Subversion Repositories astron_wb_fft

-------------------------------------------------------------------------------

--

-- Copyright 2020

-- ASTRON (Netherlands Institute for Radio Astronomy) <http://www.astron.nl/>

-- P.O.Box 2, 7990 AA Dwingeloo, The Netherlands

-- 

-- Licensed under the Apache License, Version 2.0 (the "License");

-- you may not use this file except in compliance with the License.

-- You may obtain a copy of the License at

-- 

--     http://www.apache.org/licenses/LICENSE-2.0

-- 

-- Unless required by applicable law or agreed to in writing, software

-- distributed under the License is distributed on an "AS IS" BASIS,

-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

-- See the License for the specific language governing permissions and

-- limitations under the License.

--

-------------------------------------------------------------------------------

-- Purpose: Composition of the SOSI output streams for the fft_wide_unit. 

--

-- Description: This unit monitors the in_val signal. Based on the assertion of the 

--              in_val signal it will compose the output sosi streams. The packet-

--              size equals g_fft.nof_points/g_fft.wb_factor. 

--              Both the incoming bsn and err fields are written to a fifo. When 

--              the output is composed the bsn and err field will be read from the 

--              fifo's. 

--              Incoming syncs will be detected and the bsn that accompanies the sync

--              will be stored. When the bsn that is read from the fifo is the same 

--              as the stored one, the sync will be asserted to the output. 

--

-- Remarks:    .The sync interval must be larger that the total amount of pipeline

--              stages in the FFT. In other words: the fft_wide_unit_control unit 

--              is not capable of handling more than one sync pulse at a time. 

--              

--

library IEEE, common_pkg_lib, astron_ram_lib, astron_fifo_lib, dp_pkg_lib;

use IEEE.std_logic_1164.ALL;

use IEEE.numeric_std.ALL;

use common_pkg_lib.common_pkg.ALL;

use astron_ram_lib.common_ram_pkg.ALL;

use dp_pkg_lib.dp_stream_pkg.ALL;

use work.fft_pkg.ALL;

entity fft_wide_unit_control is

  generic (

    g_fft      : t_fft   := c_fft;

    g_nof_ffts : natural := 1

  );

  port (

    rst          : in  std_logic := '0';

    clk          : in  std_logic;

    in_re_arr    : in  t_fft_slv_arr(g_nof_ffts*g_fft.wb_factor-1 downto 0);

    in_im_arr    : in  t_fft_slv_arr(g_nof_ffts*g_fft.wb_factor-1 downto 0);

    in_val       : in  std_logic;

    ctrl_sosi    : in  t_dp_sosi;                                            -- Inputrecord for tapping off the sync, bsn and err.              

    out_sosi_arr : out t_dp_sosi_arr(g_nof_ffts*g_fft.wb_factor-1 downto 0)  -- Streaming output interface    

  );

end fft_wide_unit_control;

architecture rtl of fft_wide_unit_control is

  constant c_pipe_data       : natural := 3;                                -- Delay depth for the data 

  constant c_pipe_ctrl       : natural := c_pipe_data-1;                    -- Delay depth for the control signals

  constant c_packet_size     : natural := (2**g_fft.nof_chan)*g_fft.nof_points/g_fft.wb_factor; -- Definition of the packet size

  constant c_ctrl_fifo_depth : natural := 16;                               -- Depth of the bsn and err fifo.  

  type t_fft_slv_arr2 is array (integer range <>) of t_fft_slv_arr(g_nof_ffts*g_fft.wb_factor-1 downto 0);

  type state_type     is (s_idle, s_run, s_hold);

  type reg_type is record

    out_sosi_arr   : t_dp_sosi_arr(g_nof_ffts*g_fft.wb_factor-1 downto 0); -- Register that holds the streaming interface          

    in_re_arr2_dly : t_fft_slv_arr2(c_pipe_data              -1 downto 0); -- Input registers for the real data 

    in_im_arr2_dly : t_fft_slv_arr2(c_pipe_data              -1 downto 0); -- Input registers for the imag data  

    val_dly        : std_logic_vector(c_pipe_ctrl            -1 downto 0); -- Delay-register for the valid signal

    sop_dly        : std_logic_vector(c_pipe_ctrl            -1 downto 0); -- Delay-register for the sop signal

    eop_dly        : std_logic_vector(c_pipe_ctrl            -1 downto 0); -- Delay-register for the eop signal

    sync_detected  : std_logic;                                            -- Register used to detect and pass the sync pulse.

    packet_cnt     : integer;                                              -- Counter to create the packets. 

    state          : state_type;                                           -- The state machine. 

