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gedra |
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---- ----
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---- WISHBONE I2S Interface IP Core ----
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---- ----
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---- This file is part of the I2S Interface project ----
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---- http://www.opencores.org/cores/i2s_interface/ ----
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---- ----
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---- Description ----
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---- I2S transmitter Wishbone bus cycle decoder. ----
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---- ----
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---- ----
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---- To Do: ----
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---- - ----
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---- ----
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---- Author(s): ----
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---- - Geir Drange, gedra@opencores.org ----
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---- ----
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----------------------------------------------------------------------
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---- ----
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---- Copyright (C) 2004 Authors and OPENCORES.ORG ----
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---- ----
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---- This source file may be used and distributed without ----
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---- restriction provided that this copyright statement is not ----
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---- removed from the file and that any derivative work contains ----
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---- the original copyright notice and the associated disclaimer. ----
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---- ----
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---- This source file is free software; you can redistribute it ----
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---- and/or modify it under the terms of the GNU General ----
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---- Public License as published by the Free Software Foundation; ----
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---- either version 2.0 of the License, or (at your option) any ----
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---- later version. ----
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---- ----
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---- This source is distributed in the hope that it will be ----
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---- useful, but WITHOUT ANY WARRANTY; without even the implied ----
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---- warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ----
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---- PURPOSE. See the GNU General Public License for more details.----
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---- ----
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---- You should have received a copy of the GNU General ----
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---- Public License along with this source; if not, download it ----
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---- from http://www.gnu.org/licenses/gpl.txt ----
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---- ----
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----------------------------------------------------------------------
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--
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-- CVS Revision History
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--
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-- $Log: not supported by cvs2svn $
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--
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--
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library ieee;
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use ieee.std_logic_1164.all;
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use ieee.numeric_std.all;
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entity tx_i2s_wbd is
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generic (DATA_WIDTH: integer;
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ADDR_WIDTH: integer);
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port (
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wb_clk_i: in std_logic; -- wishbone clock
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wb_rst_i: in std_logic; -- reset signal
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wb_sel_i: in std_logic; -- select input
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wb_stb_i: in std_logic; -- strobe input
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wb_we_i: in std_logic; -- write enable
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wb_cyc_i: in std_logic; -- cycle input
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wb_bte_i: in std_logic_vector(1 downto 0); -- burts type extension
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wb_cti_i: in std_logic_vector(2 downto 0); -- cycle type identifier
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wb_adr_i: in std_logic_vector(ADDR_WIDTH - 1 downto 0); -- address
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data_out: in std_logic_vector(DATA_WIDTH - 1 downto 0); -- internal bus
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wb_ack_o: out std_logic; -- acknowledge
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wb_dat_o: out std_logic_vector(DATA_WIDTH - 1 downto 0); -- data out
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version_rd: out std_logic; -- Version register read
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config_rd: out std_logic; -- Config register read
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config_wr: out std_logic; -- Config register write
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intmask_rd: out std_logic; -- Interrupt mask register read
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intmask_wr: out std_logic; -- Interrupt mask register write
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intstat_rd: out std_logic; -- Interrupt status register read
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intstat_wr: out std_logic; -- Interrupt status register read
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mem_wr: out std_logic); -- Sample memory write
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end tx_i2s_wbd;
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architecture rtl of tx_i2s_wbd is
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constant REG_TXVERSION : std_logic_vector(3 downto 0) := "0000";
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constant REG_TXCONFIG : std_logic_vector(3 downto 0) := "0001";
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constant REG_TXINTMASK : std_logic_vector(3 downto 0) := "0010";
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constant REG_TXINTSTAT : std_logic_vector(3 downto 0) := "0011";
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signal iack, iwr, ird : std_logic;
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signal acnt: integer range 0 to 2**(ADDR_WIDTH - 1) - 1;
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signal rdout : std_logic_vector(DATA_WIDTH - 1 downto 0);
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begin
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wb_ack_o <= iack;
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-- acknowledge generation
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ACK: process (wb_clk_i, wb_rst_i)
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begin
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if wb_rst_i = '1' then
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iack <= '0';
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elsif rising_edge(wb_clk_i) then
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if wb_cyc_i = '1' and wb_sel_i = '1' and wb_stb_i = '1' then
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case wb_cti_i is
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when "010" => -- incrementing burst
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case wb_bte_i is -- burst extension
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when "00" => -- linear burst
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iack <= '1';
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when others => -- all other treated assert classic cycle
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iack <= not iack;
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end case;
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when "111" => -- end of burst
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iack <= not iack;
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when others => -- all other treated assert classic cycle
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iack <= not iack;
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end case;
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else
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iack <= '0';
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end if;
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end if;
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end process ACK;
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-- write generation
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WR: process (wb_clk_i, wb_rst_i)
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begin
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if wb_rst_i = '1' then
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iwr <= '0';
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elsif rising_edge(wb_clk_i) then
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if wb_cyc_i = '1' and wb_sel_i = '1' and wb_stb_i = '1' and
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wb_we_i = '1' then
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case wb_cti_i is
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when "010" => -- incrementing burst
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case wb_bte_i is -- burst extension
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when "00" => -- linear burst
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iwr <= '1';
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when others => -- all other treated as classic cycle
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iwr <= not iwr;
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end case;
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when "111" => -- end of burst
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iwr <= not iwr;
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when others => -- all other treated as classic cycle
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iwr <= not iwr;
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end case;
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else
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iwr <= '0';
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end if;
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end if;
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end process WR;
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-- read generation
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ird <= '1' when wb_cyc_i = '1' and wb_sel_i = '1' and wb_stb_i = '1' and
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wb_we_i = '0' else '0';
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wb_dat_o <= data_out when wb_adr_i(ADDR_WIDTH - 1) = '1' else rdout;
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DREG: process (wb_clk_i) -- clock data from registers
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begin
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if rising_edge(wb_clk_i) then
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rdout <= data_out;
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end if;
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end process DREG;
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-- read and write strobe generation
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version_rd <= '1' when wb_adr_i(3 downto 0) = REG_TXVERSION and ird = '1'
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else '0';
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config_rd <= '1' when wb_adr_i(3 downto 0) = REG_TXCONFIG and ird = '1'
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else '0';
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config_wr <= '1' when wb_adr_i(3 downto 0) = REG_TXCONFIG and iwr = '1'
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else '0';
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intmask_rd <= '1' when wb_adr_i(3 downto 0) = REG_TXINTMASK and ird = '1'
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else '0';
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intmask_wr <= '1' when wb_adr_i(3 downto 0) = REG_TXINTMASK and iwr = '1'
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else '0';
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intstat_rd <= '1' when wb_adr_i(3 downto 0) = REG_TXINTSTAT and ird = '1'
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else '0';
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intstat_wr <= '1' when wb_adr_i(3 downto 0) = REG_TXINTSTAT and iwr = '1'
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else '0';
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mem_wr <= '1' when wb_adr_i(ADDR_WIDTH - 1) = '1' and iwr = '1' else '0';
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end rtl;
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