library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_bit.all;
use IEEE.STD_LOGIC_ARITH.all;
use ieee.std_logic_unsigned.all;


ENTITY TENBASET_TxD IS
   PORT (
      clk20                   : IN std_logic;   
      Ethernet_TDp            : OUT bit;   
      Ethernet_TDm            : OUT bit);   
END ENTITY TENBASET_TxD;

ARCHITECTURE translated OF TENBASET_TxD IS


    
   -- "Physical Address" - put the address of the PC you want to send to
   CONSTANT  PhysicalAddress_1     :  bit_vector(7 DOWNTO 0) := "00000000";    
   CONSTANT  PhysicalAddress_2     :  bit_vector(7 DOWNTO 0) := "00000111";    
   CONSTANT  PhysicalAddress_3     :  bit_vector(7 DOWNTO 0) := "10010101";    
   CONSTANT  PhysicalAddress_4     :  bit_vector(7 DOWNTO 0) := "00001011";    
   CONSTANT  PhysicalAddress_5     :  bit_vector(7 DOWNTO 0) := "11111011";    
   CONSTANT  PhysicalAddress_6     :  bit_vector(7 DOWNTO 0) := "10101111";    
   --////////////////////////////////////////////////////////////////////
   -- sends a packet roughly every second
   SIGNAL counter                  :  bit_vector(23 DOWNTO 0):="000000000000000000000000";   
   SIGNAL StartSending             :  bit;   
   --////////////////////////////////////////////////////////////////////
   -- we send a UDP packet, 18 bytes payload
   
   
   SIGNAL rdaddress                :  bit_vector(6 DOWNTO 0);   
   SIGNAL pkt_data                 :  bit_vector(7 DOWNTO 0);   
   --////////////////////////////////////////////////////////////////////
   -- and finally the 10BASE-T's magic
   SIGNAL ShiftCount               :  bit_vector(3 DOWNTO 0);   
   SIGNAL SendingPacket            :  bit;   
   SIGNAL temp_xhdl3               :  bit_vector(3 DOWNTO 0);   
   SIGNAL readram                  :  bit;   
   SIGNAL temp_xhdl4               :  bit_vector(6 DOWNTO 0);   
   SIGNAL ShiftData                :  bit_vector(7 DOWNTO 0);   
   SIGNAL temp_xhdl5               :  bit_vector(7 DOWNTO 0);   
   SIGNAL CRC                      :  bit_vector(31 DOWNTO 0);   
   SIGNAL CRCflush                 :  bit;   
   SIGNAL CRCinit                  :  bit;   
   SIGNAL temp_xhdl6               :  bit;   
   SIGNAL CRCinput                 :  bit;   
   SIGNAL temp_xhdl7               :  bit_vector(31 DOWNTO 0);   
   SIGNAL LinkPulseCount           :  bit_vector(17 DOWNTO 0);   
   SIGNAL temp_xhdl8               :  bit_vector(17 DOWNTO 0);   
   SIGNAL LinkPulse                :  bit;   
   -- TP_IDL, shift-register and manchester encoder
   SIGNAL SendingPacketData        :  bit;   
   SIGNAL idlecount                :  bit_vector(2 DOWNTO 0);   
   SIGNAL temp_xhdl9               :  bit;   
   SIGNAL dataout                  :  bit;   
   SIGNAL qo                       :  bit;   
   SIGNAL temp_xhdl10              :  bit;   
   SIGNAL qoe                      :  bit;   
   SIGNAL temp_xhdl11              :  bit;   
   SIGNAL temp_xhdl12              :  bit;   
   SIGNAL Ethernet_TDp_xhdl1       :  bit;   
   SIGNAL Ethernet_TDm_xhdl2       :  bit;   

BEGIN
   Ethernet_TDp <= Ethernet_TDp_xhdl1;
   Ethernet_TDm <= Ethernet_TDm_xhdl2;

