Subversion Repositories modular_oscilloscope

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--| Modular Oscilloscope

--| UNSL - Argentine

--|

--| File: dual_port_memory_wb.vhd

--| Version: 0.1

--| Tested in: Actel A3PE1500

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

--| Description:

--|   MEMORY - Dual Port Memory Wishbone Interface

--|   An interface designed for a dual port memory generated by Actel SmartGen tool. It may not work 

--|   with other than ProASIC3 Family FPGA.

--|   

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

--| File history:

--|   0.1   | jun-2009 | First testing

--|   0.11  | aug-2009 | Corrected error in ACK_O from port B

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

--| Copyright © 2009, 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.

--| Wishbone Rev. B.3 compatible

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

-- La memoria solo puede accederse desde la dirección 0 hasta la 15360 (0011 11000 0000 0000). No 

-- están especificados los valores obtenidos fuera de ese rango. 

library ieee;

use ieee.std_logic_1164.all;

entity dual_port_memory_wb is

        port(

                -- Puerto A (Higer prioriry)

                RST_I_a: in std_logic;

                CLK_I_a: in std_logic;

                DAT_I_a: in std_logic_vector (15 downto 0);

                DAT_O_a: out std_logic_vector (15 downto 0);

                ADR_I_a: in std_logic_vector (13 downto 0);

                CYC_I_a: in std_logic;

                STB_I_a: in std_logic;

                ACK_O_a: out std_logic ;

                WE_I_a: in std_logic;

    -- Puerto B (Lower prioriry)

                RST_I_b: in std_logic;

                CLK_I_b: in std_logic;

                DAT_I_b: in std_logic_vector (15 downto 0);

                DAT_O_b: out std_logic_vector (15 downto 0);

                ADR_I_b: in std_logic_vector (13 downto 0);

                CYC_I_b: in std_logic;

                STB_I_b: in std_logic;

                ACK_O_b: out std_logic ;

                WE_I_b: in std_logic

        );

end entity dual_port_memory_wb;

architecture arch01  of dual_port_memory_wb is

        ---- Componentes ----

  component dual_port_memory is

    port(

      DINA:   in    std_logic_vector(15 downto 0);

      DOUTA:  out   std_logic_vector(15 downto 0);

      ADDRA:  in    std_logic_vector(13 downto 0);  -- Only available up to 15360 (11110000000000)

      RWA:    in    std_logic;                      -- '1' Read, '0' Write

      BLKA:   in    std_logic;                      -- '1' Block select

      CLKA:   in    std_logic;                      -- Rising edge

      DINB:   in    std_logic_vector(15 downto 0);

      DOUTB:  out   std_logic_vector(15 downto 0);

      ADDRB:  in    std_logic_vector(13 downto 0);

      RWB:    in    std_logic;

      BLKB:   in    std_logic;

      CLKB:   in    std_logic;

      RESET:  in    std_logic                       -- '1' Reset

    ) ;

        end component dual_port_memory;

  ---- Señales ----

        signal RST_I_common: std_logic;

  signal enable_BLK, to_BLKB, to_BLKA : std_logic;

  signal pre_ACK_O_a_read, pre_ACK_O_a_write: std_logic;

  signal pre_ACK_O_b_read, pre_ACK_O_b_write: std_logic;

  signal to_RWB, to_RWA: std_logic; -- para entradas negadas

begin

  RST_I_common <= RST_I_b or RST_I_a;

  -- Corrección de escritura en la misma dirección

  to_BLKB <= CYC_I_b and STB_I_b and enable_BLK;

  to_BLKA <= CYC_I_a and STB_I_a;

  enable_BLK <= '1' when ADR_I_a /= ADR_I_b or to_BLKA = '0' else

                '0';

  -- Solución de ACK en puerto A

  ACK_O_a <= pre_ACK_O_a_write or pre_ACK_O_a_read;

  pre_ACK_O_a_write <= STB_I_a and CYC_I_a and WE_I_a;

    -- la primera respuesta para el ciclo de lectura debe retrasarse un ciclo

  P_ACK_a_resolution: process (STB_I_a, CYC_I_a, RST_I_a, CLK_I_a, WE_I_a)

  begin

    if STB_I_a = '0' or CYC_I_a = '0' then

      pre_ACK_O_a_read <= '0';

    elsif CLK_I_a'event and CLK_I_a = '1' then

      if RST_I_a = '1' then

        pre_ACK_O_a_read <= '0';

      elsif STB_I_a = '1' and CYC_I_a = '1' and WE_I_a = '0' then

        pre_ACK_O_a_read <= '1';

      end if;

    end if;

  end process;

   -- Solución de ACK en puerto B

  ACK_O_b <= (pre_ACK_O_b_write or pre_ACK_O_b_read) and enable_BLK;

  pre_ACK_O_b_write <= STB_I_b and CYC_I_b and WE_I_b;

    -- la primera respuesta para el ciclo de lectura debe retrasarse un ciclo

  P_ACK_b_resolution: process (STB_I_b, CYC_I_b, RST_I_b, CLK_I_b)

  begin

    if STB_I_b = '0' or CYC_I_b = '0' then

      pre_ACK_O_b_read <= '0';

    elsif CLK_I_b'event and CLK_I_b = '1' then

      if RST_I_b = '1' then

        pre_ACK_O_b_read <= '0';

      elsif STB_I_b = '1' and CYC_I_b = '1' and WE_I_b = '0'  then

        pre_ACK_O_b_read <= '1';

      end if;

    end if;

  end process;

  -- Instancia

  to_RWA <= not(WE_I_a);

  to_RWB <= not(WE_I_b);

        MEM: dual_port_memory port map (

                        DINA => DAT_I_a,

                        DOUTA => DAT_O_a,

                        ADDRA => ADR_I_a,

                        RWA => to_RWA,

                        BLKA => to_BLKA,

                        CLKA => CLK_I_a,

                        DINB => DAT_I_b,

                        DOUTB => DAT_O_b,

                        ADDRB => ADR_I_b,

                        RWB => to_RWB,

                        BLKB => to_BLKB,

                        CLKB => CLK_I_b,

                        RESET => RST_I_common

        );

end architecture;