPONENT TriStateBuffer

    generic (n : integer := nBits - 1);                         --! Generic value (Used to easily change the size of the Alu on the package)

         PORT(

                        A : IN  std_logic_vector(n downto 0);            --! Buffer Input

         sel : IN  typeEnDis;                                                           --! Enable or Disable the output

         S : OUT  std_logic_vector(n downto 0)           --! Enable or Disable the output

        );

    END COMPONENT;

   --Inputs

   signal A : std_logic_vector((nBits - 1) downto 0) := (others => '0');  --! Wire to connect Test signal to component

   signal sel : typeEnDis := disable;                                                                                                   --! Wire to connect Test signal to component

        --Outputs

   signal S : std_logic_vector((nBits - 1) downto 0);                                                            --! Wire to connect Test signal to component

BEGIN

        --!Instantiate the Unit Under Test (Multiplexer2_1) (Doxygen bug if it's not commented!)

   uut: TriStateBuffer PORT MAP (

          A => A,

          sel => sel,

          S => S

        );

   --! Process that will change sel signal and verify the Mux outputs

   stim_proc: process

        variable allZ : std_logic_vector((nBits - 1) downto 0) := (others => 'Z');

   begin

      -- Sel disable ---------------------------------------------------------------------------

                wait for 1 ps;

                REPORT "Test tristate on disable mode" SEVERITY NOTE;

                sel <= disable;

                A <= conv_std_logic_vector(10, nBits);

                wait for 1 ns;  -- Wait to stabilize the response

                assert S = allZ report "Output should be high impedance..." severity FAILURE;

                -- Sel disable ---------------------------------------------------------------------------

                wait for 1 ps;

                REPORT "Test tristate on enable mode" SEVERITY NOTE;

                sel <= enable;

                A <= conv_std_logic_vector(10, nBits);

                wait for 1 ns;  -- Wait to stabilize the response

                assert S = (conv_std_logic_vector(10, nBits)) report "Output should be high impedance..." severity FAILURE;

      -- Finish simulation

                assert false report "NONE. End of simulation." severity failure;

   end process;

END;