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[hwmod.git] / demo / src / demo.vhd

diff --git a/demo/src/demo.vhd b/demo/src/demo.vhd
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+++ b/demo/src/demo.vhd
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+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+use work.demo_pkg.all;
+
+entity demo is
+  
+  port (
+    clk   : in  std_logic;
+    reset : in  std_logic;
+    leds  : out std_logic_vector(7 downto 0));
+
+end demo;
+
+
+architecture behav of demo is
+
+  function GetShiftDelay return time is
+  begin
+       if SIMULATION then
+               return 1 us;
+       else
+               return 100 ms;
+       end if;
+  end;
+  
+  signal knightlight, knightlight_next : std_logic_vector (7 downto 0);
+  
+  type LEDSTATE_T is (LEFT_S, RIGHT_S);
+  signal ledstate, ledstate_next : LEDSTATE_T;
+
+  subtype counter_t is integer range 0 to (GetShiftDelay / PERIOD);
+  signal counter : counter_t;
+
+  signal syncreset : std_logic;
+  
+begin  -- behav
+
+  process(clk)
+  begin
+    if rising_edge(clk) then
+      syncreset <= reset;
+    end if;
+  end process;
+
+             
+  sync: process(clk, reset)
+  begin
+    if rising_edge(clk) then
+      if syncreset = RESETVALUE then
+        knightlight <= (others => LED_OFF);
+        knightlight(2 downto 0) <= (others => LED_ON);
+        ledstate <= LEFT_S;
+      else
+        knightlight <= knightlight_next;
+        ledstate <= ledstate_next;
+      end if;
+    end if;
+  end process;
+
+  next_state_logic: process(ledstate, knightlight, counter)
+    variable knightlight_tmp : bit_vector (7 downto 0);
+  begin  -- process  
+    -- default assignments
+    ledstate_next <= ledstate;
+    knightlight_tmp := TO_BITVECTOR(knightlight);
+      
+    case ledstate is
+      when LEFT_S =>
+        if counter = counter_t'high - 1 then
+          knightlight_tmp := knightlight_tmp sll 1;          
+        end if;
+        if knightlight_tmp = "11100000" then
+          ledstate_next <= RIGHT_S;
+        end if;
+      when RIGHT_S =>
+        if counter = counter_t'high - 1 then
+          knightlight_tmp := knightlight_tmp srl 1;
+        end if;
+        if knightlight_tmp = "00000111" then
+          ledstate_next <= LEFT_S;
+        end if;
+      when others => null;
+    end case;
+
+    knightlight_next <= TO_STDLOGICVECTOR(knightlight_tmp);
+  end process;
+
+  counterProcess: process(clk, reset)
+  begin  -- process
+    if rising_edge(clk) then
+      if syncreset = RESETVALUE then
+        counter <= 0;
+      elsif counter < counter_t'high then
+        counter <= counter + 1;
+      else
+        counter <= 0;
+      end if;
+    end if;
+  end process;
+      
+  leds <= not knightlight;
+  
+end behav;