1 files changed, 32 insertions, 0 deletions
diff --git a/fpga/hp_lcd_driver/debounce.vhdl b/fpga/hp_lcd_driver/debounce.vhdl
new file mode 100644
index 0000000..286367d
--- /dev/null
+++ b/fpga/hp_lcd_driver/debounce.vhdl
@@ -0,0 +1,32 @@
+library IEEE;
+use IEEE.STD_LOGIC_1164.all;
+
+entity debounce is
+    generic (stages : natural := 1);
+    port (clk : in  std_logic;
+          i   : in  std_logic;
+          o   : out std_logic);
+end debounce;
+
+architecture Behavioral of debounce is
+    signal flipflops : std_logic_vector(stages-1 downto 0) := (others => '0');
+    constant zero    : std_logic_vector(stages-1 downto 0) := (others => '0');
+    constant one     : std_logic_vector(stages-1 downto 0) := (others => '1');
+    signal output    : std_logic                           := '0';
+begin
+
+    o <= output;
+
+    process (clk, flipflops, i)
+    begin
+        if rising_edge(clk) then
+            flipflops <= flipflops(flipflops'high-1 downto 0) & i;
+            if flipflops = one and i = '1' then
+                output <= '1';
+            elsif flipflops = zero and i = '0' then
+                output <= '0';
+            end if;
+        end if;
+    end process;
+
+end architecture;