----------------------------------------------------------------------------------
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----------------------------------------------------------------------------------
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-- Company:
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-- Company:
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-- Engineer: Peter Fall
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-- Engineer: Peter Fall
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--
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--
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-- Create Date: 12:00:04 05/31/2011
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-- Create Date: 12:00:04 05/31/2011
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-- Design Name:
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-- Design Name:
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-- Module Name: arp_REQ - Behavioral
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-- Module Name: arp_REQ - Behavioral
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-- Project Name:
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-- Project Name:
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-- Target Devices:
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-- Target Devices:
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-- Tool versions:
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-- Tool versions:
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-- Description:
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-- Description:
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-- handle requests for ARP resolution
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-- handle requests for ARP resolution
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-- responds from single entry cache or searches external arp store, or asks to send a request
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-- responds from single entry cache or searches external arp store, or asks to send a request
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--
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--
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-- Dependencies:
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-- Dependencies:
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--
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--
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-- Revision:
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-- Revision:
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-- Revision 0.01 - File Created from arp.vhd 0.2
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-- Revision 0.01 - File Created from arp.vhd 0.2
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-- Additional Comments:
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-- Additional Comments:
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--
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--
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----------------------------------------------------------------------------------
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----------------------------------------------------------------------------------
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library IEEE;
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library IEEE;
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use IEEE.STD_LOGIC_1164.ALL;
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use IEEE.STD_LOGIC_1164.all;
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use IEEE.NUMERIC_STD.ALL;
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use IEEE.NUMERIC_STD.all;
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use work.arp_types.all;
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use work.arp_types.all;
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entity arp_req is
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entity arp_req is
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generic (
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generic (
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no_default_gateway : boolean := true; -- set to false if communicating with devices accessed
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-- through a "default gateway or router"
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CLOCK_FREQ : integer := 125000000; -- freq of data_in_clk -- needed to timout cntr
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CLOCK_FREQ : integer := 125000000; -- freq of data_in_clk -- needed to timout cntr
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ARP_TIMEOUT : integer := 60; -- ARP response timeout (s)
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ARP_TIMEOUT : integer := 60; -- ARP response timeout (s)
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ARP_MAX_PKT_TMO : integer := 5 -- # wrong nwk pkts received before set error
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ARP_MAX_PKT_TMO : integer := 5 -- # wrong nwk pkts received before set error
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);
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);
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Port (
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port (
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-- lookup request signals
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-- lookup request signals
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arp_req_req : in arp_req_req_type; -- request for a translation from IP to MAC
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arp_req_req : in arp_req_req_type; -- request for a translation from IP to MAC
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arp_req_rslt : out arp_req_rslt_type; -- the result
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arp_req_rslt : out arp_req_rslt_type; -- the result
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-- external arp store signals
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-- external arp store signals
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arp_store_req : out arp_store_rdrequest_t; -- requesting a lookup or store
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arp_store_req : out arp_store_rdrequest_t; -- requesting a lookup or store
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arp_store_result : in arp_store_result_t; -- the result
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arp_store_result : in arp_store_result_t; -- the result
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-- network request signals
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-- network request signals
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arp_nwk_req : out arp_nwk_request_t; -- requesting resolution via the network
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arp_nwk_req : out arp_nwk_request_t; -- requesting resolution via the network
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arp_nwk_result : in arp_nwk_result_t; -- the result
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arp_nwk_result : in arp_nwk_result_t; -- the result
