src/display.vhd

   1 library ieee;
   2 use ieee.std_logic_1164.all;
   3 use ieee.numeric_std.all;
   4 use work.gen_pkg.all;
   5 use work.textmode_vga_component_pkg.all;
   6 use work.textmode_vga_pkg.all;
   7 use work.textmode_vga_platform_dependent_pkg.all;
   8
   9 entity display is
  10         port (
  11                 sys_clk : in std_logic;
  12                 sys_res_n : in std_logic;
  13                 -- History
  14                 d_new_eingabe : in std_logic;
  15                 d_new_result : in std_logic;
  16                 d_zeile : out hzeile;
  17                 d_spalte : out hspalte;
  18                 d_get : out std_logic;
  19                 d_done : in std_logic;
  20                 d_char : in hbyte;
  21                 -- VGA
  22                 command : out std_logic_vector(7 downto 0);
  23                 command_data : out std_logic_vector(31 downto 0);
  24                 free : in std_logic
  25         );
  26 end entity display;
  27
  28 architecture beh of display is
  29         type DISPLAY_STATE is (SIDLE, S_NEW_RESULT, S_NEW_INPUT, S_COUNTUP, S_GETCH,
  30         S_PUTCH, S_WAIT, S_NOP1, S_NOP2);
  31         signal state_int, state_next : DISPLAY_STATE;
  32         signal d_zeile_int, d_zeile_next : hzeile;
  33         signal d_spalte_int, d_spalte_next : hspalte;
  34         signal d_get_int, d_get_next : std_logic;
  35         signal command_int, command_next : std_logic_vector(7 downto 0);
  36         signal command_data_int, command_data_next : std_logic_vector(31 downto 0);
  37 begin
  38         d_zeile <= d_zeile_int;
  39         d_spalte <= d_spalte_int;
  40         d_get <= d_get_int;
  41         command <= command_int;
  42         command_data <= command_data_int;
  43
  44         process(sys_clk, sys_res_n)
  45         begin
  46                 if sys_res_n = '0' then
  47                         -- internal
  48                         state_int <= SIDLE;
  49                         -- out
  50                         d_zeile_int <= (others => '0');
  51                         d_spalte_int <= (others => '0');
  52                         d_get_int <= '0';
  53                         command_int <= COMMAND_NOP;
  54                         command_data_int <= (others => '0');
  55                 elsif rising_edge(sys_clk) then
  56                         -- internal
  57                         state_int <= state_next;
  58                         -- out
  59                         d_zeile_int <= d_zeile_next;
  60                         d_spalte_int <= d_spalte_next;
  61                         d_get_int <= d_get_next;
  62                         command_int <= command_next;
  63                         command_data_int <= command_data_next;
  64                 end if;
  65         end process;
  66
  67         -- next state
  68         process(state_int, d_new_result, d_new_eingabe, d_done, free, d_spalte_int)
  69         begin
  70                 state_next <= state_int;
  71
  72                 case state_int is
  73                         when SIDLE =>
  74                                 if d_new_eingabe = '1' then
  75                                         state_next <= S_NEW_INPUT;
  76                                 end if;
  77                                 if d_new_result = '1' then
  78                                         state_next <= S_NEW_RESULT;
  79                                 end if;
  80                         when S_NEW_RESULT | S_NEW_INPUT =>
  81                                 state_next <= S_COUNTUP;
  82                         when S_COUNTUP =>
  83                                 state_next <= S_GETCH;
  84                         when S_GETCH =>
  85                                 if free = '1' and d_done = '1' then
  86                                         state_next <= S_PUTCH;
  87                                 end if;
  88                         when S_PUTCH =>
  89                                 if free = '0' then
  90                                         state_next <= S_WAIT;
  91                                 end if;
  92                         when S_WAIT =>
  93                                 if free = '1' and d_done = '0' then
  94                                         state_next <= S_NOP1;
  95                                 end if;
  96                         when S_NOP1 =>
  97                                 if free = '0' then
  98                                         state_next <= S_NOP2;
  99                                 end if;
 100                         when S_NOP2 =>
 101                                 if free = '1' then
 102                                         if unsigned(d_spalte_int) = 71 then
 103                                                 state_next <= SIDLE;
 104                                         else
 105                                                 state_next <= S_COUNTUP;
 106                                         end if;
 107                                 end if;
 108                 end case;
 109         end process;
 110
 111         -- out
 112         process(state_int, d_zeile_int, d_spalte_int, d_get_int, command_int,
 113                 command_data_int, d_char)
 114         begin
 115                 d_zeile_next <= d_zeile_int;
 116                 d_spalte_next <= d_spalte_int;
 117                 d_get_next <= '0';
 118                 command_next <= command_int;
 119                 command_data_next <= command_data_int;
 120
 121                 case state_int is
 122                         when SIDLE =>
 123                                 null;
 124                         when S_NEW_INPUT =>
 125                                 d_spalte_next <= (others => '0');
 126                         when S_NEW_RESULT =>
 127                                 d_spalte_next <= (others => '0');
 128                                 case d_zeile_int is
 129                                         when "11111" => d_zeile_next <= "00000";
 130                                         when others => d_zeile_next <= std_logic_vector(unsigned(d_zeile_int) + 1);
 131                                 end case;
 132                         when S_COUNTUP =>
 133                                 d_get_next <= '1';
 134                                 d_spalte_next <= std_logic_vector(unsigned(d_spalte_int) + 1);
 135                         when S_GETCH =>
 136                                 d_get_next <= '1';
 137                         when S_PUTCH =>
 138                                 command_next <= COMMAND_SET_CHAR;
 139                                 command_data_next <= x"000000" & std_logic_vector(d_char);
 140                         when S_WAIT | S_NOP2 =>
 141                                 null;
 142                         when S_NOP1 =>
 143                                 command_next <= COMMAND_NOP;
 144                                 command_data_next <= x"00000000";
 145                 end case;
 146         end process;
 147 end architecture beh;