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[/] [System09/] [trunk/] [rtl/] [Cyclone2/] [wb_lpm_rom.vhd] - Rev 221
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--===========================================================================-- -- -- S Y N T H E Z I A B L E Altera LPM_ROM / WISHBONE interface -- -- www.OpenCores.Org - August 2003 -- This core adheres to the GNU public license -- -- File name : wb_lpm_rom.vhd -- -- Purpose : Implements a WISHBONE compatble interface -- for the Altera LPM_ROM -- -- Dependencies : ieee.Std_Logic_1164 -- ieee.std_logic_unsigned -- work.lpm_components (Altera's 220PACK.vhd) -- -- Author : Michael L. Hasenfratz Sr. -- --===========================================================================---- -- -- Revision History: -- -- Date: Revision Author --===========================================================================-- -- 1 Aug 2003 0.1 Michael L. Hasenfratz Sr. -- Created -- library ieee; use ieee.std_logic_1164.all; use ieee.std_logic_unsigned.all; library lpm; use lpm.lpm_components.all; entity wb_lpm_rom is generic ( LPM_WIDTH : positive range 1 to 64 := 8; -- data bits WIDE LPM_WIDTHAD : positive range 1 to 32 := 8; -- address bits; LPM_FILE : string := "my_rom" -- ROM Data File ); port ( DAT_O : out std_logic_vector(LPM_WIDTH-1 downto 0); ADR_I : in std_logic_vector(LPM_WIDTHAD-1 downto 0); SEL_I : in std_logic_vector((LPM_WIDTH/8)-1 downto 0); STB_I : in std_logic; -- VMA (Valid Memory Access) CYC_I : in std_logic; -- CYC in progress ACK_O : out std_logic; -- Data ready CLK_I : in std_logic; -- System Clock RST_I : in std_logic -- Reset ); end; architecture bhv_wb_lpm_rom of wb_lpm_rom is signal iack : std_logic; -- Internal ACK signal isel : std_logic; -- device selected begin --------------------------------------------------------- -- Instantiate the ROM interface --------------------------------------------------------- rom0 : LPM_ROM generic map ( LPM_WIDTH => LPM_WIDTH, LPM_WIDTHAD => LPM_WIDTHAD, LPM_OUTDATA => "UNREGISTERED", LPM_FILE => LPM_FILE ) port map ( Q => DAT_O, ADDRESS => ADR_I, INCLOCK => CLK_I ); --------------------------------------------------------- -- Interconnections --------------------------------------------------------- ACK_O <= isel and iack; -- Selection romsel : process(SEL_I, CYC_I, STB_I) variable vsel : std_logic; begin vsel := '0'; for ndx in SEL_I'RANGE loop vsel := vsel or SEL_I(ndx); end loop; isel <= vsel and CYC_I and STB_I; end process; -- Read Acknowledge rdack : process(RST_I, CLK_I) begin if CLK_I'EVENT and CLK_I = '1' then if RST_I = '1' then iack <= '0'; elsif iack = '1' then iack <= '0'; else iack <= isel; end if; end if; end process; end bhv_wb_lpm_rom;
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