pluto_hdl_adi/library/axi_i2s_adi/i2s_rx.vhd

181 lines
5.9 KiB
VHDL

-- ***************************************************************************
-- ***************************************************************************
-- Copyright 2013(c) Analog Devices, Inc.
-- Author: Lars-Peter Clausen <lars-peter.clausen@analog.com>
--
-- All rights reserved.
--
-- Redistribution and use in source and binary forms, with or without modification,
-- are permitted provided that the following conditions are met:
-- - Redistributions of source code must retain the above copyright
-- notice, this list of conditions and the following disclaimer.
-- - Redistributions in binary form must reproduce the above copyright
-- notice, this list of conditions and the following disclaimer in
-- the documentation and/or other materials provided with the
-- distribution.
-- - Neither the name of Analog Devices, Inc. nor the names of its
-- contributors may be used to endorse or promote products derived
-- from this software without specific prior written permission.
-- - The use of this software may or may not infringe the patent rights
-- of one or more patent holders. This license does not release you
-- from the requirement that you obtain separate licenses from these
-- patent holders to use this software.
-- - Use of the software either in source or binary form, must be run
-- on or directly connected to an Analog Devices Inc. component.
--
-- THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
-- INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A
-- PARTICULAR PURPOSE ARE DISCLAIMED.
--
-- IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
-- EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, INTELLECTUAL PROPERTY
-- RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
-- BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
-- STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
-- THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-- ***************************************************************************
-- ***************************************************************************
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity i2s_rx is
generic(
C_SLOT_WIDTH : integer := 24; -- Width of one Slot
C_NUM : integer := 1
);
port(
clk : in std_logic; -- System clock
resetn : in std_logic; -- System reset
enable : in Boolean; -- Enable RX
bclk : in std_logic; -- Bit Clock
channel_sync : in std_logic; -- Channel Sync
frame_sync : in std_logic; -- Frame Sync
sdata : in std_logic_vector(C_NUM - 1 downto 0); -- Serial Data Output
stb : out std_logic; -- Data available
ack : in std_logic; -- Data has been consumed
data : out std_logic_vector(C_SLOT_WIDTH-1 downto 0) -- Slot Data in
);
end i2s_rx;
architecture Behavioral of i2s_rx is
type mem is array (0 to C_NUM - 1) of std_logic_vector(31 downto 0);
type mem_latched is array (0 to C_NUM - 1) of std_logic_vector(C_SLOT_WIDTH - 1 downto 0);
signal data_int : mem;
signal data_latched : mem_latched;
signal reset_int : Boolean;
signal enable_int : Boolean;
signal bit_sync : std_logic;
signal channel_sync_int : std_logic;
signal frame_sync_int : std_logic;
signal bclk_d1 : std_logic;
type sequencer_state_type is (IDLE, ACTIVE);
signal sequencer_state : sequencer_state_type;
signal seq : natural range 0 to C_NUM - 1;
signal ovf_frame_cnt : natural range 0 to 1;
begin
reset_int <= (resetn = '0') or not enable;
process (clk)
begin
if rising_edge(clk) then
if resetn = '0' then
bclk_d1 <= '0';
else
bclk_d1 <= bclk;
end if;
end if;
end process;
bit_sync <= (bclk xor bclk_d1) and bclk;
channel_sync_int <= channel_sync and bit_sync;
frame_sync_int <= frame_sync and bit_sync;
stb <= '1' when sequencer_state = ACTIVE else '0';
sequencer: process (clk)
begin
if rising_edge(clk) then
if reset_int or not enable_int then
sequencer_state <= IDLE;
ovf_frame_cnt <= 0;
seq <= 0;
else
case sequencer_state is
when IDLE =>
if channel_sync_int = '1' then
if ovf_frame_cnt = 0 then
sequencer_state <= ACTIVE;
else
ovf_frame_cnt <= (ovf_frame_cnt + 1) mod 2;
end if;
end if;
when ACTIVE =>
-- The unlikely event the last ack came in in the same clock
-- cyclce as the channel sync signal will still be treated
-- as an overflow. This keeps the logic simple
if ack = '1' then
if seq = C_NUM - 1 then
sequencer_state <= IDLE;
seq <= 0;
else
seq <= seq + 1;
end if;
end if;
if channel_sync_int = '1' then
ovf_frame_cnt <= (ovf_frame_cnt + 1) mod 2;
end if;
end case;
end if;
end if;
end process;
data <= data_latched(seq);
gen: for i in 0 to C_NUM - 1 generate
unserialize_data: process(clk)
begin
if rising_edge(clk) then
if reset_int then
data_int(i) <= (others => '0');
elsif bit_sync = '1' then
if channel_sync = '1' then
if sequencer_state = IDLE then
data_latched(i) <= data_int(i)(31 downto 32 - C_SLOT_WIDTH);
-- data_latched(i) <= data_int(i)(31 downto 32 -
-- C_SLOT_WIDTH + 8) &
-- std_logic_vector(to_unsigned(i+1,8));
end if;
end if;
data_int(i) <= data_int(i)(30 downto 0) & sdata(i);
end if;
end if;
end process unserialize_data;
end generate;
enable_sync: process (clk)
begin
if rising_edge(clk) then
if reset_int then
enable_int <= False;
else
if enable and frame_sync_int = '1' then
enable_int <= True;
elsif not enable then
enable_int <= False;
end if;
end if;
end if;
end process enable_sync;
end Behavioral;