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[/] [ttl_library/] [trunk/] [Testbench/] [Testbench_74.vhd] - Rev 4
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----------------------------------------------------------------------- -- Bipolar TTL models (VHDL) -- -- David R Brooks -- -- June, 2016. Perth, Australia -- -- Compliance: VHDL 2008 -- -- Testbench for SN74LS74N: Dual D-type +ve edge-triggered flipflop -- ----------------------------------------------------------------------- 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_74 is -- Top-level bench generic( StimClk : std_logic := '1'; CheckClk : std_logic := '0'; Period : time := 120 ns; Finish : time := 20 us; SevLevel : severity_level := failure ); end entity; architecture Test of Testbench_74 is signal RS : std_logic; signal CLK : std_logic; signal JC, BC : unsigned(1 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 => JC, B => BC, CLK => CLK, RS => RS, D => D, E => E ); ----------------------------------------------------------------------- -- Generate expected results (with zero delays) ----------------------------------------------------------------------- G: for i in 1 downto 0 generate begin SIM: process(CLK, RS) is begin if RS = '0' then D(i) <= '0'; elsif rising_edge(CLK) then D(i) <= BC(i); end if; end process; D(i+2) <= not D(i); end generate; ----------------------------------------------------------------------- -- Device Under Test... ----------------------------------------------------------------------- DUT: SN74LS74N port map( X_1 => RS, -- CD1\ X_2 => BC(0), -- D1 X_3 => CLK, -- CP1 X_4 => '1', -- SD1\ X_5 => E(0), -- Q1 X_6 => E(2), -- Q1\ X_7 => open, -- GND X_8 => E(3), -- Q2\ X_9 => E(1), -- Q2 X_10 => '1', -- SD2\ X_11 => CLK, -- CP2 X_12 => BC(1), -- D2 X_13 => RS, -- CD2\ X_14 => open -- Vcc ); end architecture Test;
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