Add scrolling controller and testbench

This commit is contained in:
2022-11-19 19:36:01 +01:00
parent 8b203ac9db
commit bf2b307f38
2 changed files with 206 additions and 0 deletions

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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;

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-- 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;