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-- system signals
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-- system signals
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clear_cache : in std_logic; -- clear the internal cache
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clear_cache : in std_logic; -- clear the internal cache
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nwk_gateway : in std_logic_vector(31 downto 0); -- IP address of default gateway
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nwk_mask : in std_logic_vector(31 downto 0); -- Net mask
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clk : in std_logic;
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clk : in std_logic;
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reset : in STD_LOGIC
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reset : in std_logic
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);
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);
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end arp_req;
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end arp_req;
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architecture Behavioral of arp_req is
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architecture Behavioral of arp_req is
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type req_state_t is (IDLE,LOOKUP,WAIT_REPLY,PAUSE1,PAUSE2,PAUSE3);
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type req_state_t is (IDLE, LOOKUP, WAIT_REPLY, PAUSE1, PAUSE2, PAUSE3);
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type set_cntr_t is (HOLD,CLR,INCR);
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type set_cntr_t is (HOLD, CLR, INCR);
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type set_clr_type is (SET, CLR, HOLD);
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type set_clr_type is (SET, CLR, HOLD);
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-- state variables
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-- state variables
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signal req_state : req_state_t;
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signal req_state : req_state_t;
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signal req_ip_addr : std_logic_vector (31 downto 0); -- IP address to lookup
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signal req_ip_addr : std_logic_vector (31 downto 0); -- IP address to lookup
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signal arp_entry_cache : arp_entry_t; -- single entry cache for fast response
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signal arp_entry_cache : arp_entry_t; -- single entry cache for fast response
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signal cache_valid : std_logic; -- single entry cache is valid
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signal cache_valid : std_logic; -- single entry cache is valid
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signal nwk_rx_cntr : unsigned(7 downto 0); -- counts nwk rx pkts that dont satisfy
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signal nwk_rx_cntr : unsigned(7 downto 0); -- counts nwk rx pkts that dont satisfy
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signal freq_scaler : unsigned (31 downto 0); -- scales data_in_clk downto 1Hz
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signal freq_scaler : unsigned (31 downto 0); -- scales data_in_clk downto 1Hz
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signal timer : unsigned (7 downto 0); -- counts seconds timeout
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signal timer : unsigned (7 downto 0); -- counts seconds timeout
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signal timeout_reg : std_logic;
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signal timeout_reg : std_logic;
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-- busses
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-- busses
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signal next_req_state : req_state_t;
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signal next_req_state : req_state_t;
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signal arp_entry_val : arp_entry_t;
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signal arp_entry_val : arp_entry_t;
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-- requester control signals
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-- requester control signals
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signal set_req_state : std_logic;
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signal set_req_state : std_logic;
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signal set_req_ip : std_logic;
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signal set_req_ip : std_logic;
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signal store_arp_cache : std_logic;
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signal store_arp_cache : std_logic;
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signal set_nwk_rx_cntr : set_cntr_t;
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signal set_nwk_rx_cntr : set_cntr_t;
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signal set_timer : set_cntr_t; -- timer reset, count, hold control
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signal set_timer : set_cntr_t; -- timer reset, count, hold control
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signal timer_enable : std_logic; -- enable the timer counting
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signal timer_enable : std_logic; -- enable the timer counting
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signal set_timeout : set_clr_type; -- control the timeout register
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signal set_timeout : set_clr_type; -- control the timeout register
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signal clear_cache_valid : std_logic;
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signal clear_cache_valid : std_logic;
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signal l_arp_req_req_ip : std_logic_vector(31 downto 0); -- local network IP address for resolution
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begin
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begin
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default_GW: if (not no_default_gateway) generate
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default_gw_comb_p: process (arp_req_req.ip, nwk_gateway, nwk_mask) is
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begin -- process default_gw_comb_p
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-- translate IP addresses to local IP address if necessary
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if ((nwk_mask and arp_req_req.ip) = (nwk_mask and nwk_gateway)) then
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-- on local network
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l_arp_req_req_ip <= arp_req_req.ip;
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else
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-- on remote network
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l_arp_req_req_ip <= nwk_gateway;