  end record;

  signal r, rin   : reg_type;

  signal bsn      : std_logic_vector(c_dp_stream_bsn_w  -1 downto 0);

  signal sync_bsn : std_logic_vector(c_dp_stream_bsn_w  -1 downto 0);

  signal err      : std_logic_vector(c_dp_stream_error_w-1 downto 0);

  signal rd_req   : std_logic;

  signal rd_req_i : std_logic;

  signal rd_dat_i : std_logic_vector(c_dp_stream_bsn_w  -1 downto 0);

  signal rd_val_i : std_logic;

begin

  ---------------------------------------------------------------

  -- INPUT FIFO FOR BSN

  ---------------------------------------------------------------

  u_bsn_fifo : entity astron_fifo_lib.common_fifo_sc

  generic map (

    g_use_lut   => TRUE,   -- Make this FIFO in logic, since it's only 4 words deep. 

    g_reset     => FALSE,

    g_init      => FALSE,

    g_dat_w     => c_dp_stream_bsn_w,

    g_nof_words => c_ctrl_fifo_depth

  )

  port map (

    rst     => rst,

    clk     => clk,

    wr_dat  => ctrl_sosi.bsn,

    wr_req  => ctrl_sosi.sop,

    wr_ful  => open ,

    rd_dat  => bsn,

    rd_req  => r.sop_dly(0),

    rd_emp  => open ,

    rd_val  => open ,

    usedw   => open

  );

  ---------------------------------------------------------------

  -- INPUT FIFO FOR ERR

  ---------------------------------------------------------------

  u_error_fifo : entity astron_fifo_lib.common_fifo_sc

  generic map (

    g_use_lut   => TRUE,   -- Make this FIFO in logic, since it's only 4 words deep. 

    g_reset     => FALSE,

    g_init      => FALSE,

    g_dat_w     => c_dp_stream_error_w,

    g_nof_words => c_ctrl_fifo_depth

  )

  port map (

    rst     => rst,

    clk     => clk,

    wr_dat  => ctrl_sosi.err,

    wr_req  => ctrl_sosi.sop,

    wr_ful  => open ,

    rd_dat  => err,

    rd_req  => r.sop_dly(1),

    rd_emp  => open ,

    rd_val  => open ,

    usedw   => open

  );

  ---------------------------------------------------------------

  -- FIFO FOR SYNC-BSN

  ---------------------------------------------------------------

  u_sync_bsn_fifo : entity astron_fifo_lib.common_fifo_sc

  generic map (

    g_use_lut   => TRUE,   -- Make this FIFO in logic, since it's only 4 words deep. 

    g_reset     => FALSE,

    g_init      => FALSE,

    g_dat_w     => c_dp_stream_bsn_w,

    g_nof_words => 2

  )

  port map (

    rst     => rst,

    clk     => clk,

    wr_dat  => ctrl_sosi.bsn,

    wr_req  => ctrl_sosi.sync,

    wr_ful  => open ,

    rd_dat  => rd_dat_i,

    rd_req  => rd_req_i,

    rd_emp  => open,

    rd_val  => rd_val_i,

    usedw   => open

  );

  ---------------------------------------------------------------

  -- CREATE READ-AHEAD FIFO INTERFACE FOR SYNC-BSN

  ---------------------------------------------------------------

  u_fifo_adapter : entity astron_fifo_lib.common_fifo_rd

  generic map (

    g_dat_w => c_dp_stream_bsn_w

  )

  port map(

    rst        => rst,

    clk        => clk,

    -- ST sink: RL = 1

    fifo_req   => rd_req_i,

    fifo_dat   => rd_dat_i,

    fifo_val   => rd_val_i,

    -- ST source: RL = 0

    rd_req     => rd_req,

    rd_dat     => sync_bsn,

    rd_val     => open

  );

  rd_req <= r.out_sosi_arr(0).sync; --  (r.sync_detected and not(rd_emp)) or r.rd_first; 

  ---------------------------------------------------------------

  -- PROCESS THAT COMPOSES THE SOSI OUTPUT ARRAYS

  ---------------------------------------------------------------

  comb : process(r, rst, ctrl_sosi, in_re_arr, in_im_arr, in_val, sync_bsn, bsn, err)

    variable v : reg_type;

  begin

    v := r;

    v.val_dly(0)  := '0';              -- Some defaults, before entering the state machine.              

    v.sop_dly(0)  := '0';

    v.eop_dly(0)  := '0';

    for I in g_nof_ffts*g_fft.wb_factor-1 downto 0 loop

      v.out_sosi_arr(I).sync  := '0';

    end loop;

    v.in_re_arr2_dly(0) := in_re_arr;  -- Latch the data into the input registers. 

