mirror of
https://github.com/Klagarge/Cursor.git
synced 2024-11-30 04:43:26 +00:00
84 lines
2.8 KiB
VHDL
84 lines
2.8 KiB
VHDL
-- filename: debouncer.vhd
|
|
-- kind: vhdl file
|
|
-- first created: 05.03.2012
|
|
-- created by: zas
|
|
--------------------------------------------------------------------------------
|
|
-- History:
|
|
-- v0.1 : zas 05.03.2012 -- Initial Version
|
|
-- v0.2 : cof 22.01.2013 -- synchronization to clock
|
|
-- -- direct reaction on both edges
|
|
--------------------------------------------------------------------------------
|
|
-- Description:
|
|
-- Debounces a button on both edges.
|
|
-- _ _ ____________________ _ _
|
|
-- input ____/ \_/ \_/ \_/ \_/ \______
|
|
-- _____________________________
|
|
-- output _____/ \____________
|
|
--
|
|
--------------------------------------------------------------------------------
|
|
|
|
ARCHITECTURE rtl OF debouncer IS
|
|
|
|
signal debounceCounter : unsigned(counterBitNb-1 downto 0);
|
|
signal inputSynch, inputDelayed, inputChanged : std_ulogic;
|
|
|
|
BEGIN
|
|
------------------------------------------------------------------------------
|
|
-- Synchronize input to clock
|
|
synchInput: process(reset, clock)
|
|
begin
|
|
if reset = '1' then
|
|
inputSynch <= '0';
|
|
elsif rising_edge(clock) then
|
|
inputSynch <= input xor invertInput;
|
|
end if;
|
|
end process synchInput;
|
|
|
|
------------------------------------------------------------------------------
|
|
-- Find edge on input
|
|
delayInput: process(reset, clock)
|
|
begin
|
|
if reset = '1' then
|
|
inputDelayed <= '0';
|
|
elsif rising_edge(clock) then
|
|
inputDelayed <= inputSynch;
|
|
end if;
|
|
end process delayInput;
|
|
|
|
inputChanged <= '1' when inputDelayed /= inputSynch
|
|
else '0';
|
|
|
|
------------------------------------------------------------------------------
|
|
-- Debounce counter
|
|
countDeadTime: process(reset, clock)
|
|
begin
|
|
if reset = '1' then
|
|
debounceCounter <= (others => '0');
|
|
elsif rising_edge(clock) then
|
|
if debounceCounter = 0 then
|
|
if inputChanged = '1' then
|
|
debounceCounter <= debounceCounter - 1;
|
|
end if;
|
|
else
|
|
debounceCounter <= debounceCounter - 1;
|
|
end if;
|
|
end if;
|
|
end process countDeadTime;
|
|
|
|
------------------------------------------------------------------------------
|
|
-- Update output
|
|
updateOutput: process(reset, clock)
|
|
begin
|
|
if reset = '1' then
|
|
debounced <= '0';
|
|
elsif rising_edge(clock) then
|
|
if (inputChanged = '1') and (debounceCounter = 0) then
|
|
debounced <= input;
|
|
elsif debounceCounter = 1 then
|
|
debounced <= input;
|
|
end if;
|
|
end if;
|
|
end process updateOutput;
|
|
|
|
END ARCHITECTURE rtl;
|