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end if;
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end process default_gw_comb_p;
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end generate default_GW;
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no_default_GW: if (no_default_gateway) generate
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no_default_gw_comb_p: process (arp_req_req.ip) is
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begin -- process no_default_gw_comb_p
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l_arp_req_req_ip <= arp_req_req.ip;
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end process no_default_gw_comb_p;
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end generate no_default_GW;
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req_combinatorial : process (
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req_combinatorial : process (
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-- input signals
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arp_entry_cache.ip, arp_entry_cache.mac, arp_nwk_result.entry, arp_nwk_result.entry.ip,
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arp_req_req, arp_store_result, arp_nwk_result, clear_cache,
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arp_nwk_result.entry.mac, arp_nwk_result.status, arp_req_req.lookup_req,
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-- state variables
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arp_store_result.entry, arp_store_result.entry.mac, arp_store_result.status, cache_valid,
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req_state, req_ip_addr, arp_entry_cache, cache_valid, nwk_rx_cntr,
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clear_cache, freq_scaler, l_arp_req_req_ip, nwk_rx_cntr, req_ip_addr, req_state,
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freq_scaler, timer, timeout_reg,
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timeout_reg, timer)
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-- busses
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next_req_state, arp_entry_val,
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-- control signals
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set_req_state, set_req_ip, store_arp_cache, set_nwk_rx_cntr, clear_cache_valid,
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set_timer, timer_enable, set_timeout
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)
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begin
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begin
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-- set output followers
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-- set output followers
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arp_req_rslt.got_mac <= '0'; -- set initial value of request result outputs
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arp_req_rslt.got_mac <= '0'; -- set initial value of request result outputs
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arp_req_rslt.got_err <= '0';
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arp_req_rslt.got_err <= '0';
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arp_req_rslt.mac <= (others => '0');
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arp_req_rslt.mac <= (others => '0');
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arp_store_req.req <= '0';
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arp_store_req.req <= '0';
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arp_store_req.ip <= (others => '0');
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arp_store_req.ip <= (others => '0');
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arp_nwk_req.req <= '0';
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arp_nwk_req.req <= '0';
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arp_nwk_req.ip <= (others => '0');
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arp_nwk_req.ip <= (others => '0');
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-- zero time response to lookup request if already in cache
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-- zero time response to lookup request if already in cache
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if arp_req_req.lookup_req = '1' and arp_req_req.ip = arp_entry_cache.ip and cache_valid = '1' then
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if arp_req_req.lookup_req = '1' and l_arp_req_req_ip = arp_entry_cache.ip and cache_valid = '1' then
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arp_req_rslt.got_mac <= '1';
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arp_req_rslt.got_mac <= '1';
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arp_req_rslt.mac <= arp_entry_cache.mac;
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arp_req_rslt.mac <= arp_entry_cache.mac;
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elsif arp_req_req.lookup_req = '1' then
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elsif arp_req_req.lookup_req = '1' then
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-- hold off got_mac while req is there as arp_entry will not be correct yet
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-- hold off got_mac while req is there as arp_entry will not be correct yet
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arp_req_rslt.got_mac <= '0';
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arp_req_rslt.got_mac <= '0';
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arp_req_rslt.mac <= arp_entry_cache.mac;
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arp_req_rslt.mac <= arp_entry_cache.mac;
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else
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else
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arp_req_rslt.got_mac <= cache_valid;
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arp_req_rslt.got_mac <= cache_valid;
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arp_req_rslt.mac <= arp_entry_cache.mac;
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arp_req_rslt.mac <= arp_entry_cache.mac;
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end if;
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end if;
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if arp_req_req.lookup_req = '1' then
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if arp_req_req.lookup_req = '1' then
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-- ensure any existing error report is killed at the start of a request
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-- ensure any existing error report is killed at the start of a request
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arp_req_rslt.got_err <= '0';
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arp_req_rslt.got_err <= '0';
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else
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else
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arp_req_rslt.got_err <= timeout_reg;
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arp_req_rslt.got_err <= timeout_reg;
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end if;
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end if;
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-- set signal defaults
