Subversion Repositories astron_wb_fft

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--

-- 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.

--

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-- Purpose: Wideband FFT with Subband Statistics and streaming interfaces. 

--

-- Description: This unit connects an incoming array of streaming interfaces

--              to the wideband fft. The output of the wideband fft is 

--              connected to a set of subband statistics units. The statistics

--              can be read via the memory mapped interface. 

--              A control unit takes care of the correct composition of the

--              output streams(sop,eop,sync,bsn,err).

--

-- Remarks:   . The unit can handle only one sync at a time. Therfor the 

--              sync interval should be larger than the total pipeline

--              stages of the wideband fft. 

library ieee, common_pkg_lib, astron_ram_lib, dp_pkg_lib, astron_r2sdf_fft_lib, astron_statistics_lib, astron_mm_lib, astron_requantize_lib;

use IEEE.std_logic_1164.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 astron_r2sdf_fft_lib.rTwoSDFPkg.all;

use astron_statistics_lib.all;

use work.fft_pkg.all;

entity fft_wide_unit is

  generic (

    g_fft          : t_fft := c_fft;                   -- generics for the FFT

    g_pft_pipeline : t_fft_pipeline := c_fft_pipeline; -- For the pipelined part, defined in astron_r2sdf_fft_lib.rTwoSDFPkg

    g_fft_pipeline : t_fft_pipeline := c_fft_pipeline  -- For the parallel part, defined in astron_r2sdf_fft_lib.rTwoSDFPkg

  );

  port (

    dp_rst          : in  std_logic := '0';

    dp_clk          : in  std_logic;

    mm_rst          : in  std_logic;

    mm_clk          : in  std_logic;

    ram_st_sst_mosi : in  t_mem_mosi;                   -- Subband statistics registers

    ram_st_sst_miso : out t_mem_miso := c_mem_miso_rst;

    in_sosi_arr     : in  t_dp_sosi_arr(g_fft.wb_factor-1 downto 0);

    out_sosi_arr    : out t_dp_sosi_arr(g_fft.wb_factor-1 downto 0)

  );

end entity fft_wide_unit;

architecture str of fft_wide_unit is

  constant c_lsb_w_tester    : integer := g_fft.out_dat_w - g_fft.stage_dat_w;

  constant c_lsb_w           : natural := sel_a_b(c_lsb_w_tester > 0, c_lsb_w_tester, 0);

  constant c_nof_stats       : natural := (2**g_fft.nof_chan)*g_fft.nof_points/g_fft.wb_factor;

  signal ram_st_sst_mosi_arr : t_mem_mosi_arr(g_fft.wb_factor-1 downto 0);

  signal ram_st_sst_miso_arr : t_mem_miso_arr(g_fft.wb_factor-1 downto 0);

  signal fft_in_re_arr       : t_fft_slv_arr(g_fft.wb_factor-1 downto 0);

  signal fft_in_im_arr       : t_fft_slv_arr(g_fft.wb_factor-1 downto 0);

  signal fft_out_re_arr      : t_fft_slv_arr(g_fft.wb_factor-1 downto 0);

  signal fft_out_im_arr      : t_fft_slv_arr(g_fft.wb_factor-1 downto 0);

  signal fft_out_val         : std_logic;

  signal fft_out_sosi_arr    : t_dp_sosi_arr(g_fft.wb_factor-1 downto 0);

  signal sst_in_sosi_arr     : t_dp_sosi_arr(g_fft.wb_factor-1 downto 0);

  type reg_type is record

    in_sosi_arr : t_dp_sosi_arr(g_fft.wb_factor-1 downto 0);

  end record;

  signal r, rin : reg_type;

begin

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

  -- INPUT REGISTER FOR THE SOSI ARRAY

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

  -- The complete input sosi arry is registered. 

  comb : process(r, in_sosi_arr)

    variable v : reg_type;

  begin

    v             := r;

    v.in_sosi_arr := in_sosi_arr;

    rin           <= v;

  end process comb;

  regs : process(dp_clk)

  begin

    if rising_edge(dp_clk) then

      r <= rin;

    end if;

  end process;

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

  -- COMBINE MEMORY MAPPED INTERFACES

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

  -- Combine the internal array of mm interfaces for the subband 

  -- statistics to one array that is connected to the port of the 

  -- fft_wide_unit.

  u_mem_mux_sst : entity astron_mm_lib.common_mem_mux

  generic map (

    g_nof_mosi    => g_fft.wb_factor,

    g_mult_addr_w => ceil_log2(g_fft.stat_data_sz*c_nof_stats)

