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-------------------------------------------------------------------------------
-- Title : Parametrizable dual-port synchronous RAM (Altera version)
-- Project : Generics RAMs and FIFOs collection
-------------------------------------------------------------------------------
-- File : generic_dpram.vhd
-- Author : C. Prados
-- Company : GSI
-- Created : 2014-08-25
-- Last update:
-- Platform :
-- Standard : VHDL'93
-------------------------------------------------------------------------------
-- Description: True dual-port synchronous RAM for Altera FPGAs with:
-- - configurable address and data bus width
-- - byte-addressing mode (data bus width restricted to multiple of 8 bits)
-------------------------------------------------------------------------------
-- Copyright (c) 2013 GSI
-------------------------------------------------------------------------------
-- Revisions :
-- Date Version Author Description
-- 2014-08-25 1.0 Prados Created
-------------------------------------------------------------------------------
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
library work;
use work.genram_pkg.all;
library altera_mf;
use altera_mf.altera_mf_components.all;
entity generic_dpram_mixed is
generic(
-- standard parameters
g_data_a_width : natural;
g_data_b_width : natural;
g_size : natural;
g_addr_conflict_resolution : string := "dont_care";
g_init_file : string := "none";
g_dual_clock : boolean := true);
port(
rst_n_i : in std_logic := '1'; -- synchronous reset, active LO
-- Port A
clka_i : in std_logic;
bwea_i : in std_logic_vector((g_data_a_width+7)/8-1 downto 0);
wea_i : in std_logic;
aa_i : in std_logic_vector(f_log2_size(g_size)-1 downto 0);
da_i : in std_logic_vector(g_data_a_width-1 downto 0);
qa_o : out std_logic_vector(g_data_a_width-1 downto 0);
-- Port B
clkb_i : in std_logic;
bweb_i : in std_logic_vector((g_data_b_width+7)/8-1 downto 0);
web_i : in std_logic;
ab_i : in std_logic_vector(f_log2_size(g_data_a_width*g_size/g_data_b_width)-1 downto 0);
db_i : in std_logic_vector(g_data_b_width-1 downto 0);
qb_o : out std_logic_vector(g_data_b_width-1 downto 0)
);
end generic_dpram_mixed;
architecture syn of generic_dpram_mixed is
function f_sameport_order(x : string) return string is
begin
if x = "read_first" then
return "OLD_DATA";
elsif x = "write_first" then
--return "NEW_DATA_NO_NBE_READ"; -- unwritten bytes='X'
return "NEW_DATA_WITH_NBE_READ"; -- unwritten bytes=OLD_DATA (ie: whole result = NEW_DATA)
elsif x = "dont_care" then
return "DONT_CARE";
else
assert (false) report "generic_dpram: g_addr_conflict_resolution must be: read_first, write_first, dont_care" severity failure;
return "DONT_CARE";
end if;
end f_sameport_order;
function f_filename(x : string) return string is
begin
if x'length = 0 or x = "none" then
return "UNUSED";
else
return x;
end if;
end f_filename;
constant c_num_a_bytes : integer := (g_data_a_width+7)/8;
constant c_num_b_bytes : integer := (g_data_b_width+7)/8;
constant c_addr_a_width : integer := f_log2_size(g_size);
constant c_addr_b_width : integer := f_log2_size(g_data_a_width*g_size/g_data_b_width);
constant sameport_order : string := f_sameport_order(g_addr_conflict_resolution);
constant c_init_file : string := f_filename(g_init_file);
signal qa : std_logic_vector(g_data_a_width-1 downto 0);
signal qb : std_logic_vector(g_data_b_width-1 downto 0);
signal da : std_logic_vector(g_data_a_width-1 downto 0);
signal db : std_logic_vector(g_data_b_width-1 downto 0);
signal nba : boolean;
signal nbb : boolean;
begin
assert (g_addr_conflict_resolution /= "read_first" or g_dual_clock = false)
report "generic_dpram: read_first is only possible when dual_clock is false"
severity failure;
assert (g_addr_conflict_resolution /= "write_first")
report "generic_dpram: write_first requires a bypass MUX"
severity note;
case_qb_raw : if (g_addr_conflict_resolution /= "write_first") generate
qa_o <= qa;
qb_o <= qb;
end generate;
case_qb_bypass : if (g_addr_conflict_resolution = "write_first") generate
qa_o <= qa when nba else db;
qb_o <= qb when nbb else da;
memoize : process(clka_i) is
begin
if rising_edge(clka_i) then
nba <= aa_i /= ab_i or web_i = '0';
nbb <= aa_i /= ab_i or wea_i = '0';
da <= da_i;
db <= db_i;
end if;
end process;
end generate;
ram : altsyncram
generic map (
byte_size => 8,
address_reg_b => "clock1",
byteena_reg_b => "clock1",
indata_reg_b => "clock1",
wrcontrol_wraddress_reg_b => "clock1",
clock_enable_input_a => "bypass",
clock_enable_input_b => "bypass",
clock_enable_output_a => "bypass",
clock_enable_output_b => "bypass",
init_file => c_init_file,
init_file_layout => "port_a",
lpm_type => "altsyncram",
operation_mode => "bidir_dual_port",
outdata_aclr_a => "none",
outdata_aclr_b => "none",
outdata_reg_a => "unregistered",
outdata_reg_b => "unregistered",
power_up_uninitialized => "false",
read_during_write_mode_port_a => sameport_order,
read_during_write_mode_port_b => sameport_order,
numwords_a => g_size,
numwords_b => g_size*g_data_a_width/g_data_b_width,
widthad_a => f_log2_size(g_size),
widthad_b => f_log2_size(g_data_a_width*g_size/g_data_b_width),
width_a => g_data_a_width,
width_b => g_data_b_width,
width_byteena_a => (g_data_a_width+7)/8,
width_byteena_b => (g_data_b_width+7)/8
)
port map (
clock0 => clka_i,
address_a => aa_i,
data_a => da_i,
q_a => qa,
byteena_a => bwea_i,
wren_a => wea_i,
clock1 => clkb_i,
address_b => ab_i,
data_b => db_i,
q_b => qb,
byteena_b => bweb_i,
wren_b => web_i);
end syn;