Subversion Repositories fade_ether_protocol

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

-- Title      : User command processor

-- Project    : 

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

-- File       : cmd_proc.vhd

-- Author     : Wojciech M. Zabolotny (wzab@ise.pw.edu.pl)

-- License    : BSD License

-- Company    : 

-- Created    : 2014-10-04

-- Last update: 2014-10-23

-- Platform   : 

-- Standard   : VHDL'93/02

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

-- Description: This block performs the user defined commands

--              but also generates responses for some internal commands.

--              

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

-- Copyright (c) 2014 

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

-- Revisions  :

-- Date        Version  Author  Description

-- 2014-10-04  1.0      WZab    Created

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

library ieee;

use ieee.std_logic_1164.all;

use ieee.numeric_std.all;

use std.textio.all;

library work;

use work.pkt_ack_pkg.all;

use work.desc_mgr_pkg.all;

use work.pkt_desc_pkg.all;

entity cmd_proc is

  port (

    cmd_code     : in  std_logic_vector(15 downto 0);

    cmd_seq      : in  std_logic_vector(15 downto 0);

    cmd_arg      : in  std_logic_vector(31 downto 0);

    cmd_run      : in  std_logic;

    cmd_ack      : out std_logic;

    cmd_response : out std_logic_vector(8*12-1 downto 0);

    clk          : in  std_logic;

    rst_p        : in  std_logic;

    -- Other inputs, needed to execute specific functions

    retr_count   : in std_logic_vector(31 downto 0)

    );

end entity cmd_proc;

architecture beh of cmd_proc is

  signal cmd_run_0, cmd_run_1, cmd_run_2 : std_logic               := '0';

  signal del_count                       : integer range 0 to 1000 := 0;

begin  -- architecture beh

  process (clk, rst_p) is

  begin  -- process

    if rst_p = '1' then                 -- asynchronous reset (active low)

      cmd_ack      <= '0';

      cmd_run_0    <= '0';

      cmd_run_1    <= '0';

      cmd_run_2    <= '0';

      del_count    <= 0;

      cmd_response <= (others => '0');

    elsif clk'event and clk = '1' then  -- rising clock edge

      -- Synchronize cmd_run signals

      cmd_run_2 <= cmd_run;

      cmd_run_1 <= cmd_run_2;

      cmd_run_0 <= cmd_run_1;

      -- Detect command strobe

      if cmd_run_1 /= cmd_run_0 then

        -- Line cmd_run has changed its state, it means that we need

        -- to execute a command

        if cmd_code(15 downto 8) = x"00" then

          -- For internal commands just send response immediately

          cmd_response <= cmd_code & cmd_seq &  -- This fields should be always

                                        -- sent on the begining of response!

                          x"00000000" & x"00000000";

          cmd_ack <= cmd_run;

        else

          -- Now we just simulate it, so let's start delay counter

          del_count <= 100;             -- execution of command takes 100 ckp

        end if;

      end if;

      -- We simulate execution of the user command, which was triggered by above

      -- "if" block

      if del_count > 0 then

        -- Decrease del_count until it is zero

        del_count <= del_count-1;

      end if;

      if del_count = 1 then

        -- Send response to the command:

        cmd_response <= cmd_code & cmd_seq &    -- This fields should be always

                                        -- sent on the begining of response!

                        cmd_arg & retr_count;

        cmd_ack <= cmd_run;

      end if;

    end if;

  end process;

end architecture beh;