Subversion Repositories modular_oscilloscope

--|------------------------------------------------------------------------------

--| UNSL - Modular Oscilloscope

--|

--| File: eppwbn_epp_side.vhd

--| Version: 0.01

--| Targeted device: Actel A3PE1500

--|------------------------------------------------------------------------------

--| Description:

--|     EPP - Wishbone bridge.

--|     EPP module output control (IEEE Std. 1284-2000).

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

--| File history:

--|     0.01    | nov-2008 | First release

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

--| Copyright ® 2008, Facundo Aguilera.

--|

--| This VHDL design file is an open design; you can redistribute it and/or

--| modify it and/or implement it after contacting the author.

library IEEE;

use IEEE.STD_LOGIC_1164.ALL;

entity eppwbn_epp_side is

port(

  -- Selección de modo

  epp_mode: in std_logic_vector (1 downto 0);-- indicador de modo de comunicación epp

    -- "00" deshabilitado

    -- "01" inicial (señales de usuario e interrupciones deshabilitadas)

    -- "10" sin definir

    -- "11" modo EPP normal

  -- CTRL signals

        ctr_nAck:   in std_logic;                  -- PtrClk/PeriphClk/Intr

        ctr_PError: in std_logic;                  -- AckData/nAckReverse

        ctr_Sel:    in std_logic;                  -- XFlag (Select). Select no puede usarse

        ctr_nFault: in std_logic;                  -- nDataAvail/nPeriphRequest

  ctr_nAutoFd:    out std_logic;               -- HostBusy/HostAck/nDStrb

        ctr_nSelectIn:  out std_logic;               -- 1284 Active/nAStrb

  ctr_nStrobe:    out std_logic;               -- HostClk/nWrite

        -- WB-side signals

        wb_Busy:       in std_logic;              -- PtrBusy/PeriphAck/nWait

  wb_nAutoFd:    out std_logic;               -- HostBusy/HostAck/nDStrb

        wb_nSelectIn:  out std_logic;               -- 1284 Active/nAStrb

        wb_nStrobe:    out std_logic;               -- HostClk/nWrite

    -- No están implementadas las señales personalizadas

  -- To EPP port

        nAck:   out std_logic;                  -- PtrClk/PeriphClk/Intr

        PError: out std_logic;                  -- AckData/nAckReverse

        Sel:    out std_logic;                  -- XFlag (Select). Select no puede usarse

        nFault: out std_logic;                  -- nDataAvail/nPeriphRequest

  Busy:      out std_logic;                 -- PtrBusy/PeriphAck/nWait

        nAutoFd:   in std_logic;                  -- HostBusy/HostAck/nDStrb

        nSelectIn: in std_logic;                  -- 1284 Active/nAStrb

        nStrobe:   in std_logic                  -- HostClk/nWrite

);

end entity eppwbn_epp_side;

architecture multiplexor of eppwbn_epp_side is

begin

  -- Puentes

  --  Son incorporados en un módulo para facilitar modificaciones

  ctr_nAutoFd <= nAutoFd;

  ctr_nSelectIn <= nSelectIn;

  ctr_nStrobe <= nStrobe;

  -- Selección de salidas desde el módulo EPP cuando epp_mode = "11"

  --  Como no están implementadas las señales personalizadas se escribe "0000"

  multiplexing: process (epp_mode ,ctr_nAck, ctr_PError, ctr_Sel, ctr_nFault,

                                                nAutoFd, nSelectIn, nStrobe, wb_Busy) begin

    case epp_mode is

      when "11" =>

        -- Hacia el host

        nAck <= '1'; -- No están implementadas las señales personalizadas

        PError <= '0';

        Sel <= '0';

        nFault <= '0';

        -- Hacia el módulo EPP

        wb_nAutoFd <= nAutoFd;

        wb_nSelectIn <= nSelectIn;

        wb_nStrobe <= nStrobe;

        Busy <= wb_Busy;

      when "01" =>

        -- Hacia el host

        nAck <= ctr_nAck;

        PError <= ctr_PError;

        Sel <= ctr_Sel;

        nFault <= ctr_nFault;

        -- Hacia el módulo EPP

        wb_nAutoFd <= nAutoFd;

        wb_nSelectIn <= nSelectIn;

        wb_nStrobe <= nStrobe;

        Busy <= wb_Busy;

      when others =>

        -- Hacia el host

        nAck <= ctr_nAck;

        PError <= ctr_PError;

        Sel <= ctr_Sel;

        nFault <= ctr_nFault;

        -- Hacia el módulo EPP

        wb_nAutoFd <= '1';

        wb_nSelectIn <= '1';

        wb_nStrobe <= '1';

        Busy <= '0';

    end case;

  end process;

end architecture multiplexor;