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-- set signal defaults
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next_req_state <= IDLE;
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next_req_state <= IDLE;
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set_req_state <= '0';
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set_req_state <= '0';
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set_req_ip <= '0';
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set_req_ip <= '0';
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store_arp_cache <= '0';
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store_arp_cache <= '0';
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arp_entry_val.ip <= (others => '0');
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arp_entry_val.ip <= (others => '0');
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arp_entry_val.mac <= (others => '0');
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arp_entry_val.mac <= (others => '0');
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set_nwk_rx_cntr <= HOLD;
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set_nwk_rx_cntr <= HOLD;
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set_timer <= INCR; -- default is timer running, unless we hold or reset it
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set_timer <= INCR; -- default is timer running, unless we hold or reset it
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set_timeout <= HOLD;
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set_timeout <= HOLD;
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timer_enable <= '0';
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timer_enable <= '0';
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clear_cache_valid <= clear_cache;
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clear_cache_valid <= clear_cache;
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-- combinatorial logic
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-- combinatorial logic
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if freq_scaler = x"00000000" then
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if freq_scaler = x"00000000" then
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timer_enable <= '1';
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timer_enable <= '1';
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end if;
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end if;
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-- REQ FSM
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-- REQ FSM
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case req_state is
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case req_state is
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when IDLE =>
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when IDLE =>
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set_timer <= CLR;
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set_timer <= CLR;
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if arp_req_req.lookup_req = '1' then
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if arp_req_req.lookup_req = '1' then
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-- check if we already have the info in cache
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-- check if we already have the info in cache
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if arp_req_req.ip = arp_entry_cache.ip and cache_valid = '1' then
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if l_arp_req_req_ip = arp_entry_cache.ip and cache_valid = '1' then
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-- already have this IP - feed output back
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-- already have this IP - feed output back
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arp_req_rslt.got_mac <= '1';
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arp_req_rslt.got_mac <= '1';
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arp_req_rslt.mac <= arp_entry_cache.mac;
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arp_req_rslt.mac <= arp_entry_cache.mac;
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else
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else
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clear_cache_valid <= '1'; -- remove cache entry
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clear_cache_valid <= '1'; -- remove cache entry
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set_timeout <= CLR;
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set_timeout <= CLR;
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next_req_state <= LOOKUP;
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next_req_state <= LOOKUP;
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set_req_state <= '1';
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set_req_state <= '1';
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set_req_ip <= '1';
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set_req_ip <= '1';
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end if;
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end if;
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end if;
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end if;
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when LOOKUP =>
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when LOOKUP =>
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-- put request on the store
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-- put request on the store
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arp_store_req.ip <= req_ip_addr;
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arp_store_req.ip <= req_ip_addr;
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arp_store_req.req <= '1';
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arp_store_req.req <= '1';
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case arp_store_result.status is
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case arp_store_result.status is
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when FOUND =>
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when FOUND =>
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-- update the cache
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-- update the cache
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arp_entry_val <= arp_store_result.entry;
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arp_entry_val <= arp_store_result.entry;
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store_arp_cache <= '1';
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store_arp_cache <= '1';
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-- and feed output back
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-- and feed output back
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arp_req_rslt.got_mac <= '1';
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arp_req_rslt.got_mac <= '1';
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arp_req_rslt.mac <= arp_store_result.entry.mac;
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arp_req_rslt.mac <= arp_store_result.entry.mac;
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next_req_state <= IDLE;
