Subversion Repositories z80soc

-- 3.57 Mhz clock from a 50 Mhz input

-- Ronivon C. costa

-- 03/2008 

------------------------------------------------------------------

library IEEE;

use  IEEE.STD_LOGIC_1164.all;

use  IEEE.STD_LOGIC_ARITH.all;

use  IEEE.STD_LOGIC_UNSIGNED.all;

ENTITY Clock_357Mhz IS

        PORT (

                clock_50Mhz                             : IN    STD_LOGIC;

                clock_357Mhz                    : OUT   STD_LOGIC);

        END Clock_357Mhz;

ARCHITECTURE rtl OF Clock_357Mhz IS

        SIGNAL counter: STD_LOGIC_VECTOR(3 DOWNTO 0);

        SIGNAL clock_357Mhz_int : STD_LOGIC;

BEGIN

        PROCESS (clock_50Mhz)

        BEGIN

                IF clock_50Mhz'EVENT and clock_50Mhz = '1' THEN

                        IF counter < "1110" THEN

                                counter <= counter + 1;

                        ELSE

                                counter <= "0000";

                                clock_357Mhz_int <= not clock_357Mhz_int;

                        END IF;

                END IF;

        clock_357Mhz <= clock_357Mhz_int;

        END PROCESS;

END rtl;