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Wesley W. Terpstra authored4f84b3e6
generic_simple_dpram.vhd 9.64 KiB
-------------------------------------------------------------------------------
-- Title : Parametrizable dual-port synchronous RAM (Altera version)
-- Project : Generics RAMs and FIFOs collection
-------------------------------------------------------------------------------
-- File : generic_simple_dpram.vhd
-- Author : Wesley W. Terpstra
-- Company : GSI
-- Created : 2013-03-04
-- Last update: 2013-03-04
-- Platform :
-- Standard : VHDL'93
-------------------------------------------------------------------------------
-- Description: Simple 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
-- 2013-03-04 1.0 wterpstra Adapted from generic_dpram.vhd
-------------------------------------------------------------------------------
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_simple_dpram is
generic(
g_data_width : natural;
g_size : natural;
g_with_byte_enable : boolean := false;
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_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_width-1 downto 0);
-- Port B
clkb_i : in std_logic;
ab_i : in std_logic_vector(f_log2_size(g_size)-1 downto 0);
qb_o : out std_logic_vector(g_data_width-1 downto 0)
);
end generic_simple_dpram;
architecture syn of generic_simple_dpram is
function f_diffport_order(x : string) return string is
begin
if x = "read_first" then
return "OLD_DATA";
elsif x = "write_first" then
return "DONT_CARE"; -- "NEW_DATA" is unsupported; we use a bypass MUX in this case
elsif x = "dont_care" then
return "DONT_CARE";
else assert (false) report "generic_simple_dpram: g_addr_conflict_resolution must be: read_first, write_first, dont_care" severity failure;
return "DONT_CARE";
end if;
end f_diffport_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_bytes : integer := (g_data_width+7)/8;
constant c_addr_width : integer := f_log2_size(g_size);
constant diffport_order : string := f_diffport_order(g_addr_conflict_resolution);
constant c_init_file : string := f_filename(g_init_file);
signal qb : std_logic_vector(g_data_width-1 downto 0);
signal da : std_logic_vector(g_data_width-1 downto 0);
signal nbb : boolean;
begin
assert (g_addr_conflict_resolution /= "write_first" or (g_dual_clock = false and g_with_byte_enable = false))
report "generic_simple_dpram: write_first is only possible when dual_clock and g_with_byte_enable are false"
severity failure;
assert (g_addr_conflict_resolution /= "read_first" or g_dual_clock = false)
report "generic_simple_dpram: read_first is only possible when dual_clock is false"
severity failure;
assert (g_addr_conflict_resolution /= "write_first")
report "generic_simple_dpram: write_first requires a bypass MUX"
severity note;
case_qb_raw : if (g_addr_conflict_resolution /= "write_first") generate
qb_o <= qb;
end generate;
case_qb_bypass : if (g_addr_conflict_resolution = "write_first") generate
qb_o <= qb when nbb else da;
memoize : process(clka_i) is
begin
if rising_edge(clka_i) then
nbb <= aa_i /= ab_i or wea_i = '0';
da <= da_i;
end if;
end process;
end generate;
case_be_dual : if (g_with_byte_enable = true and g_dual_clock = true) generate
memory : altsyncram
generic map(
byte_size => 8,
numwords_a => g_size,
numwords_b => g_size,
widthad_a => c_addr_width,
widthad_b => c_addr_width,
width_a => g_data_width,
width_b => g_data_width,
width_byteena_a => c_num_bytes,
operation_mode => "DUAL_PORT",
read_during_write_mode_mixed_ports => diffport_order,
outdata_reg_a => "UNREGISTERED",
outdata_reg_b => "UNREGISTERED",
address_reg_b => "CLOCK1",
wrcontrol_wraddress_reg_b => "CLOCK1", byteena_reg_b => "CLOCK1",
indata_reg_b => "CLOCK1",
rdcontrol_reg_b => "CLOCK1",
init_file => c_init_file)
port map(
clock0 => clka_i,
wren_a => wea_i,
address_a => aa_i,
data_a => da_i,
byteena_a => bwea_i,
clock1 => clkb_i,
address_b => ab_i,
q_b => qb);
end generate;
case_be_single : if (g_with_byte_enable = true and g_dual_clock = false) generate
memory : altsyncram
generic map(
byte_size => 8,
numwords_a => g_size,
numwords_b => g_size,
widthad_a => c_addr_width,
widthad_b => c_addr_width,
width_a => g_data_width,
width_b => g_data_width,
width_byteena_a => c_num_bytes,
operation_mode => "DUAL_PORT",
read_during_write_mode_mixed_ports => diffport_order,
outdata_reg_a => "UNREGISTERED",
outdata_reg_b => "UNREGISTERED",
address_reg_b => "CLOCK0",
wrcontrol_wraddress_reg_b => "CLOCK0",
byteena_reg_b => "CLOCK0",
indata_reg_b => "CLOCK0",
rdcontrol_reg_b => "CLOCK0",
init_file => c_init_file)
port map(
clock0 => clka_i,
wren_a => wea_i,
address_a => aa_i,
data_a => da_i,
byteena_a => bwea_i,
address_b => ab_i,
q_b => qb);
end generate;
case_nobe_dual : if (g_with_byte_enable = false and g_dual_clock = true) generate
memory : altsyncram
generic map(
byte_size => 8,
numwords_a => g_size,
numwords_b => g_size,
widthad_a => c_addr_width,
widthad_b => c_addr_width,
width_a => g_data_width,
width_b => g_data_width,
operation_mode => "DUAL_PORT",
read_during_write_mode_mixed_ports => diffport_order,
outdata_reg_a => "UNREGISTERED",
outdata_reg_b => "UNREGISTERED",
address_reg_b => "CLOCK1",
wrcontrol_wraddress_reg_b => "CLOCK1",
byteena_reg_b => "CLOCK1",
indata_reg_b => "CLOCK1",
rdcontrol_reg_b => "CLOCK1",
init_file => c_init_file)
port map(
clock0 => clka_i, wren_a => wea_i,
address_a => aa_i,
data_a => da_i,
clock1 => clkb_i,
address_b => ab_i,
q_b => qb);
end generate;
case_nobe_single : if (g_with_byte_enable = false and g_dual_clock = false) generate
memory : altsyncram
generic map(
byte_size => 8,
numwords_a => g_size,
numwords_b => g_size,
widthad_a => c_addr_width,
widthad_b => c_addr_width,
width_a => g_data_width,
width_b => g_data_width,
operation_mode => "DUAL_PORT",
read_during_write_mode_mixed_ports => diffport_order,
outdata_reg_a => "UNREGISTERED",
outdata_reg_b => "UNREGISTERED",
address_reg_b => "CLOCK0",
wrcontrol_wraddress_reg_b => "CLOCK0",
byteena_reg_b => "CLOCK0",
indata_reg_b => "CLOCK0",
rdcontrol_reg_b => "CLOCK0",
init_file => c_init_file)
port map(
clock0 => clka_i,
wren_a => wea_i,
address_a => aa_i,
data_a => da_i,
address_b => ab_i,
q_b => qb);
end generate;
end syn;