pluto_hdl_adi/library/axi_spdif_rx/rx_cap_reg.vhd

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----------------------------------------------------------------------
---- ----
---- WISHBONE SPDIF IP Core ----
---- ----
---- This file is part of the SPDIF project ----
---- http://www.opencores.org/cores/spdif_interface/ ----
---- ----
---- Description ----
---- SPDIF receiver channel status capture module ----
---- ----
---- ----
---- 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 Lesser General ----
---- Public License as published by the Free Software Foundation; ----
---- either version 2.1 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 Lesser General Public License for more ----
---- details. ----
---- ----
---- You should have received a copy of the GNU Lesser General ----
---- Public License along with this source; if not, download it ----
---- from http://www.opencores.org/lgpl.shtml ----
---- ----
----------------------------------------------------------------------
--
-- CVS Revision History
--
-- $Log: not supported by cvs2svn $
-- Revision 1.4 2004/07/19 16:58:37 gedra
-- Fixed bug.
--
-- Revision 1.3 2004/06/27 16:16:55 gedra
-- Signal renaming and bug fix.
--
-- Revision 1.2 2004/06/26 14:14:47 gedra
-- Converted to numeric_std and fixed a few bugs.
--
-- Revision 1.1 2004/06/05 17:16:46 gedra
-- Channel status/user data capture register
--
--
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use work.rx_package.all;
entity rx_cap_reg is
port (
clk: in std_logic; -- clock
rst: in std_logic; -- reset
--cap_ctrl_wr: in std_logic; -- control register write
--cap_ctrl_rd: in std_logic; -- control register read
--cap_data_rd: in std_logic; -- data register read
cap_reg: in std_logic_vector(31 downto 0);
cap_din: in std_logic_vector(31 downto 0); -- write data
rx_block_start: in std_logic; -- start of block signal
ch_data: in std_logic; -- channel status/user data
ud_a_en: in std_logic; -- user data ch. A enable
ud_b_en: in std_logic; -- user data ch. B enable
cs_a_en: in std_logic; -- channel status ch. A enable
cs_b_en: in std_logic; -- channel status ch. B enable
cap_dout: out std_logic_vector(31 downto 0); -- read data
cap_evt: out std_logic); -- capture event (interrupt)
end rx_cap_reg;
architecture rtl of rx_cap_reg is
signal cap_ctrl_bits, cap_ctrl_dout: std_logic_vector(31 downto 0);
signal cap_reg_1, cap_new : std_logic_vector(31 downto 0);
signal bitlen, cap_len : integer range 0 to 63;
signal bitpos, cur_pos : integer range 0 to 255;
signal chid, cdata, compared : std_logic;
signal d_enable : std_logic_vector(3 downto 0);
begin
-- Data bus or'ing
cap_dout <= cap_reg_1;-- when cap_data_rd = '1' else cap_ctrl_dout;
chid <= cap_reg(6);
cdata <= cap_reg(7);
-- capture data register
CDAT: process (clk, rst)
begin
if rst = '1' then
cap_reg_1 <= (others => '0'); --
cap_new <= (others => '0');
cur_pos <= 0;
cap_len <= 0;
cap_evt <= '0';
compared <= '0';
bitpos <= 0;
bitlen <= 0;
else
if rising_edge(clk) then
bitlen <= to_integer(unsigned(cap_reg(5 downto 0)));
bitpos <= to_integer(unsigned(cap_reg(15 downto 8)));
if bitlen > 0 then -- bitlen = 0 disables the capture function
-- bit counter, 0 to 191
if rx_block_start = '1' then
cur_pos <= 0;
cap_len <= 0;
cap_new <= (others => '0');
compared <= '0';
elsif cs_b_en = '1' then -- ch. status #2 comes last, count then
cur_pos <= cur_pos + 1;
end if;
-- capture bits
if cur_pos >= bitpos and cap_len < bitlen then
case d_enable is
when "0001" => -- user data channel A
if cdata = '0' and chid = '0' then
cap_new(cap_len) <= ch_data;
cap_len <= cap_len + 1;
end if;
when "0010" => -- user data channel B
if cdata = '0' and chid = '1' then
cap_new(cap_len) <= ch_data;
cap_len <= cap_len + 1;
end if;
when "0100" => -- channel status ch. A
if cdata = '1' and chid = '0' then
cap_new(cap_len) <= ch_data;
cap_len <= cap_len + 1;
end if;
when "1000" => -- channel status ch. B
if cdata = '1' and chid = '1' then
cap_new(cap_len) <= ch_data;
cap_len <= cap_len + 1;
end if;
when others => null;
end case;
end if;
-- if all bits captured, check with previous data
if cap_len = bitlen and compared = '0' then
compared <= '1';
-- event generated if captured bits differ
if cap_reg_1 /= cap_new then
cap_evt <= '1';
end if;
cap_reg_1 <= cap_new;
else
cap_evt <= '0';
end if;
end if;
end if;
end if;
end process CDAT;
d_enable(0) <= ud_a_en;
d_enable(1) <= ud_b_en;
d_enable(2) <= cs_a_en;
d_enable(3) <= cs_b_en;
end rtl;