Subversion Repositories t400

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

--

-- $Id: t400_io_pack-p.vhd 179 2009-04-01 19:48:38Z arniml $

--

-- Copyright (c) 2006, Arnim Laeuger (arniml@opencores.org)

--

-- All rights reserved

--

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

library ieee;

use ieee.std_logic_1164.all;

package t400_io_pack is

  function io_out_f(dat : in std_logic;

                    opt : in integer) return std_logic;

  function io_en_f (en  : in std_logic;

                    dat : in std_logic;

                    opt : in integer) return std_logic;

end t400_io_pack;

use work.t400_opt_pack.all;

package body t400_io_pack is

  function io_out_f(dat : in std_logic;

                    opt : in integer) return std_logic is

    variable result_v : std_logic;

  begin

    result_v := '-';

    case opt is

      -- Open drain type output drivers ---------------------------------------

      when t400_opt_out_type_od_c  =>

        result_v := '0';

      -- Push/pull type output drivers ----------------------------------------

      when t400_opt_out_type_std_c |

           t400_opt_out_type_led_c |

           t400_opt_out_type_pp_c  =>

        result_v := dat;

      when others =>

        null;

    end case;

    return result_v;

  end io_out_f;

  function io_en_f (en  : in std_logic;

                    dat : in std_logic;

                    opt : in integer) return std_logic is

    variable result_v : std_logic;

  begin

    result_v := '0';

    case opt is

      -- Open drain type output drivers ---------------------------------------

      when t400_opt_out_type_od_c  =>

        if en = '1' and dat = '0' then

          result_v := '1';

        end if;

      -- Push/pull type output drivers ----------------------------------------

      when t400_opt_out_type_std_c |

           t400_opt_out_type_led_c |

           t400_opt_out_type_pp_c  =>

        result_v := en;

      when others =>

        null;

    end case;

    return result_v;

  end io_en_f;

end t400_io_pack;