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[/] [ttl_library/] [trunk/] [Testbench/] [Testbench_165.vhd] - Rev 3
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----------------------------------------------------------------------- -- Bipolar TTL models (VHDL) -- -- David R Brooks -- -- June, 2016. Perth, Australia -- -- Compliance: VHDL 2008 -- -- Testbench for SN74LS165N: 8-bit parallel-to-serial converter -- ----------------------------------------------------------------------- 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_165 is -- Top-level bench generic( StimClk : std_logic := '1'; CheckClk : std_logic := '1'; Period : time := 100 ns; Finish : time := 20 us; SevLevel : severity_level := failure ); end entity; architecture Test of Testbench_165 is signal CLK, ICLK : std_logic; signal JC, BC : unsigned(9 downto 0); -- Test stimuli signal D, E : std_logic_vector(1 downto 0); -- Expected & actual results signal PL, RS : std_logic; signal CP1, CP2 : std_logic; signal P1 : std_logic_vector(7 downto 0) := (others => '0'); signal SR : std_logic_vector(7 downto 0); alias DS : std_logic is BC(1); begin P1 <= std_logic_vector(BC(9 downto 2)); ICLK <= not((CP1 and PL) or (CP2 and PL)); D(0) <= SR(7); D(1) <= not SR(7); process(CLK, RS) is variable X : unsigned(5 downto 0); begin if RS = '0' then CP1 <= '0'; CP2 <= '0'; PL <= '0'; elsif rising_edge(CLK) then CP1 <= BC(0); CP2 <= not BC(0); X := BC(X'range); case X is when "000000" => PL <= '0'; when others => PL <= '1'; end case; elsif falling_edge(CLK) then CP1 <= '0'; CP2 <= '0'; end if; end process; ----------------------------------------------------------------------- -- 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) ----------------------------------------------------------------------- process(ICLK, PL) is begin if PL = '0' then -- Asynchronous load SR <= P1; elsif falling_edge(ICLK) then SR <= SR(6 downto 0) & DS; end if; end process; ----------------------------------------------------------------------- -- Device Under Test... ----------------------------------------------------------------------- DUT: SN74LS165N port map( X_1 => PL, -- PL\ X_2 => CP1, -- CP1 X_3 => P1(4), -- P4 X_4 => P1(5), -- P5 X_5 => P1(6), -- P6 X_6 => P1(7), -- P7 X_7 => E(1), -- Q7\ X_8 => open, -- GND X_9 => E(0), -- Q7 X_10 => DS, -- DS X_11 => P1(0), -- P0 X_12 => P1(1), -- P1 X_13 => P1(2), -- P2 X_14 => P1(3), -- P3 X_15 => CP2, -- CP2 X_16 => open -- Vcc ); end architecture Test;