Add scrolling controller and testbench

soc/peripheral/scrolling_controller.vhd

@@ -0,0 +1,104 @@
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+entity scrolling_controller is
+    port(
+        clk : in std_logic;
+        rst : in std_logic;
+        on_off : in std_logic;
+        cnt_start : out std_logic;
+        cnt_done : in std_logic;
+        next_char : out std_logic;
+        hex_char : in std_logic_vector(4 downto 0);
+        seg_data : out std_logic_vector(3 downto 0);
+        seg_off : out std_logic;
+        seg_shift : out std_logic;
+        seg_write : out std_logic;
+        seg_clear : out std_logic
+    );
+end entity scrolling_controller;
+
+architecture Behavioral of scrolling_controller is
+
+    type state_type is (s_off, s_wait, s_update);
+    signal state : state_type;
+
+begin
+
+	process(clk)
+	begin
+		if clk'event and clk='1' then
+			if rst = '1' then
+                state <= s_off;
+                seg_clear <= '1';
+                cnt_start <= '0';
+                next_char <= '0';
+
+                seg_data <= (others => '0');
+                seg_off <= '0';
+                seg_shift <= '0';
+                seg_write <= '0';
+            else
+                case state is
+                    when s_off =>
+                        if on_off = '0' then
+                            state <= s_off;
+                            seg_shift <= '0';
+                            seg_write <= '0';
+                            seg_clear <= '0';
+                            cnt_start <= '0';
+                            next_char <= '0';
+                        else
+                            state <= s_update;
+                            seg_data <= hex_char(3 downto 0);
+                            seg_shift <= '1';
+                            seg_write <= '1';
+                            seg_clear <= '0';
+                            seg_off <= hex_char(4);
+                            cnt_start <= '1';
+                            next_char <= '1';
+                        end if;
+                    when s_wait =>
+                        if on_off = '1' then
+                            state <= s_off;
+                            seg_clear <= '1';
+                            cnt_start <= '0';
+                            next_char <= '0';
+                        elsif cnt_done = '0' then
+                            state <= s_wait;
+                            seg_shift <= '0';
+                            seg_write <= '0';
+                            seg_clear <= '0';
+                            cnt_start <= '0';
+                            next_char <= '0';
+                        else -- cnt_cone = '1'
+                            state <= s_update;
+                            seg_shift <= '0';
+                            seg_write <= '0';
+                            seg_clear <= '0';
+                            cnt_start <= '1';
+                            next_char <= '1';
+                        end if;
+                    when s_update =>
+                        if on_off = '0' then
+                            state <= s_wait;
+                            seg_data <= hex_char(3 downto 0);
+                            seg_shift <= '1';
+                            seg_write <= '1';
+                            seg_clear <= '0';
+                            seg_off <= hex_char(4);
+                            cnt_start <= '0';
+                            next_char <= '0';
+                        else
+                            state <= s_off;
+                            seg_clear <= '1';
+                            cnt_start <= '0';
+                            next_char <= '0';
+                        end if;
+                end case;
+            end if;
+		end if;
+	end process;
+
+end Behavioral;

soc/testbench/scrolling_controller_tb.vhd

@@ -0,0 +1,102 @@
+-- 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_controller_tb IS
+END ENTITY;
+
+ARCHITECTURE sim OF scrolling_controller_tb IS
+
+    constant CLK_PERIOD : time := 10 ns;
+
+    signal rst : std_logic;
+    signal clk : std_logic := '0';
+
+    signal on_off : std_logic := '0';
+    signal cnt_start : std_logic := '0';
+    signal cnt_done : std_logic := '0';
+    signal next_char : std_logic := '0';
+    signal hex_char : std_logic_vector(4 downto 0) := (others => '0');
+    signal seg_data : std_logic_vector(3 downto 0) := (others => '0');
+    signal seg_off : std_logic := '0';
+    signal seg_shift : std_logic := '0';
+    signal seg_write : std_logic := '0';
+    signal seg_clear : std_logic := '0';
+
+    component scrolling_controller
+        port(
+            clk : in std_logic;
+            rst : in std_logic;
+            on_off : in std_logic;
+            cnt_start : out std_logic;
+            cnt_done : in std_logic;
+            next_char : out std_logic;
+            hex_char : in std_logic_vector(4 downto 0);
+            seg_data : out std_logic_vector(3 downto 0);
+            seg_off : out std_logic;
+            seg_shift : out std_logic;
+            seg_write : out std_logic;
+            seg_clear : out std_logic
+        );
+    end component;
+BEGIN
+
+	controller: scrolling_controller
+        port map(
+			clk => clk,
+            rst => rst,
+            on_off => on_off,
+            cnt_start => cnt_start,
+            cnt_done => cnt_done,
+            next_char => next_char,
+            hex_char => hex_char,
+            seg_data => seg_data,
+            seg_off => seg_off,
+            seg_shift => seg_shift,
+            seg_write => seg_write,
+            seg_clear => seg_clear
+    );
+
+    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;
+
+        hex_char <= "01010";
+
+        wait for CLK_PERIOD * 2;
+        on_off <= '1';
+
+        wait for CLK_PERIOD;
+        on_off <= '0';
+
+        wait for CLK_PERIOD*3;
+        hex_char <= "00101";
+        cnt_done <= '1';
+
+        wait for CLK_PERIOD;
+        cnt_done <= '0';
+
+        wait for CLK_PERIOD * 3;
+        on_off <= '1';
+        hex_char <= "01111";
+
+        wait for CLK_PERIOD * 5;
+
+		assert false report "Simulation terminated!" severity failure;
+	end process stimuli;
+
+END ARCHITECTURE;