Subversion Repositories ttl_library

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

-- Bipolar TTL models (VHDL)                                         --

-- David R Brooks                                                    --

-- June, 2016.  Perth, Australia                                     --

-- Compliance: VHDL 2008                                             --

-- Testbench for SN74LS38N: Quad 2-input NAND buffer (open collector)--

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

library ieee;

    use ieee.std_logic_1164.all;

    use ieee.std_logic_misc.all;

    use ieee.numeric_std.all;

    use work.LSTTL.all;

    use work.TTLPrivate.all;

entity Testbench_38 is     -- Top-level bench

generic(

    StimClk  : std_logic      := '1';

    CheckClk : std_logic      := '0';

    Period   : time           := 50 ns;

    Finish   : time           := 20 us;

    SevLevel : severity_level := failure

);

end entity;

architecture Test of Testbench_38 is

    signal J, B : unsigned(7 downto 0);         -- Test stimuli

    signal D, E : std_logic_vector(3 downto 0); -- Expected & actual results

    begin

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

    -- Standard testbench components

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

    TB: TTLBench

    generic map(

        StimClk  => StimClk,

        CheckClk => CheckClk,

        Period   => Period,

        Finish   => Finish,

        SevLevel => SevLevel

    )

    port map(

        J   => J,

        B   => B,

        CLK => open,

        RS  => open,

        D   => D,

        E   => E

    );

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

    -- Generate expected results (with zero delays)

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

    D(0) <= TTL_OC( not (J(0) and J(1)) );

    D(1) <= TTL_OC( not (J(2) and J(3)) );

    D(2) <= TTL_OC( not (J(4) and J(5)) );

    D(3) <= TTL_OC( not (J(6) and J(7)) );

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

    -- Device Under Test...                        

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

    DUT: SN74LS38N

    port map(

    X_1  => J(0),  -- 1A

    X_2  => J(1),  -- 1B

    X_3  => E(0),  -- 1Y\

    X_4  => J(2),  -- 2A

    X_5  => J(3),  -- 2B

    X_6  => E(1),  -- 2Y\

    X_7  => open,  -- GND

    X_8  => E(2),  -- 3Y\

    X_9  => J(4),  -- 3B

    X_10 => J(5),  -- 3A

    X_11 => E(3),  -- 4Y\

    X_12 => J(6),  -- 4B

    X_13 => J(7),  -- 4A

    X_14 => open   -- Vcc 

);

end architecture Test;