    v.in_im_arr2_dly(0) := in_im_arr;  -- Latch the data into the input registers. 

    v.in_re_arr2_dly(c_pipe_data-1 downto 1) := r.in_re_arr2_dly(c_pipe_data-2 downto 0); -- Shift the delay registers

    v.in_im_arr2_dly(c_pipe_data-1 downto 1) := r.in_im_arr2_dly(c_pipe_data-2 downto 0); -- Shift the delay registers

    v.val_dly(c_pipe_ctrl-1 downto 1)        := r.val_dly(c_pipe_ctrl-2 downto 0);        -- Shift the delay registers

    v.sop_dly(c_pipe_ctrl-1 downto 1)        := r.sop_dly(c_pipe_ctrl-2 downto 0);        -- Shift the delay registers

    v.eop_dly(c_pipe_ctrl-1 downto 1)        := r.eop_dly(c_pipe_ctrl-2 downto 0);        -- Shift the delay registers

    for I in g_nof_ffts*g_fft.wb_factor-1 downto 0 loop

      v.out_sosi_arr(I).sop   := r.sop_dly(c_pipe_ctrl-1);  -- Assign the output of the shiftregisters to the "real" signals

      v.out_sosi_arr(I).eop   := r.eop_dly(c_pipe_ctrl-1);  -- Assign the output of the shiftregisters to the "real" signals

      v.out_sosi_arr(I).valid := r.val_dly(c_pipe_ctrl-1);  -- Assign the output of the shiftregisters to the "real" signals

      v.out_sosi_arr(I).bsn   := bsn;                       -- The bsn is read from the FIFO

      v.out_sosi_arr(I).err   := err;                       -- The err is read from the FIFO

      v.out_sosi_arr(I).re    := RESIZE_SVEC(r.in_re_arr2_dly(c_pipe_data-1)(I), c_dp_stream_dsp_data_w); -- Data input is latched-in 

      v.out_sosi_arr(I).im    := RESIZE_SVEC(r.in_im_arr2_dly(c_pipe_data-1)(I), c_dp_stream_dsp_data_w); -- Data input is latched-in 

    end loop;

    if(ctrl_sosi.sync = '1') then                           -- Check which bsn accompanies the sync

      v.sync_detected := '1';

    end if;

    if(sync_bsn = bsn and r.sop_dly(1) = '1' and r.sync_detected = '1') then -- When the next bsn equals the stored bsn 

      for I in g_fft.wb_factor-1 downto 0 loop                                 -- a sync pulse will be generated that 

        v.out_sosi_arr(I).sync  := '1';                                        -- preceeds the sop

      end loop;

      v.sync_detected := '0';

    end if;

    case r.state is

            when s_idle =>

                if(in_val = '1') then                       -- Wait for the first data to arrive

                  v.packet_cnt := 0;                        -- Reset the packet counter

                        v.state      := s_run;

                end if;

            when s_run =>

              v.val_dly(0) := '1';                        -- Assert the valid signal (Stream starts)

              v.packet_cnt := r.packet_cnt + 1;           -- Increment the packet-counter when in s_run-state

        if(r.packet_cnt = 0) then                   -- First sample marks

          v.sop_dly(0) :='1';                       -- the start of a packet

        elsif(r.packet_cnt = c_packet_size-1) then  -- Last address marks  

          v.eop_dly(0) :='1';                       -- the end of a packet

          v.packet_cnt := 0;                        -- Reset the counter

        end if;

        if(in_val = '0') then                       -- If there is no more data:

          v.state := s_hold;                        -- go wait in the s_hold state

        end if;

      when s_hold =>

        if(in_val = '1') then                       -- Wait until new valid data arrives

          v.state := s_run;

        end if;

            when others =>

              v.state := s_idle;

          end case;

    if(rst = '1') then

      v.out_sosi_arr  := (others => c_dp_sosi_rst);

      v.val_dly       := (others => '0');

      v.sop_dly       := (others => '0');

      v.eop_dly       := (others => '0');

      v.sync_detected := '0';

      v.packet_cnt    := 0;

      v.state         := s_idle;

    end if;

    rin <= v;

  end process comb;

  regs : process(clk)

  begin

    if rising_edge(clk) then

      r <= rin;

    end if;

  end process;

  -- Connect to the outside world  

  gen_output : for I in g_nof_ffts*g_fft.wb_factor-1 downto 0 generate

    out_sosi_arr(I) <= r.out_sosi_arr(I);

  end generate;

end rtl;