Subversion Repositories astron_ram

-------------------------------------------------------------------------------
--
-- 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.
--
-------------------------------------------------------------------------------
 
LIBRARY IEEE, common_pkg_lib, common_components_lib, common_ram_lib, technology_lib, tech_ram_lib;
USE IEEE.std_logic_1164.ALL;
USE common_pkg_lib.common_pkg.ALL;
USE common_ram_lib.common_ram_pkg.ALL;
USE technology_lib.technology_select_pkg.ALL;
 
ENTITY common_ram_crw_crw_ratio IS
  GENERIC (
    g_technology : NATURAL := c_tech_select_default;
    g_ram_a      : t_c_mem := c_mem_ram;  -- settings for port a
    g_ram_b      : t_c_mem := c_mem_ram;  -- data width and address range for port b
    g_init_file  : STRING := "UNUSED"
  );
  PORT (
    rst_a     : IN  STD_LOGIC := '0';
    rst_b     : IN  STD_LOGIC := '0';
    clk_a     : IN  STD_LOGIC;
    clk_b     : IN  STD_LOGIC;
    clken_a   : IN  STD_LOGIC := '1';
    clken_b   : IN  STD_LOGIC := '1';
    wr_en_a   : IN  STD_LOGIC := '0';
    wr_en_b   : IN  STD_LOGIC := '0';
    wr_dat_a  : IN  STD_LOGIC_VECTOR(g_ram_a.dat_w-1 DOWNTO 0) := (OTHERS=>'0');
    wr_dat_b  : IN  STD_LOGIC_VECTOR(g_ram_b.dat_w-1 DOWNTO 0) := (OTHERS=>'0');
    adr_a     : IN  STD_LOGIC_VECTOR(g_ram_a.adr_w-1 DOWNTO 0) := (OTHERS=>'0');
    adr_b     : IN  STD_LOGIC_VECTOR(g_ram_b.adr_w-1 DOWNTO 0) := (OTHERS=>'0');
    rd_en_a   : IN  STD_LOGIC := '1';
    rd_en_b   : IN  STD_LOGIC := '1';
    rd_dat_a  : OUT STD_LOGIC_VECTOR(g_ram_a.dat_w-1 DOWNTO 0);
    rd_dat_b  : OUT STD_LOGIC_VECTOR(g_ram_b.dat_w-1 DOWNTO 0);
    rd_val_a  : OUT STD_LOGIC;
    rd_val_b  : OUT STD_LOGIC
  );
END common_ram_crw_crw_ratio;
 
 
ARCHITECTURE str OF common_ram_crw_crw_ratio IS
 
  CONSTANT c_ram        : t_c_mem := g_ram_a;  -- use shared parameters from port a parameter
 
  CONSTANT c_rd_latency : NATURAL := sel_a_b(c_ram.latency<2,            c_ram.latency,              2);  -- handle read latency 1 or 2 in RAM
  CONSTANT c_pipeline   : NATURAL := sel_a_b(c_ram.latency>c_rd_latency, c_ram.latency-c_rd_latency, 0);  -- handle rest of read latency > 2 in pipeline
 
  -- Intermediate signal for extra pipelining
  SIGNAL ram_rd_dat_a   : STD_LOGIC_VECTOR(rd_dat_a'RANGE);
  SIGNAL ram_rd_dat_b   : STD_LOGIC_VECTOR(rd_dat_b'RANGE);
 
  -- Map sl to single bit slv for rd_val pipelining
  SIGNAL ram_rd_en_a    : STD_LOGIC_VECTOR(0 DOWNTO 0);
  SIGNAL ram_rd_en_b    : STD_LOGIC_VECTOR(0 DOWNTO 0);
  SIGNAL ram_rd_val_a   : STD_LOGIC_VECTOR(0 DOWNTO 0);
  SIGNAL ram_rd_val_b   : STD_LOGIC_VECTOR(0 DOWNTO 0);  
 
BEGIN
 
  ASSERT c_ram.latency >= 1
    REPORT "common_ram_crw_crw_ratio : only support read latency >= 1"
    SEVERITY FAILURE;
 
  ASSERT g_ram_a.latency = g_ram_b.latency
    REPORT "common_ram_crw_crw_ratio : only support same read latency for both ports"
    SEVERITY FAILURE;
 
  -- memory access
  u_ramk : ENTITY tech_ram_lib.tech_memory_ram_crwk_crw
  GENERIC MAP (
    g_technology  => g_technology,
    g_adr_a_w     => g_ram_a.adr_w,
    g_adr_b_w     => g_ram_b.adr_w,
    g_dat_a_w     => g_ram_a.dat_w,
    g_dat_b_w     => g_ram_b.dat_w,
    g_nof_words_a => g_ram_a.nof_dat,
    g_nof_words_b => g_ram_b.nof_dat,
    g_rd_latency  => c_rd_latency,
    g_init_file   => g_init_file
  )
  PORT MAP (
    clock_a     => clk_a,
    clock_b     => clk_b,
    enable_a    => clken_a,
    enable_b    => clken_b,
    wren_a      => wr_en_a,
    wren_b      => wr_en_b,
    data_a      => wr_dat_a,
    data_b      => wr_dat_b,
    address_a   => adr_a,
    address_b   => adr_b,
    q_a         => ram_rd_dat_a,
    q_b         => ram_rd_dat_b
  );
 
  -- read output
  u_pipe_a : ENTITY common_components_lib.common_pipeline
  GENERIC MAP (
    g_pipeline   => c_pipeline,
    g_in_dat_w   => g_ram_a.dat_w,
    g_out_dat_w  => g_ram_a.dat_w
  )
  PORT MAP (
    clk     => clk_a,
    clken   => clken_a,
    in_dat  => ram_rd_dat_a,
    out_dat => rd_dat_a
  );
 
  u_pipe_b : ENTITY common_components_lib.common_pipeline
  GENERIC MAP (
    g_pipeline   => c_pipeline,
    g_in_dat_w   => g_ram_b.dat_w,
    g_out_dat_w  => g_ram_b.dat_w
  )
  PORT MAP (
    clk     => clk_b,
    clken   => clken_b,
    in_dat  => ram_rd_dat_b,
    out_dat => rd_dat_b
  );
 
  -- rd_val control
  ram_rd_en_a(0) <= rd_en_a;
  ram_rd_en_b(0) <= rd_en_b;
 
  rd_val_a <= ram_rd_val_a(0);
  rd_val_b <= ram_rd_val_b(0);
 
  u_rd_val_a : ENTITY common_components_lib.common_pipeline
  GENERIC MAP (
    g_pipeline   => c_ram.latency,
    g_in_dat_w   => 1,
    g_out_dat_w  => 1
  )
  PORT MAP (
    clk     => clk_a,
    clken   => clken_a,
    in_dat  => ram_rd_en_a,
    out_dat => ram_rd_val_a
  );
 
  u_rd_val_b : ENTITY common_components_lib.common_pipeline
  GENERIC MAP (
    g_pipeline   => c_ram.latency,
    g_in_dat_w   => 1,
    g_out_dat_w  => 1
  )
  PORT MAP (
    clk     => clk_b,
    clken   => clken_b,
    in_dat  => ram_rd_en_b,
    out_dat => ram_rd_val_b
  );
 
END str;