Initial commit

Libs/Common/hdl/debouncerULogicVector_RTL.vhd

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+-- 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
+--------------------------------------------------------------------------------
+-- Description: 
+-- Debounces a button on both edges.
+--             _   _   ____________________   _   _
+-- input  ____/ \_/ \_/                    \_/ \_/ \______
+--              _____________________________
+-- output _____/                             \____________
+--
+--------------------------------------------------------------------------------
+
+ARCHITECTURE rtl OF debouncerULogicVector IS
+ 
+  signal inputNormal : std_ulogic_vector(input'range);
+  signal inputSynch, inputDelayed, inputChanged : std_ulogic;
+  signal debounceCounter : unsigned(counterBitNb-1 downto 0);
+ 
+BEGIN
+  ------------------------------------------------------------------------------
+                                                               -- adapt polarity
+  adaptPolarity: process(input)
+  begin
+    for index in input'range loop
+      inputNormal(index) <= input(index) xor invertInput;
+    end loop;
+  end process adaptPolarity;
+
+  ------------------------------------------------------------------------------
+                                                   -- Synchronize input to clock
+  synchInput: process(reset, clock)
+    variable inputOr : std_ulogic;
+  begin
+    if reset = '1' then
+      inputSynch <= '0';
+    elsif rising_edge(clock) then
+      inputOr := '0';
+      for index in input'range loop
+        inputOr := inputOr or inputNormal(index);
+      end loop;
+      inputSynch <= inputOr;
+    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 <= (others => '0');
+    elsif rising_edge(clock) then
+      if (inputChanged = '1') and (debounceCounter = 0) then
+        debounced <= inputNormal;
+      elsif debounceCounter = 1 then
+        debounced <= inputNormal;
+      end if;
+    end if;
+  end process updateOutput;
+ 
+END ARCHITECTURE rtl;