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next_req_state <= IDLE;
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set_req_state <= '1';
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set_req_state <= '1';
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when NOT_FOUND =>
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when NOT_FOUND =>
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-- need to request from the network
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-- need to request from the network
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set_timer <= CLR;
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set_timer <= CLR;
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set_nwk_rx_cntr <= CLR;
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set_nwk_rx_cntr <= CLR;
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arp_nwk_req.req <= '1';
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arp_nwk_req.req <= '1';
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arp_nwk_req.ip <= req_ip_addr;
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arp_nwk_req.ip <= req_ip_addr;
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next_req_state <= WAIT_REPLY;
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next_req_state <= WAIT_REPLY;
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set_req_state <= '1';
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set_req_state <= '1';
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when OTHERS =>
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when others =>
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-- just keep waiting - no timeout (assumes lookup with either succeed or fail)
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-- just keep waiting - no timeout (assumes lookup with either succeed or fail)
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end case;
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end case;
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when WAIT_REPLY =>
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when WAIT_REPLY =>
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case arp_nwk_result.status is
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case arp_nwk_result.status is
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when RECEIVED =>
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when RECEIVED =>
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if arp_nwk_result.entry.ip = req_ip_addr then
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-- store into cache
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-- store into cache
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arp_entry_val <= arp_nwk_result.entry;
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arp_entry_val <= arp_nwk_result.entry;
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store_arp_cache <= '1';
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store_arp_cache <= '1';
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-- and feed output back
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-- and feed output back
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if arp_nwk_result.entry.ip = req_ip_addr then
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arp_req_rslt.got_mac <= '1';
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arp_req_rslt.got_mac <= '1';
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arp_req_rslt.mac <= arp_nwk_result.entry.mac;
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arp_req_rslt.mac <= arp_nwk_result.entry.mac;
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next_req_state <= IDLE;
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next_req_state <= IDLE;
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set_req_state <= '1';
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set_req_state <= '1';
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else
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else
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if nwk_rx_cntr > ARP_MAX_PKT_TMO then
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if nwk_rx_cntr > ARP_MAX_PKT_TMO then
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set_timeout <= SET;
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set_timeout <= SET;
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next_req_state <= IDLE;
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next_req_state <= IDLE;
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set_req_state <= '1';
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set_req_state <= '1';
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else
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else
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set_nwk_rx_cntr <= INCR;
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set_nwk_rx_cntr <= INCR;
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end if;
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end if;
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end if;
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end if;
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when ERROR =>
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when error =>
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set_timeout <= SET;
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set_timeout <= SET;
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when OTHERS =>
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when others =>
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if timer >= ARP_TIMEOUT then
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if timer >= ARP_TIMEOUT then
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set_timeout <= SET;
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set_timeout <= SET;
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next_req_state <= PAUSE1;
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next_req_state <= PAUSE1;
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set_req_state <= '1';
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set_req_state <= '1';
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end if;
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end if;
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end case;
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end case;
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when PAUSE1 =>
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when PAUSE1 =>
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next_req_state <= PAUSE2;
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next_req_state <= PAUSE2;
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set_req_state <= '1';
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set_req_state <= '1';
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when PAUSE2 =>
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when PAUSE2 =>
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next_req_state <= PAUSE3;
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next_req_state <= PAUSE3;
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set_req_state <= '1';
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set_req_state <= '1';
