90 lines
2.6 KiB
VHDL
90 lines
2.6 KiB
VHDL
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-- filename: blinker.vhd
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-- kind: vhdl file
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-- first created: 18.06.2012
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-- created by: zas
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--------------------------------------------------------------------------------
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-- History:
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-- v0.1 : zas 18.06.2012 -- Initial Version
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--------------------------------------------------------------------------------
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-- Description:
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-- For let blinking a LED with an signal event
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-- Mode = 0 (reactive on rising edge)
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-- ___________________________________________
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-- input ____/
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-- ___________________
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-- output ____/ \_______________________
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-- time 0s 0.5s 1s
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--
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-- _
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-- input ____/ \_________________________________________
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-- ___________________
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-- output ____/ \_______________________
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-- time 0s 0.5s 1s
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----
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-- Mode = 1 (reactive on falling edge)
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-- _____
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-- input \__________________________________________
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-- ___________________
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-- output ______/ \_____________________
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-- time 0s 0.5s 1s
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--
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-- _
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-- input ____/ \_________________________________________
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-- ___________________
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-- output ______ / \____________________
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-- time 0s 0.5s 1s
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--
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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.NUMERIC_STD.all;
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LIBRARY Common;
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USE Common.CommonLib.all;
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ARCHITECTURE arch OF blinker IS
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constant c : integer := clockFrequency/2; -- 500ms blink
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signal cnt : unsigned(requiredBitNb(c)-1 downto 0);
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signal en_delay : std_ulogic;
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signal blink_int : std_ulogic;
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BEGIN
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process(reset, clock)
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begin
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if reset = '1' then
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en_delay <= '0';
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blink_int <= '0';
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cnt <= (others => '0');
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elsif rising_edge(clock) then
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en_delay <= en;
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-- detect rising_edge
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if mode = 0 then
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if blink_int = '0' and en_delay = '0' and en = '1' then
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blink_int <= '1';
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end if;
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else
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-- detect falling edge
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if blink_int = '0' and en_delay = '1' and en = '0' then
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blink_int <= '1';
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end if;
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end if;
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-- blink
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if blink_int = '1' then
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if (cnt < c) then
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cnt <= cnt + 1;
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else
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cnt <= (others => '0');
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blink_int <= '0';
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end if;
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end if;
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end if;
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end process;
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-- Set output
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blink <= blink_int;
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END ARCHITECTURE arch;
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