Subversion Repositories parallel_io_through_fiber

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-- Company: 

-- Engineer: 

-- 

-- Create Date:    04:53:24 12/11/2013 

-- Design Name: 

-- Module Name:    optic_transmitter - Behavioral 

-- Project Name: 

-- Target Devices: 

-- Tool versions: 

-- Description: 

--

-- Dependencies: 

--

-- Revision: 

-- Revision 0.01 - File Created

-- Additional Comments: 

--

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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 using

-- arithmetic functions with Signed or Unsigned values

--use IEEE.NUMERIC_STD.ALL;

-- Uncomment the following library declaration if instantiating

-- any Xilinx primitives in this code.

--library UNISIM;

--use UNISIM.VComponents.all;

--each frame of 12bit take 12x4 period + 4 + 2 period  * 4; speed@50Mhz 230Khz

entity optic_transmitter is

    Port (

         iCLK : in  STD_LOGIC;

         s : in  STD_LOGIC_VECTOR (11 downto 0);

    optic_out : out  STD_LOGIC);

end optic_transmitter;

architecture Behavioral of optic_transmitter is

--output flip-flop

signal optic_flop:STD_LOGIC;

signal s_reg:STD_LOGIC_VECTOR(13 downto 0);

signal optic_cnt:STD_LOGIC_VECTOR(5 downto 0);

signal optic_sub_cnt:STD_LOGIC_VECTOR(1 downto 0);

begin

optic_out<=optic_flop;  --output (fiber optic)

optic_stage:process (iCLK)

begin

        if (iCLK'event and iCLK = '1') then

                optic_sub_cnt<=optic_sub_cnt+1;

                if(optic_sub_cnt=0) then

                        if(optic_cnt=0)then

                                s_reg<=(13=>'0')&s(11 downto 0)&(0=>'1');  --0xxxxxxxx1 where the last 1 is halved

                        elsif(optic_cnt(1 downto 0)="00")then

                                s_reg<=s_reg(12 downto 0)&'0';

                        end if;

                        if(optic_cnt(0)=optic_cnt(1)) then       --00 and 11

                                optic_flop<=not optic_cnt(0);

                        else                                                                                    --01 and 10

                                optic_flop<=optic_cnt(0) xor s_reg(13);

                        end if;

                        if(optic_cnt=('1','1','0','1','0','1'))then       --53 because 13x4+2 value

                                optic_cnt<=(others=>'0');

                        else

                                optic_cnt<=optic_cnt+1;

                        end if;

                end if;--optic_sub_cnt divide iCLK

        end if;--iCLK event

end process;

end Behavioral;