Files
nascom2_t80/syncgen.vhd
2009-01-15 19:17:56 +00:00

88 lines
2.2 KiB
VHDL
Executable File

----------------------------------------------------------------------------------
-- Company:
-- Engineer:
--
-- Create Date: 10:37:34 12/08/2008
-- Design Name:
-- Module Name: syncgen - Behavioral
-- Project Name:
-- Target Devices:
-- Tool versions:
-- Description:
--
-- Dependencies:
--
-- Revision:
-- Revision 0.01 - File Created
-- Additional Comments:
--
----------------------------------------------------------------------------------
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
---- Uncomment the following library declaration if instantiating
---- any Xilinx primitives in this code.
--library UNISIM;
--use UNISIM.VComponents.all;
entity syncgen is
Port ( CLKPIXEL : in STD_LOGIC;
VSYNC : out STD_LOGIC;
HSYNC : out STD_LOGIC;
COLUMN : out STD_LOGIC_VECTOR (9 downto 0);
ROW : out STD_LOGIC_VECTOR (9 downto 0));
end syncgen;
architecture Behavioral of syncgen is
signal hsync_i, hsync_i_old: std_logic := '1';
signal vsync_i: std_logic := '1';
signal row_i: std_logic_vector(9 downto 0) := "0000000000";
signal column_i: std_logic_vector(9 downto 0) := "0000000000";
begin
hsync_p: process(CLKPIXEL)
begin
if rising_edge(CLKPIXEL) then
if column_i = 799 then
column_i <= "0000000000";
else
column_i <= column_i + 1;
end if;
if column_i >= 658 and column_i <= 753 then -- generate hsync pulse (one clock early, it is delayed later)
hsync_i <= '0'; -- hsync is low active
else
hsync_i <= '1';
end if;
HSYNC <= hsync_i; -- delay hsync 1 clock
end if;
end process;
vsync_p: process(CLKPIXEL)
begin
if rising_edge(CLKPIXEL) then
if (hsync_i = '0') and (hsync_i_old = '1') then
if row_i = 524 then
row_i <= "0000000000";
else
row_i <= row_i + 1;
end if;
if row_i = 493 then -- generate vsync pulse
vsync_i <= '0'; -- vsync is low active
else
vsync_i <= '1';
end if;
end if;
hsync_i_old <= hsync_i;
end if;
end process;
COLUMN <= column_i;
ROW <= row_i;
VSYNC <= vsync_i;
end Behavioral;