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david237 |
-----------------------------------------------------------------------
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-- Bipolar TTL models (VHDL) --
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-- David R Brooks --
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-- December, 2016. Perth, Australia --
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-- Compliance: VHDL 2008 --
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-- Testbench for SN74LS299N: 8 bit universal shift/storage register --
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-----------------------------------------------------------------------
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library ieee;
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use ieee.std_logic_1164.all;
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use ieee.std_logic_misc.all;
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use ieee.numeric_std.all;
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use work.LSTTL.all;
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use work.TTLPrivate.all;
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entity Testbench_299 is -- Top-level bench
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generic(
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StimClk : std_logic := '1';
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CheckClk : std_logic := '1';
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Period : time := 40 ns;
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Finish : time := 50 us;
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SevLevel : severity_level := failure
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);
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end entity;
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architecture Test of Testbench_299 is
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signal J, B : unsigned(13 downto 0); -- Test stimuli
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signal D, E : std_logic_vector(9 downto 0); -- Expected & actual results
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signal RS, CLK : std_logic;
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signal OE : std_logic;
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signal DI, R, DT : std_logic_vector(0 to 7);
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alias S0 is J(8);
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alias S1 is J(9);
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alias OE1 is J(10);
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alias OE2 is J(11);
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alias DS0 is J(12);
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alias DS7 is J(13);
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begin
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OE <= not((S1 and S0) or OE1 or OE2);
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DI <= TTL_REV(J(7 downto 0)) when OE = '0' else (others => 'Z');
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E <= "ZZ" & TTL_REV(DI);
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DT <= TTL_REV(J(7 downto 0)) when OE = '0' else R;
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D <= R(7) & R(0) & TTL_REV(DT);
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-----------------------------------------------------------------------
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-- Standard testbench components
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-----------------------------------------------------------------------
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TB: TTLBench
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generic map(
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StimClk => StimClk,
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CheckClk => CheckClk,
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Period => Period,
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Finish => Finish,
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SevLevel => SevLevel
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)
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port map(
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J => J,
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B => B,
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CLK => CLK,
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RS => RS,
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D => D,
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E => E
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);
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-----------------------------------------------------------------------
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-- Generate expected results (with zero delays)
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-----------------------------------------------------------------------
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process(RS, CLK) is
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variable S : unsigned(1 downto 0);
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begin
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if RS = '0' then
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R <= (others => '0');
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elsif rising_edge(CLK) then
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S := (S1, S0);
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case S is
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when "01" => R <= DS0 & R(0 to 6); -- Shift right
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when "10" => R <= R(1 to 7) & DS7; -- Shift left
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when "11" => R <= DT; -- Parallel load
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when others => null; -- "00" hold
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end case;
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end if;
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end process;
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-----------------------------------------------------------------------
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-- Device Under Test...
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-----------------------------------------------------------------------
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DUT: SN74LS299N
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port map(
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X_1 => S0, -- S0
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X_2 => OE1, -- OE1\
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X_3 => OE2, -- OE2\
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X_4 => DI(6), -- IO6
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X_5 => DI(4), -- IO4
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X_6 => DI(2), -- IO2
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X_7 => DI(0), -- IO0
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X_8 => E(8), -- Q0
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X_9 => RS, -- MR\
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X_10 => open, -- GND
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X_11 => DS0, -- DS0
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X_12 => CLK, -- CP
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X_13 => DI(1), -- IO1
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X_14 => DI(3), -- IO3
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X_15 => DI(5), -- IO5
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X_16 => DI(7), -- IO7
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X_17 => E(9), -- Q7
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X_18 => DS7, -- DS7
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X_19 => S1, -- S1
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X_20 => open -- Vcc
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);
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end architecture Test;
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