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when PAUSE3 =>
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when PAUSE3 =>
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next_req_state <= IDLE;
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next_req_state <= IDLE;
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set_req_state <= '1';
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set_req_state <= '1';
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end case;
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end case;
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end process;
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end process;
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req_sequential : process (clk)
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req_sequential : process (clk)
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begin
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begin
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if rising_edge(clk) then
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if rising_edge(clk) then
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if reset = '1' then
|
if reset = '1' then
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-- reset state variables
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-- reset state variables
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req_state <= IDLE;
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req_state <= IDLE;
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req_ip_addr <= (others => '0');
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req_ip_addr <= (others => '0');
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arp_entry_cache.ip <= (others => '0');
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arp_entry_cache.ip <= (others => '0');
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arp_entry_cache.mac <= (others => '0');
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arp_entry_cache.mac <= (others => '0');
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cache_valid <= '0';
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cache_valid <= '0';
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nwk_rx_cntr <= (others => '0');
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nwk_rx_cntr <= (others => '0');
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freq_scaler <= to_unsigned(CLOCK_FREQ,32);
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freq_scaler <= to_unsigned(CLOCK_FREQ, 32);
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timer <= (others => '0');
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timer <= (others => '0');
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timeout_reg <= '0';
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timeout_reg <= '0';
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else
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else
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-- Next req_state processing
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-- Next req_state processing
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if set_req_state = '1' then
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if set_req_state = '1' then
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req_state <= next_req_state;
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req_state <= next_req_state;
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else
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else
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req_state <= req_state;
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req_state <= req_state;
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end if;
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end if;
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|
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-- Latch the requested IP address
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-- Latch the requested IP address
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if set_req_ip = '1' then
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if set_req_ip = '1' then
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req_ip_addr <= arp_req_req.ip;
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req_ip_addr <= l_arp_req_req_ip;
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else
|
else
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req_ip_addr <= req_ip_addr;
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req_ip_addr <= req_ip_addr;
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end if;
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end if;
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|
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-- network received counter
|
-- network received counter
|
case set_nwk_rx_cntr is
|
case set_nwk_rx_cntr is
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when CLR => nwk_rx_cntr <= (others => '0');
|
when CLR => nwk_rx_cntr <= (others => '0');
|
when INCR => nwk_rx_cntr <= nwk_rx_cntr + 1;
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when INCR => nwk_rx_cntr <= nwk_rx_cntr + 1;
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when HOLD => nwk_rx_cntr <= nwk_rx_cntr;
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when HOLD => nwk_rx_cntr <= nwk_rx_cntr;
|
end case;
|
end case;
|
|
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-- set the arp_entry_cache
|
-- set the arp_entry_cache
|
if clear_cache_valid = '1' then
|
if clear_cache_valid = '1' then
|
arp_entry_cache <= arp_entry_cache;
|
arp_entry_cache <= arp_entry_cache;
|
cache_valid <= '0';
|
cache_valid <= '0';
|
elsif store_arp_cache = '1' then
|
elsif store_arp_cache = '1' then
|
arp_entry_cache <= arp_entry_val;
|
arp_entry_cache <= arp_entry_val;
|
cache_valid <= '1';
|
cache_valid <= '1';
|
else
|
else
|
arp_entry_cache <= arp_entry_cache;
|
arp_entry_cache <= arp_entry_cache;
|
cache_valid <= cache_valid;
|
cache_valid <= cache_valid;
|
end if;
|
end if;
|
|
|
-- freq scaling and 1-sec timer
|
-- freq scaling and 1-sec timer
|
if freq_scaler = x"00000000" then
|
if freq_scaler = x"00000000" then
|
freq_scaler <= to_unsigned(CLOCK_FREQ,32);
|
freq_scaler <= to_unsigned(CLOCK_FREQ, 32);
|
else
|
else
|
freq_scaler <= freq_scaler - 1;
|
freq_scaler <= freq_scaler - 1;
|
end if;
|
end if;
|
|
|
-- timer processing
|
-- timer processing
|
case set_timer is
|
case set_timer is
|
when CLR =>
|
when CLR =>
|
timer <= x"00";
|
timer <= x"00";
|
when INCR =>
|
when INCR =>
|
if timer_enable = '1' then
|
if timer_enable = '1' then
|
timer <= timer + 1;
|
timer <= timer + 1;
|
else
|
else
|
timer <= timer;
|
timer <= timer;
|
end if;
|
end if;
|
when HOLD =>
|
when HOLD =>
|
timer <= timer;
|
timer <= timer;
|
end case;
|
end case;
|
|
|
-- timeout latching
|
-- timeout latching
|
case set_timeout is
|
case set_timeout is
|
when CLR => timeout_reg <= '0';
|
when CLR => timeout_reg <= '0';
|
when SET => timeout_reg <= '1';
|
when SET => timeout_reg <= '1';
|
when HOLD => timeout_reg <= timeout_reg;
|
when HOLD => timeout_reg <= timeout_reg;
|
end case;
|
end case;
|
|
|
end if;
|
end if;
|
end if;
|
end if;
|
end process;
|
end process;
|
|
|
end Behavioral;
|
end Behavioral;
|
|
|