  )

  port map (

    mosi     => ram_st_sst_mosi,

    miso     => ram_st_sst_miso,

    mosi_arr => ram_st_sst_mosi_arr,

    miso_arr => ram_st_sst_miso_arr

  );

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

  -- PREPARE INPUT DATA FOR WIDEBAND FFT

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

  -- Extract the data from the in_sosi_arr records and resize it 

  -- to fit the format of the fft_r2_wide unit. 

  gen_prep_fft_data: for I in 0 to g_fft.wb_factor-1 generate

    fft_in_re_arr(I) <= RESIZE_SVEC(r.in_sosi_arr(I).re(g_fft.in_dat_w-1 downto 0), fft_in_re_arr(I)'length);

    fft_in_im_arr(I) <= RESIZE_SVEC(r.in_sosi_arr(I).im(g_fft.in_dat_w-1 downto 0), fft_in_im_arr(I)'length);

  end generate;

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

  -- THE WIDEBAND FFT

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

  u_fft_wide : entity work.fft_r2_wide

  generic map(

    g_fft          => g_fft,         -- generics for the WFFT

    g_pft_pipeline => g_pft_pipeline,

    g_fft_pipeline => g_fft_pipeline

  )

  port map(

    clk        => dp_clk,

    rst        => dp_rst,

    in_re_arr  => fft_in_re_arr,

    in_im_arr  => fft_in_im_arr,

    in_val     => r.in_sosi_arr(0).valid,

    out_re_arr => fft_out_re_arr,

    out_im_arr => fft_out_im_arr,

    out_val    => fft_out_val

  );

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

  -- FFT CONTROL UNIT

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

  -- The fft control unit composes the output array in the dp-

  -- streaming format. 

  u_fft_control : entity work.fft_wide_unit_control

  generic map (

    g_fft         => g_fft

  )

  port map(

    rst          => dp_rst,

    clk          => dp_clk,

    in_re_arr    => fft_out_re_arr,

    in_im_arr    => fft_out_im_arr,

    in_val       => fft_out_val,

    ctrl_sosi    => r.in_sosi_arr(0),

    out_sosi_arr => fft_out_sosi_arr

  );

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

  -- SUBBAND STATISTICS 

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

  -- For all "wb_factor" output streams of the wideband FFT a 

  -- subband statistics unit is placed. 

  -- Since the subband statistics module uses embedded DSP blocks

  -- for multiplication, the incoming data cannot be wider 

  -- than 18 bit. Therefor a quantizer is inserted.  

  gen_subband_stats: for I in 0 to g_fft.wb_factor-1 generate

    u_quantizer_for_bst : entity astron_requantize_lib.dp_requantize

    GENERIC MAP (

      g_complex             => TRUE,

      g_representation      => "SIGNED",

      g_lsb_w               => c_lsb_w,

      g_lsb_round           => TRUE,

      g_lsb_round_clip      => FALSE,

      g_msb_clip            => TRUE,

      g_msb_clip_symmetric  => TRUE,

      g_pipeline_remove_lsb => 1,

      g_pipeline_remove_msb => 1,

      g_in_dat_w            => g_fft.out_dat_w,

      g_out_dat_w           => g_fft.stage_dat_w

    )

    PORT MAP (

      rst        => dp_rst,

      clk        => dp_clk,

      snk_in     => fft_out_sosi_arr(I),

      src_out    => sst_in_sosi_arr(I),

      out_ovr    => OPEN

    );

    u_subband_stats : entity astron_statistics_lib.st_sst

    generic map(

      g_nof_stat      => c_nof_stats,

      g_in_data_w     => g_fft.stage_dat_w,

      g_stat_data_w   => g_fft.stat_data_w,

      g_stat_data_sz  => g_fft.stat_data_sz

    )

    port map (

      mm_rst          => mm_rst,

      mm_clk          => mm_clk,

      dp_rst          => dp_rst,

      dp_clk          => dp_clk,

      in_complex      => sst_in_sosi_arr(I),

      ram_st_sst_mosi => ram_st_sst_mosi_arr(I),

      ram_st_sst_miso => ram_st_sst_miso_arr(I)

    );

  end generate;

  -- Connect to the outside world 

  gen_output : for I in 0 to g_fft.wb_factor-1 generate

    out_sosi_arr(I) <= fft_out_sosi_arr(I);

  end generate;

end str;