   PROCESS (clk20)
   BEGIN
      IF (clk20'EVENT AND clk20 = '1') THEN 
         counter<= counter + "000000000000000000000001";    
      END IF;
   END PROCESS;
 
   PROCESS (clk20)
   BEGIN
      IF (clk20'EVENT AND clk20 = '1') THEN
         StartSending <= and_br(counter);    
      END IF;
   END PROCESS;

   PROCESS (clk20)
   BEGIN
      IF (clk20'EVENT AND clk20 = '1') THEN
         CASE rdaddress IS
            -- Ethernet preamble
            
            WHEN "0000000" =>
                     pkt_data <= "01010101";    
            WHEN "0000001" =>
                     pkt_data <= "01010101";    
            WHEN "0000010" =>
                     pkt_data <= "01010101";    
            WHEN "0000011" =>
                     pkt_data <= "01010101";    
            WHEN "0000100" =>
                     pkt_data <= "01010101";    
            WHEN "0000101" =>
                     pkt_data <= "01010101";    
            WHEN "0000110" =>
                     pkt_data <= "01010101";    
            WHEN "0000111" =>
                     pkt_data <= "11010101";    
            -- Ethernet header
            
            WHEN "0001000" =>
                     pkt_data <= PhysicalAddress_1;    
            WHEN "0001001" =>
                     pkt_data <= PhysicalAddress_2;    
            WHEN "0001010" =>
                     pkt_data <= PhysicalAddress_3;    
            WHEN "0001011" =>
                     pkt_data <= PhysicalAddress_4;    
            WHEN "0001100" =>
                     pkt_data <= PhysicalAddress_5;    
            WHEN "0001101" =>
                     pkt_data <= PhysicalAddress_6;    
            WHEN "0001110" =>
                     pkt_data <= "00000000";    
            WHEN "0001111" =>
                     pkt_data <= "00010010";    
            WHEN "0010000" =>
                     pkt_data <= "00110100";    
            WHEN "0010001" =>
                     pkt_data <= "01010110";    
            WHEN "0010010" =>
                     pkt_data <= "01111000";    
            WHEN "0010011" =>
                     pkt_data <= "10010000";    
            -- IP header
            
            WHEN "0010100" =>
                     pkt_data <= "00001000";    
            WHEN "0010101" =>
                     pkt_data <= "00000000";    
            WHEN "0010110" =>
                     pkt_data <= "01000101";    
            WHEN "0010111" =>
                     pkt_data <= "00000000";    
            WHEN "0011000" =>
                     pkt_data <= "00000000";    
            WHEN "0011001" =>
                     pkt_data <= "00101110";    
            WHEN "0011010" =>
                     pkt_data <= "00000000";    
            WHEN "0011011" =>
                     pkt_data <= "00000000";    
            WHEN "0011100" =>
                     pkt_data <= "00000000";    
            WHEN "0011101" =>
                     pkt_data <= "00000000";    
            WHEN "0011110" =>
                     pkt_data <= "10000000";    
            WHEN "0011111" =>
                     pkt_data <= "00010001";    
            WHEN "0100000" =>
                     pkt_data <= "10000110";    
            WHEN "0100001" =>
                     pkt_data <= "01101111";    
            WHEN "0100010" =>
                     pkt_data <= "11000000";    
            WHEN "0100011" =>
                     pkt_data <= "10101000";    
            WHEN "0100100" =>
                     pkt_data <= "00000000";    
            WHEN "0100101" =>
                     pkt_data <= "00000001";    
            WHEN "0100110" =>
                     pkt_data <= "11000000";    
            WHEN "0100111" =>
                     pkt_data <= "10101000";    
            WHEN "0101000" =>
                     pkt_data <= "00000000";    
            WHEN "0101001" =>
                     pkt_data <= "00000011";    
            -- UDP header
            
