git.zerfleddert.de Git - raggedstone/blob - dhwk/source/ser_par_con.vhd

   1 -- $Id: ser_par_con.vhd,v 1.3 2007-03-11 12:24:35 sithglan Exp $
   2
   3 library ieee;
   4 use ieee.std_logic_1164.all;
   5 use ieee.std_logic_unsigned.all;
   6
   7 entity SER_PAR_CON is
   8         port
   9         (
  10                 PCI_CLOCK :in std_logic;
  11                 RESET :in std_logic;
  12                 SPC_ENABLE :in std_logic; -- Driver Enable Sender/Receiver
  13                 SYNC_R_FIFO_FFn :in std_logic; -- FIFO Full Flag (low active)
  14                 SERIAL_IN :in std_logic; -- Serial Input
  15                 R_FIFO_WRITEn :out std_logic; -- FIFO Write (low active)
  16                 SPC_RDY_OUT :out std_logic; -- Ready to Receive Data
  17                 PAR_OUT :out std_logic_vector(7 downto 0)
  18         );
  19 end entity SER_PAR_CON;
  20
  21
  22 architecture SER_PAR_CON_DESIGN of SER_PAR_CON is
  23
  24 -- constant STATE_RECV :std_logic_vector(3 downto 0) := "0001";
  25         constant STATE_RECV_START_BIT :std_logic_vector(3 downto 0) := "0010";
  26         constant STATE_RECV_BIT_0 :std_logic_vector(3 downto 0) := "0011";
  27         constant STATE_RECV_BIT_1 :std_logic_vector(3 downto 0) := "0100";
  28         constant STATE_RECV_BIT_2 :std_logic_vector(3 downto 0) := "0101";
  29         constant STATE_RECV_BIT_3 :std_logic_vector(3 downto 0) := "0110";
  30         constant STATE_RECV_BIT_4 :std_logic_vector(3 downto 0) := "0111";
  31         constant STATE_RECV_BIT_5 :std_logic_vector(3 downto 0) := "1000";
  32         constant STATE_RECV_BIT_6 :std_logic_vector(3 downto 0) := "1001";
  33         constant STATE_RECV_BIT_7 :std_logic_vector(3 downto 0) := "1010";
  34         constant STATE_RECV_FIFOFULL :std_logic_vector(3 downto 0) := "1011";
  35
  36         signal COUNT :std_logic_vector (3 downto 0);
  37         signal STATE :std_logic_vector (3 downto 0);
  38         signal STARTBIT :std_logic_vector (3 downto 0);
  39
  40
  41         attribute syn_state_machine:boolean;
  42         attribute syn_state_machine of STATE: signal is false;
  43         attribute syn_state_machine of COUNT: signal is false;
  44
  45 begin
  46
  47         process(PCI_CLOCK)
  48         begin
  49                 if (PCI_CLOCK'event and PCI_CLOCK = '1') then
  50                         if ("0000" < COUNT) then
  51                                 COUNT <= COUNT - 1;
  52                         end if;
  53
  54  -- war nicht das Problem des Datenverlusts
  55  -- if (R_FIFO_WRITEn = '0' and COUNT = "0000") then
  56  -- R_FIFO_WRITEn <= '1';
  57  --- end if;
  58
  59                         if (RESET = '1') then
  60                                 STATE <= STATE_RECV_START_BIT;
  61                                 COUNT <= "0000";
  62                                 R_FIFO_WRITEn <= '1';
  63
  64                         elsif (SPC_ENABLE = '1') then
  65
  66                                 if (STATE = STATE_RECV_START_BIT) then
  67                                         R_FIFO_WRITEn <= '1';
  68                                         if (STARTBIT = "0011") then
  69                                                 COUNT <= "0011";
  70                                                 STATE <= STATE_RECV_BIT_0;
  71                                         end if;
  72
  73                                 elsif (STATE = STATE_RECV_FIFOFULL) then
  74                                         if (SYNC_R_FIFO_FFn = '1') then
  75                                                 R_FIFO_WRITEn <= '0';
  76                                                 STATE <= STATE_RECV_START_BIT;
  77                                         end if;
  78
  79                                 elsif (COUNT = "0000") then
  80                                         COUNT <= "0011";
  81                                         case STATE is
  82
  83                                         when STATE_RECV_BIT_0 =>
  84                                                 PAR_OUT(0) <= STARTBIT(0);
  85                                                 STATE <= STATE_RECV_BIT_1;
  86
  87                                         when STATE_RECV_BIT_1 =>
  88                                                 PAR_OUT(1) <= STARTBIT(0);
  89                                                 STATE <= STATE_RECV_BIT_2;
  90
  91                                         when STATE_RECV_BIT_2 =>
  92                                                 PAR_OUT(2) <= STARTBIT(0);
  93                                                 STATE <= STATE_RECV_BIT_3;
  94
  95                                         when STATE_RECV_BIT_3 =>
  96                                                 PAR_OUT(3) <= STARTBIT(0);
  97                                                 STATE <= STATE_RECV_BIT_4;
  98
  99                                         when STATE_RECV_BIT_4 =>
 100                                                 PAR_OUT(4) <= STARTBIT(0);
 101                                                 STATE <= STATE_RECV_BIT_5;
 102
 103                                         when STATE_RECV_BIT_5 =>
 104                                                 PAR_OUT(5) <= STARTBIT(0);
 105                                                 STATE <= STATE_RECV_BIT_6;
 106
 107                                         when STATE_RECV_BIT_6 =>
 108                                                 PAR_OUT(6) <= STARTBIT(0);
 109                                                 STATE <= STATE_RECV_BIT_7;
 110
 111                                         when STATE_RECV_BIT_7 =>
 112                                                 PAR_OUT(7) <= STARTBIT(0);
 113
 114                                                 if (SYNC_R_FIFO_FFn = '1') then
 115                                                         STATE <= STATE_RECV_START_BIT;
 116                                                         R_FIFO_WRITEn <= '0';
 117                                                 else
 118                                                         STATE <= STATE_RECV_FIFOFULL;
 119                                                 end if;
 120
 121                                         when others =>
 122                                                 STATE <= STATE_RECV_START_BIT;
 123
 124                                         end case;
 125                                 end if; -- COUNT
 126                         end if; -- RESET ... / SPC_ENABLE ...
 127                 end if; -- PCI_CLOCK ...
 128         end process;
 129
 130         process(PCI_CLOCK)
 131         begin
 132                 if (PCI_CLOCK'event and PCI_CLOCK = '1') then
 133                         SPC_RDY_OUT <= SPC_ENABLE AND SYNC_R_FIFO_FFn;
 134                 end if;
 135         end process;
 136
 137
 138         process(PCI_CLOCK)
 139         begin
 140                 if (PCI_CLOCK'event and PCI_CLOCK = '1') then
 141                         if (RESET = '1') then
 142                                 STARTBIT <= "0000";
 143                         else
 144                                 STARTBIT(0) <= SERIAL_IN;
 145                                 STARTBIT(1) <= STARTBIT(0);
 146                                 STARTBIT(2) <= STARTBIT(1);
 147                                 STARTBIT(3) <= STARTBIT(2);
 148                         end if;
 149                 end if;
 150         end process;
 151
 152 end architecture SER_PAR_CON_DESIGN;