pci_arb.tb

VHDLVERILOG语言实现的CARDBUS的IP源码,已经实现现场应用

--------------------------------------------------------------------------------
--
-- File : pci_arb.tb
-- Last Modification: 07/19/2001
--
-- Created In SpDE Version: SpDE 8.22
-- Author :	Richard Yuan, QuickLogic Corporation
-- Copyright (C) 2001, Licensed customers of QuickLogic may copy and modify
-- this file for use in designing with QuickLogic devices only.
--	
-- Description :
--	This is a PCI arbiter model.
--	Please see "The QL5064 PCI Bus Simulation Environment" for detailed informaiton.
--
-- Hierarchy:
--	The pci_arbiter entity is to be used in pci5(3/4)32_208.tb.
--
-- History:	
--	Date	        Author					Version
--  06/26/01		Richard Yuan			1.0
--		- Header reorganized to conform to coding standard.
--	07/19/01		Richard Yuan			1.1
--		- Initial value added for grant_device and search_device.
--------------------------------------------------------------------------------


--PARAMETER PCI_MASTER_DEVICES DEFAULT 1
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;

ENTITY pci_arbiter IS
         GENERIC (PCI_MASTER_DEVICES : integer := 1);
         PORT (
              pci_clk     : IN    std_logic;
              request_n     : IN std_logic_vector(PCI_MASTER_DEVICES-1 downto 0);
              grant_n     : OUT   std_logic_vector(PCI_MASTER_DEVICES-1 downto 0);
              busy     : IN    std_logic;
              reset_n     : IN    std_logic
         );
END pci_arbiter;

ARCHITECTURE pci_arbiter_ARC_CORE OF pci_arbiter IS

CONSTANT OUTPUT_DELAY : time := 2 NS;

--------Initial value signals
SIGNAL grant_reg   : std_logic_vector(PCI_MASTER_DEVICES-1 downto 0) := (others=>'0');

-- OUTPUT SIGNALS (TEMPS)
SIGNAL grant_n_outtmp   : std_logic_vector(PCI_MASTER_DEVICES-1 downto 0);

-- Wires -> SIGNALs
SIGNAL request   : std_logic_vector(PCI_MASTER_DEVICES-1 downto 0);
SIGNAL reset   : std_logic;

-- Regs -> SIGNALs
SIGNAL grant_device   : integer := 0;

BEGIN
-- The Assigns for the Output Vars
grant_n   <= grant_n_outtmp;

-- The Assigns for the temp Vars

--Beginning of actual code
reset <=  NOT reset_n;
grant_n_outtmp(PCI_MASTER_DEVICES-1 downto 0) <= (others=>'0') WHEN reset = '1' ELSE NOT grant_reg(PCI_MASTER_DEVICES-1 downto 0) after OUTPUT_DELAY;
request(PCI_MASTER_DEVICES-1 downto 0) <=  (others=>'Z') WHEN reset = '1' ELSE NOT request_n(PCI_MASTER_DEVICES-1 downto 0);

--ALWAYS: posedge pci_clk or posedge reset) begin if (reset) begin      grant_device <= 0
arbiter: PROCESS ( pci_clk, reset)
VARIABLE idle   : std_logic;
VARIABLE NEXT_DEVICE   : std_logic := '0';
VARIABLE search_device   : integer := 0;
VARIABLE jptempvar3   : std_logic;
BEGIN
   IF reset = '1'  THEN
      grant_device <= 0;
      idle := '0';
      grant_reg(PCI_MASTER_DEVICES-1 downto 1) <= (others=>'0');
      grant_reg(0) <= '1';
   --ADDED IF BELOW
   ELSIF rising_edge(pci_clk) THEN
      IF idle = '1' THEN
         grant_reg(grant_device) <=  '1';
         idle :=  '0';
      ELSE
         IF (NOT (request(grant_device))) = '1' THEN
            NEXT_DEVICE := '1';
         END IF;

-------jptempvar2 <= '1' WHEN grant_device = PCI_MASTER_DEVICES-1 ELSE '0';
         IF NEXT_DEVICE = '1'  THEN
            IF grant_device = PCI_MASTER_DEVICES-1 THEN
               search_device := 0;
            ELSE
               search_device := grant_device + 1;
            END IF;

-----jptempvar3 <=  '1' WHEN search_device = grant_device ELSE '0';
            IF search_device = grant_device THEN
               jptempvar3 := '1';
            ELSE jptempvar3 := '0'; 
            END IF;
            WHILE ((NOT request(search_device)) AND (NOT jptempvar3)) = '1' LOOP 
               IF (search_device = (PCI_MASTER_DEVICES - 1)) THEN
                   search_device := 0;
               ELSE
                   search_device := search_device + 1;
               END IF;
               IF search_device = grant_device THEN
                  jptempvar3 := '1';
               ELSE jptempvar3 := '0'; 
               END IF;
            END LOOP;

-----jptempvar3 <=  '1' WHEN search_device = grant_device ELSE '0';
            IF search_device = grant_device THEN
            ELSE
               NEXT_DEVICE := '0';
               grant_reg(grant_device) <= '0';
               grant_device <=  search_device;
               IF busy = '1' THEN
                  grant_reg(search_device) <=  '1';
               ELSE
                  idle :=  '1';
               END IF;
            END IF;
         END IF;
      END IF;
   END IF;
END PROCESS;
END pci_arbiter_ARC_CORE;