            WHEN "0101010" =>
                     pkt_data <= "00000100";    
            WHEN "0101011" =>
                     pkt_data <= "00000000";    
            WHEN "0101100" =>
                     pkt_data <= "00000100";    
            WHEN "0101101" =>
                     pkt_data <= "00000000";    
            WHEN "0101110" =>
                     pkt_data <= "00000000";    
            WHEN "0101111" =>
                     pkt_data <= "00011010";    
            WHEN "0110000" =>
                     pkt_data <= "00000000";    
            WHEN "0110001" =>
                     pkt_data <= "00000000";    
            -- payload
            
            WHEN "0110010" =>
                     pkt_data <= "00000000";    --  put here the data that you want to send
            WHEN "0110011" =>
                     pkt_data <= "00000001";    --  put here the data that you want to send
            WHEN "0110100" =>
                     pkt_data <= "00000010";    --  put here the data that you want to send
            WHEN "0110101" =>
                     pkt_data <= "00000011";    --  put here the data that you want to send
            WHEN "0110110" =>
                     pkt_data <= "00000100";    --  put here the data that you want to send
            WHEN "0110111" =>
                     pkt_data <= "00000101";    --  put here the data that you want to send
            WHEN "0111000" =>
                     pkt_data <= "00000110";    --  put here the data that you want to send
            WHEN "0111001" =>
                     pkt_data <= "00000111";    --  put here the data that you want to send
            WHEN "0111010" =>
                     pkt_data <= "00001000";    --  put here the data that you want to send
            WHEN "0111011" =>
                     pkt_data <= "00001001";    --  put here the data that you want to send
            WHEN "0111100" =>
                     pkt_data <= "00001010";    --  put here the data that you want to send
            WHEN "0111101" =>
                     pkt_data <= "00001011";    --  put here the data that you want to send
            WHEN "0111110" =>
                     pkt_data <= "00001100";    --  put here the data that you want to send
            WHEN "0111111" =>
                     pkt_data <= "00001101";    --  put here the data that you want to send
            WHEN "1000000" =>
                     pkt_data <= "00001110";    --  put here the data that you want to send
            WHEN "1000001" =>
                     pkt_data <= "00001111";    --  put here the data that you want to send
            WHEN "1000010" =>
                     pkt_data <= "00010000";    --  put here the data that you want to send
            WHEN "1000011" =>
                     pkt_data <= "00010001";    --  put here the data that you want to send
            WHEN OTHERS  =>
                     pkt_data <= "00000000";    
            
         END CASE;
      END IF;
   END PROCESS;

   PROCESS (clk20)
   BEGIN
      IF rising_edge(clk20) THEN
         IF (StartSending = '1') THEN
            SendingPacket <= '1';    
         ELSE
            IF (ShiftCount = "1110" AND rdaddress = "1001000") THEN
               SendingPacket <= '0';    
            END IF;
         END IF;
      END IF;
   END PROCESS;
   temp_xhdl3 <= ShiftCount + "0001" WHEN SendingPacket = '1' ELSE "1111";

   PROCESS (clk20)
   BEGIN
      IF (clk20'EVENT AND clk20 = '1') THEN
         ShiftCount <= temp_xhdl3;    
      END IF;
   END PROCESS;
   readram <= TO_BIT(ShiftCount = "1111") ;
   temp_xhdl4 <= rdaddress + "0000001" WHEN SendingPacket = '1' ELSE "0000000";

   PROCESS (clk20)
   BEGIN
      IF (clk20'EVENT AND clk20 = '1') THEN
         IF (ShiftCount = "1111") THEN
            rdaddress <= temp_xhdl4;    
         END IF;
      END IF;
   END PROCESS;
   temp_xhdl5 <= pkt_data WHEN readram = '1' ELSE '0' & ShiftData(7 DOWNTO 1);

   PROCESS (clk20)
   BEGIN
      IF (clk20'EVENT AND clk20 = '1') THEN
         -- generate the CRC32
         
         IF (ShiftCount(0) = '1') THEN
            ShiftData <= temp_xhdl5;    
         END IF;
      END IF;
   END PROCESS;

