This is the code that was supplied with the Cubic Cyclonium (LED matrix driver) in a hardware tutorial class. Very simple, just copies the bit across the whole row. For example, if LEDS(0) is high, it turns on the entire top row of the LED matrix.
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity LED_DRIVER is
port (
clock : IN std_logic;
resetN : IN std_logic;
LEDS : IN std_logic_vector(7 downto 0);
LED_MATRIX : OUT std_logic_vector(28 downto 0)
);
END LED_DRIVER;
architecture rtl of LED_DRIVER is
SIGNAL COUNTER : unsigned(15 downto 0);
SIGNAL SCANNER : unsigned(20 downto 0);
BEGIN
LED_MATRIX(28 downto 8) <= std_logic_vector(SCANNER);
LED_MATRIX(7 downto 0) <= NOT LEDS;
process(clock,resetN)
begin
if resetN = '0' then
COUNTER <= (others => '0');
SCANNER <= to_unsigned(1,21);
elsif clock = '1' and clock'event then
COUNTER <= COUNTER + 1;
if COUNTER = to_unsigned(0,16) then
SCANNER(20 downto 1) <= SCANNER(19 downto 0);
SCANNER(0) <= SCANNER(20);
else
SCANNER <= SCANNER;
end if;
end if;
end process;
END rtl;
