---------------------------------------------------------------------- ---- ---- ---- WISHBONE I2S Interface IP Core ---- ---- ---- ---- This file is part of the I2S Interface project ---- ---- http://www.opencores.org/cores/i2s_interface/ ---- ---- ---- ---- Description ---- ---- I2S encoder/decoder. ---- ---- ---- ---- ---- ---- To Do: ---- ---- - ---- ---- ---- ---- Author(s): ---- ---- - Geir Drange, gedra@opencores.org ---- ---- ---- ---------------------------------------------------------------------- ---- ---- ---- Copyright (C) 2004 Authors and OPENCORES.ORG ---- ---- ---- ---- This source file may be used and distributed without ---- ---- restriction provided that this copyright statement is not ---- ---- removed from the file and that any derivative work contains ---- ---- the original copyright notice and the associated disclaimer. ---- ---- ---- ---- This source file is free software; you can redistribute it ---- ---- and/or modify it under the terms of the GNU General ---- ---- Public License as published by the Free Software Foundation; ---- ---- either version 2.0 of the License, or (at your option) any ---- ---- later version. ---- ---- ---- ---- This source is distributed in the hope that it will be ---- ---- useful, but WITHOUT ANY WARRANTY; without even the implied ---- ---- warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ---- ---- PURPOSE. See the GNU General Public License for more details.---- ---- ---- ---- You should have received a copy of the GNU General ---- ---- Public License along with this source; if not, download it ---- ---- from http://www.gnu.org/licenses/gpl.txt ---- ---- ---- ---------------------------------------------------------------------- -- -- CVS Revision History -- -- $Log: not supported by cvs2svn $ -- Revision 1.3 2005/06/03 17:18:08 gedra -- BugFix: LSB of transmitted word would be set to zero in slave master mode. (Credit: Julien Dumont) -- -- Revision 1.2 2004/08/06 18:55:05 gedra -- Removed conf_inten, and fixed bug in transmitter master mode. -- -- Revision 1.1 2004/08/03 18:49:43 gedra -- I2S encoder/decoder. -- -- -- library ieee; use ieee.std_logic_1164.all; use ieee.numeric_std.all; entity i2s_codec is generic (DATA_WIDTH : integer; ADDR_WIDTH : integer; IS_MASTER : integer range 0 to 1; IS_RECEIVER : integer range 0 to 1); port ( wb_clk_i : in std_logic; -- wishbone clock conf_res : in std_logic_vector(5 downto 0); -- sample resolution conf_ratio : in std_logic_vector(7 downto 0); -- clock divider ratio conf_swap : in std_logic; -- left/right sample order conf_en : in std_logic; -- transmitter/recevier enable i2s_sd_i : in std_logic; -- I2S serial data input i2s_sck_i : in std_logic; -- I2S clock input i2s_ws_i : in std_logic; -- I2S word select input sample_dat_i : in std_logic_vector(DATA_WIDTH - 1 downto 0); -- audio data sample_dat_o : out std_logic_vector(DATA_WIDTH - 1 downto 0); -- audio data mem_rdwr : out std_logic; -- sample buffer read/write sample_addr : out std_logic_vector(ADDR_WIDTH - 2 downto 0); -- address evt_hsbf : out std_logic; -- higher sample buf empty event evt_lsbf : out std_logic; -- lower sample buf empty event i2s_sd_o : out std_logic; -- I2S serial data output i2s_sck_o : out std_logic; -- I2S clock output i2s_ws_o : out std_logic); -- I2S word select output end i2s_codec; architecture rtl of i2s_codec is signal i2s_clk_en, zsck, zzsck, zzzsck, imem_rd : std_logic; signal clk_cnt : integer range 0 to 255; signal adr_cnt : integer range 0 to 2**(ADDR_WIDTH - 1) - 1; type srx_states is (IDLE, WAIT_CLK, TRX_DATA, RX_WRITE, SYNC); signal sd_ctrl : srx_states; signal bit_cnt, bits_to_trx : integer range 0 to 63; signal toggle, master, neg_edge, ws_pos_edge, ws_neg_edge : std_logic; signal data_in : std_logic_vector(DATA_WIDTH - 1 downto 0); signal zws, zzws, zzzws, i2s_ws, new_word, last_bit : std_logic; signal imem_rdwr, receiver : std_logic; signal ws_cnt : integer range 0 to 31; begin -- Create signals that reflect generics SGM : if IS_MASTER = 1 generate master <= '1'; end generate SGM; SGS : if IS_MASTER = 0 generate master <= '0'; end generate SGS; SGRX : if IS_RECEIVER = 1 generate receiver <= '1'; end generate SGRX; SGTX : if IS_RECEIVER = 0 generate receiver <= '0'; end generate SGTX; -- I2S clock enable generation, master mode. The clock is a fraction of the -- Wishbone bus clock, determined by the conf_ratio value. CGM : if IS_MASTER = 1 generate CGEN : process (wb_clk_i) begin if rising_edge(wb_clk_i) then if conf_en = '0' then -- disabled i2s_clk_en <= '0'; clk_cnt <= 0; neg_edge <= '0'; toggle <= '0'; else -- enabled if clk_cnt < to_integer(unsigned(conf_ratio)) + 1 then clk_cnt <= (clk_cnt + 1) mod 256; i2s_clk_en <= '0'; else clk_cnt <= 0; i2s_clk_en <= '1'; neg_edge <= not neg_edge; end if; toggle <= neg_edge; end if; end if; end process CGEN; end generate CGM; -- I2S clock enable generation, slave mode. The input clock signal is sampeled -- and the negative edge is located. CGS : if IS_MASTER = 0 generate CGEN : process (wb_clk_i) begin if rising_edge(wb_clk_i) then if conf_en = '0' then -- disabled i2s_clk_en <= '0'; zsck <= '0'; zzsck <= '0'; zzzsck <= '0'; toggle <= '0'; neg_edge <= '0'; else -- enabled -- synchronize input clock to Wishbone clock domaine zsck <= i2s_sck_i; zzsck <= zsck; zzzsck <= zzsck; -- look for edges if zzzsck = '1' and zzsck = '0' then i2s_clk_en <= '1'; neg_edge <= '1'; elsif zzzsck = '0' and zzsck = '1' then i2s_clk_en <= '1'; neg_edge <= '0'; else i2s_clk_en <= '0'; end if; toggle <= neg_edge; end if; end if; end process CGEN; end generate CGS; -- Process to generate word select signal, master mode WSM : if IS_MASTER = 1 generate i2s_ws_o <= i2s_ws; WSG : process (wb_clk_i) begin if rising_edge(wb_clk_i) then if conf_en = '0' then i2s_ws <= '0'; ws_cnt <= 0; ws_pos_edge <= '0'; ws_neg_edge <= '0'; else if i2s_clk_en = '1' and toggle = '1' then if ws_cnt < bits_to_trx then ws_cnt <= ws_cnt + 1; else i2s_ws <= not i2s_ws; ws_cnt <= 0; if i2s_ws = '1' then ws_neg_edge <= '1'; else ws_pos_edge <= '1'; end if; end if; else ws_pos_edge <= '0'; ws_neg_edge <= '0'; end if; end if; end if; end process WSG; end generate WSM; -- Process to detect word select edges, slave mode WSD : if IS_MASTER = 0 generate i2s_ws <= i2s_ws_i; WSDET : process (wb_clk_i) begin if rising_edge(wb_clk_i) then if conf_en = '0' then ws_pos_edge <= '0'; ws_neg_edge <= '0'; zws <= i2s_ws; zzws <= i2s_ws; zzzws <= i2s_ws; else -- sync i2s_ws_io to our clock domaine zws <= i2s_ws; zzws <= zws; zzzws <= zzws; -- detect negative edge if zzzws = '1' and zzws = '0' then ws_neg_edge <= '1'; else ws_neg_edge <= '0'; end if; -- detect positive edge if zzzws = '0' and zzws = '1' then ws_pos_edge <= '1'; else ws_pos_edge <= '0'; end if; end if; end if; end process WSDET; end generate WSD; -- Logic to generate clock signal, master mode SCKM : if IS_MASTER = 1 generate i2s_sck_o <= toggle; end generate SCKM; -- Process to receive data on i2s_sd_i, or transmit data on i2s_sd_o sample_addr <= std_logic_vector(to_unsigned(adr_cnt, ADDR_WIDTH - 1)); mem_rdwr <= imem_rdwr; sample_dat_o <= data_in; SDRX : process (wb_clk_i) begin if rising_edge(wb_clk_i) then if conf_en = '0' then -- codec disabled imem_rdwr <= '0'; sd_ctrl <= IDLE; data_in <= (others => '0'); bit_cnt <= 0; bits_to_trx <= 0; new_word <= '0'; last_bit <= '0'; adr_cnt <= 0; evt_lsbf <= '0'; evt_hsbf <= '0'; i2s_sd_o <= '0'; else case sd_ctrl is when IDLE => imem_rdwr <= '0'; if to_integer(unsigned(conf_res)) > 15 and to_integer(unsigned(conf_res)) < 33 then bits_to_trx <= to_integer(unsigned(conf_res)) - 1; else bits_to_trx <= 15; end if; if conf_en = '1' then if (ws_pos_edge = '1' and conf_swap = '1') or (ws_neg_edge = '1' and conf_swap = '0') then if receiver = '1' then -- recevier sd_ctrl <= WAIT_CLK; else imem_rdwr <= '1'; -- read first data if transmitter sd_ctrl <= TRX_DATA; end if; end if; end if; when WAIT_CLK => -- wait for first bit after WS adr_cnt <= 0; bit_cnt <= 0; new_word <= '0'; last_bit <= '0'; data_in <= (others => '0'); if i2s_clk_en = '1' and neg_edge = '0' then sd_ctrl <= TRX_DATA; end if; when TRX_DATA => -- transmit/receive serial data imem_rdwr <= '0'; evt_hsbf <= '0'; evt_lsbf <= '0'; if master = '0' then if zzzws /= zzws then new_word <= '1'; end if; else if ws_pos_edge = '1' or ws_neg_edge = '1' then new_word <= '1'; end if; end if; if new_word = '1' and i2s_clk_en = '1' and neg_edge = '0' then last_bit <= '1'; end if; -- recevier operation if receiver = '1' then if i2s_clk_en = '1' and neg_edge = '1' then if master = '1' then -- master mode if bit_cnt < bits_to_trx and new_word = '0' then bit_cnt <= bit_cnt + 1; data_in(bits_to_trx - bit_cnt) <= i2s_sd_i; else imem_rdwr <= '1'; data_in(bits_to_trx - bit_cnt) <= i2s_sd_i; sd_ctrl <= RX_WRITE; end if; else -- slave mode if bit_cnt <= bits_to_trx and new_word = '0' then bit_cnt <= bit_cnt + 1; data_in(bits_to_trx - bit_cnt) <= i2s_sd_i; else data_in(bits_to_trx - bit_cnt) <= i2s_sd_i; imem_rdwr <= '1'; sd_ctrl <= RX_WRITE; end if; end if; end if; end if; -- transmitter operation if receiver = '0' then if master = '1' then -- master mode if i2s_clk_en = '1' and neg_edge = '0' then if bit_cnt < bits_to_trx and new_word = '0' then bit_cnt <= bit_cnt + 1; i2s_sd_o <= sample_dat_i(bits_to_trx - bit_cnt); else bit_cnt <= bit_cnt + 1; if bit_cnt > bits_to_trx then i2s_sd_o <= '0'; else i2s_sd_o <= sample_dat_i(0); end if; -- transmitter address counter imem_rdwr <= '1'; adr_cnt <= (adr_cnt + 1) mod 2**(ADDR_WIDTH - 1); if adr_cnt = 2**(ADDR_WIDTH - 2) - 1 then evt_lsbf <= '1'; else evt_lsbf <= '0'; end if; if adr_cnt = 2**(ADDR_WIDTH - 1) - 1 then evt_hsbf <= '1'; else evt_hsbf <= '0'; end if; sd_ctrl <= SYNC; end if; end if; else -- slave mode if i2s_clk_en = '1' and neg_edge = '1' then if bit_cnt < bits_to_trx and new_word = '0' then bit_cnt <= bit_cnt + 1; i2s_sd_o <= sample_dat_i(bits_to_trx - bit_cnt); else bit_cnt <= bit_cnt + 1; if bit_cnt > bits_to_trx then i2s_sd_o <= '0'; else i2s_sd_o <= sample_dat_i(bits_to_trx - bit_cnt); end if; if new_word = '1' then -- transmitter address counter imem_rdwr <= '1'; adr_cnt <= (adr_cnt + 1) mod 2**(ADDR_WIDTH - 1); if adr_cnt = 2**(ADDR_WIDTH - 2) - 1 then evt_lsbf <= '1'; else evt_lsbf <= '0'; end if; if adr_cnt = 2**(ADDR_WIDTH - 1) - 1 then evt_hsbf <= '1'; else evt_hsbf <= '0'; end if; sd_ctrl <= SYNC; end if; end if; end if; end if; end if; when RX_WRITE => -- write received word to sample buffer imem_rdwr <= '0'; adr_cnt <= (adr_cnt + 1) mod 2**(ADDR_WIDTH - 1); if adr_cnt = 2**(ADDR_WIDTH - 2) - 1 then evt_lsbf <= '1'; else evt_lsbf <= '0'; end if; if adr_cnt = 2**(ADDR_WIDTH - 1) - 1 then evt_hsbf <= '1'; else evt_hsbf <= '0'; end if; sd_ctrl <= SYNC; when SYNC => -- synchronise with next word imem_rdwr <= '0'; evt_hsbf <= '0'; evt_lsbf <= '0'; bit_cnt <= 0; if ws_pos_edge = '1' or ws_neg_edge = '1' then new_word <= '1'; end if; if new_word = '1' and i2s_clk_en = '1' and neg_edge = '0' then last_bit <= '1'; end if; if receiver = '1' then -- receive mode if master = '1' then new_word <= '0'; last_bit <= '0'; data_in <= (others => '0'); sd_ctrl <= TRX_DATA; else if i2s_clk_en = '1' and neg_edge = '0' and new_word = '1' then new_word <= '0'; last_bit <= '0'; data_in <= (others => '0'); sd_ctrl <= TRX_DATA; end if; end if; else -- transmit mode if master = '1' then new_word <= '0'; last_bit <= '0'; data_in <= (others => '0'); sd_ctrl <= TRX_DATA; elsif i2s_clk_en = '1' and neg_edge = '0' then new_word <= '0'; last_bit <= '0'; data_in <= (others => '0'); sd_ctrl <= TRX_DATA; end if; end if; when others => null; end case; end if; end if; end process SDRX; end rtl;