Subversion Repositories ttl_library

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

-- Bipolar TTL models (VHDL)                                         --

-- David R Brooks                                                    --

-- December, 2016.  Perth, Australia                                 --

-- Compliance: VHDL 2008                                             --

-- Testbench for SN74LS540N: Octal buffer/line driver (3-state ops)  --

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

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_540 is     -- Top-level bench

generic(

    StimClk  : std_logic      := '1';

    CheckClk : std_logic      := '1';

    Period   : time           := 50 ns;

    Finish   : time           := 20 us;

    SevLevel : severity_level := failure

);

end entity;

architecture Test of Testbench_540 is

    signal RS, OE   : std_logic;

    signal CLK      : std_logic;

    signal JC, BC   : unsigned(9 downto 0);       -- Test stimuli

    signal D,  E    : std_logic_vector(7 downto 0);   -- Expected & actual results

    signal I        : std_logic_vector(7 downto 0);

    alias OEA is JC(9);

    alias OEB is JC(8);

begin

    I  <= std_logic_vector(BC(7 downto 0));

    OE <= not(OEA or OEB);

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

    -- Standard testbench components

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

    TB: TTLBench

    generic map(

        StimClk  => StimClk,

        CheckClk => CheckClk,

        Period   => Period,

        Finish   => Finish,

        SevLevel => SevLevel

    )

    port map(

        J    => JC,

        B    => BC,

        CLK  => CLK,

        RS   => RS,

        D    => D,

        E    => E

    );

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

    -- Generate expected results (with zero delays)

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

    D <= not I when OE = '1' else (others => 'Z');

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

    -- Device Under Test...                        

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

    DUT: SN74LS540N

    port map(

        X_1  => OEA,   -- E1\

        X_2  => I(0),  -- A0

        X_3  => I(1),  -- A1

        X_4  => I(2),  -- A2

        X_5  => I(3),  -- A3

        X_6  => I(4),  -- A4

        X_7  => I(5),  -- A5

        X_8  => I(6),  -- A6

        X_9  => I(7),  -- A7

        X_10 => open,  -- GND

        X_11 => E(7),  -- Y7\

        X_12 => E(6),  -- Y6\

        X_13 => E(5),  -- Y5\

        X_14 => E(4),  -- Y4\

        X_15 => E(3),  -- Y3\

        X_16 => E(2),  -- Y2\

        X_17 => E(1),  -- Y1\

        X_18 => E(0),  -- Y0\

        X_19 => OEB,   -- E2\

        X_20 => open   -- Vcc            

    );

end architecture Test;