Add scrolling timer

soc/testbench/scrolling_timer_tb.vhd

@@ -0,0 +1,77 @@
+-- See the file "LICENSE" for the full license governing this code. --
+LIBRARY ieee;
+USE ieee.std_logic_1164.ALL;
+USE ieee.numeric_std.ALL;
+
+LIBRARY work;
+USE work.lt16soc_peripherals.ALL;
+
+ENTITY scrolling_timer_tb IS
+END ENTITY;
+
+ARCHITECTURE sim OF scrolling_timer_tb IS
+
+    constant CLK_PERIOD : time := 10 ns;
+
+    signal rst : std_logic;
+    signal clk : std_logic := '0';
+
+	signal cnt_start : std_logic := '0';
+    signal cnt_done : std_logic := '0';
+    signal cnt_value : std_logic_vector(31 downto 0) := x"00000000";
+
+    component scrolling_timer is
+        port(
+            clk : in std_logic;
+            rst : in std_logic;
+            cnt_start : in std_logic;
+            cnt_done : out std_logic;
+            cnt_value : in std_logic_vector(31 downto 0)
+        );
+    end component;
+
+BEGIN
+
+	timer: scrolling_timer
+        port map(
+			clk => clk,
+            rst => rst,
+            cnt_start => cnt_start,
+            cnt_done => cnt_done,
+            cnt_value => cnt_value
+    );
+
+    clk_gen: process
+	begin
+		clk	<= not clk;
+		wait for CLK_PERIOD/2;
+	end process clk_gen;
+
+	stimuli: process
+	begin
+        rst <= '1';
+        wait for CLK_PERIOD;
+        rst <= '0';
+
+        wait for CLK_PERIOD*3;
+
+        cnt_value <= x"00000100";
+        cnt_start <= '1';
+        
+        wait for CLK_PERIOD;
+        cnt_start <= '0';
+
+		wait for CLK_PERIOD * 300;
+
+        cnt_value <= x"0000000A";
+        cnt_start <= '1';
+        
+        wait for CLK_PERIOD;
+        cnt_start <= '0';
+        
+        wait for CLK_PERIOD * 15;
+
+		assert false report "Simulation terminated!" severity failure;
+	end process stimuli;
+
+END ARCHITECTURE;