   PROCESS (clk20)
   BEGIN
      IF (clk20'EVENT AND clk20 = '1') THEN
         IF (CRCflush = '1') THEN
            CRCflush <= SendingPacket;    
         ELSE
            IF (readram = '1') THEN
               CRCflush <= TO_BIT(rdaddress = "1000100");    
            END IF;
         END IF;
      END IF;
   END PROCESS;

   PROCESS (clk20)
   BEGIN
      IF (clk20'EVENT AND clk20 = '1') THEN
         IF (readram = '1') THEN
            CRCinit <= TO_BIT(rdaddress = "0000111");    
         END IF;
      END IF;
   END PROCESS;
   temp_xhdl6 <= '0' WHEN CRCflush = '1' ELSE (ShiftData(0) XOR CRC(31));
   CRCinput <= temp_xhdl6 ;
   temp_xhdl7 <= "00000000000000000000000000000000" WHEN CRCinit = '1' ELSE (CRC(30 DOWNTO 0) & '0' XOR (CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput & CRCinput AND "00000100110000010001110110110111"));

   PROCESS (clk20)
   BEGIN
      IF (clk20'EVENT AND clk20 = '1') THEN
         -- generate the NLP
         
         IF (ShiftCount(0) = '1') THEN
            CRC <= temp_xhdl7;    
         END IF;
      END IF;
   END PROCESS;
   temp_xhdl8 <= "000000000000000000" WHEN SendingPacket = '1' ELSE LinkPulseCount + "000000000000000001";

   PROCESS (clk20)
   BEGIN
      IF (clk20'EVENT AND clk20 = '1') THEN
         LinkPulseCount <= temp_xhdl8;    
      END IF;
   END PROCESS;

   PROCESS (clk20)
   BEGIN
      IF (clk20'EVENT AND clk20 = '1') THEN
         LinkPulse <= and_br(LinkPulseCount(17 DOWNTO 1));    
      END IF;
   END PROCESS;

   PROCESS (clk20)
   BEGIN
      IF ((clk20'EVENT) AND (clk20 = '1')) THEN
         SendingPacketData <= SendingPacket;    
      END IF;
   END PROCESS;

   PROCESS (clk20)
   BEGIN
      IF (clk20'EVENT AND clk20 = '1') THEN
         IF (SendingPacketData = '1') THEN
            idlecount <= "000";    
         ELSE
            IF (NOT and_br(idlecount) = '1') THEN
               idlecount <= idlecount + "001";    
            END IF;
         END IF;
      END IF;
   END PROCESS;
   temp_xhdl9 <= NOT CRC(31) WHEN CRCflush = '1' ELSE ShiftData(0);
   dataout <= temp_xhdl9 ;
   temp_xhdl10 <= (NOT dataout XOR ShiftCount(0)) WHEN SendingPacketData = '1' ELSE '1';

   PROCESS (clk20)
   BEGIN
      IF (clk20'EVENT AND clk20 = '1') THEN
         qo <= temp_xhdl10;    
      END IF;
   END PROCESS;

   PROCESS (clk20)
   BEGIN
      IF (clk20'EVENT AND clk20 = '1') THEN
         qoe <= SendingPacketData OR LinkPulse OR TO_BIT(idlecount < "110");    
      END IF;
   END PROCESS;
   temp_xhdl11 <= qo WHEN qoe = '1' ELSE '0';

   PROCESS (clk20)
   BEGIN
      IF (clk20'EVENT AND clk20 = '1') THEN
         Ethernet_TDp_xhdl1 <= temp_xhdl11;    
      END IF;
   END PROCESS;
   temp_xhdl12 <= NOT qo WHEN qoe = '1' ELSE '0';

   PROCESS (clk20)
   BEGIN
      IF (clk20'EVENT AND clk20 = '1') THEN
         Ethernet_TDm_xhdl2 <= temp_xhdl12;    
      END IF;
   END PROCESS;

END ARCHITECTURE translated;