【发布时间】：2016-06-19 21:21:05
【问题描述】：
我有一个学校实验室，我必须在 VHDL 中创建一个顺序乘法器。我的问题是在为顺序乘法器制作有限状态机之前发生的。我无法让基本模型正确乘法，我认为我的测试台有问题，但不能 100% 确定这一点。我仍然怀疑问题出在我的代码中。
顶级设计（基本上称为 D-Flip-Flops、MUX 和 Adder）
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
--use ieee.std_logic_arith.all;
--use ieee.std_logic_unsigned.all;
entity toplvds is
port( A,B: in std_logic_vector(3 downto 0);
Zero: in std_logic_vector(3 downto 0);
clk, clr, load, loadP, sb: in std_logic;
Po: out std_logic_vector(7 downto 0));
end toplvds;
architecture Behavioral of toplvds is
component dffa
port( dina: in std_logic_vector(3 downto 0);
clr, clk, load: in std_logic;
q: out std_logic_vector(3 downto 0));
end component;
component dffb
port( dinb: in std_logic_vector(3 downto 0);
clr, clk, load, sb: in std_logic;
qb0: out std_logic);
end component;
component mux
port( d0,d1: in std_logic_vector(3 downto 0);
s: in std_logic;
y: out std_logic_vector(3 downto 0));
end component;
component adder
port( a,b: in std_logic_vector(3 downto 0);
cry: out std_logic;
r: out std_logic_vector(3 downto 0));
end component;
component dffP
port( dinp: in std_logic_vector(3 downto 0);
carry: in std_logic;
clr, clk, loadP, sb: in std_logic;
PHout: out std_logic_vector (3 downto 0);
P: out std_logic_vector(7 downto 0));
end component;
signal Wire1: std_logic_vector(3 downto 0);
signal Wire2: std_logic_vector(3 downto 0);
signal Wire3: std_logic;
signal Wire4: std_logic_vector(3 downto 0);
signal Wire5: std_logic_vector(3 downto 0);
signal Wire6: std_logic_vector(3 downto 0);
signal Wire7: std_logic;
begin
Wire1 <= Zero;
u1: dffa port map (dina=>A,clr=>clr,clk=>clk,load=>load,q=>Wire2);
u2: dffb port map (dinb=>B,clr=>clr,clk=>clk,load=>load,sb=>sb,qb0=>Wire3);
u3: mux port map (d0=>Wire2,d1=>Wire1,s=>Wire3,y=>Wire4);
u4: adder port map (a=>Wire6,b=>Wire4,cry=>Wire7,r=>Wire5);
u5: dffp port map (dinp=>Wire5,carry=>Wire7,clr=>clr,clk=>clk,loadP=>loadP,sb=>sb,PHout=>Wire6,P=>Po);
end Behavioral;
被乘数的 D 触发器
library ieee;
use ieee.std_logic_1164.all;
entity dffa is
port( dina: in std_logic_vector(3 downto 0);
clr, clk, load: in std_logic;
q: out std_logic_vector(3 downto 0));
end dffa;
architecture beh of dffa is
begin
process(clk,clr)
begin
if(clr = '1') then
q <= ( others => '0');
elsif (rising_edge(clk)) then
if(load = '1') then
q <= dina;
end if;
end if;
end process;
end beh;
乘数的 D 触发器
library ieee;
use ieee.std_logic_1164.all;
entity dffb is
port( dinb: in std_logic_vector(3 downto 0);
clr, clk, load, sb: in std_logic;
qb0: out std_logic);
end dffb;
architecture beh of dffb is
signal q: std_logic_vector(3 downto 0);
begin
qb0 <= q(0);
process(clk,clr, load, sb)
begin
if(clr = '1') then
q <= ( others => '0');
elsif (rising_edge(clk)) then
if(load = '1') then
q <= dinb;
elsif (sb = '1') then
q <= '0' & q ( 3 downto 1);
end if;
end if;
end process;
end beh;
多路复用器
library ieee;
use ieee.std_logic_1164.all;
entity mux is
port( d0,d1: in std_logic_vector(3 downto 0);
s: in std_logic;
y: out std_logic_vector(3 downto 0));
end mux;
architecture beh of mux is
begin
y <= d0 when s = '1' else d1;
end beh;
加法器
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
use ieee.std_logic_arith.all;
entity adder is
port( a,b: in std_logic_vector(3 downto 0);
cry: out std_logic;
r: out std_logic_vector(3 downto 0));
end adder;
architecture beh of adder is
signal temp : std_logic_vector(4 downto 0);
begin
temp <= ('0' & a) + ('0' & b);
r <= temp(3 downto 0);
cry <= temp(4);
end beh;
产品的 D 触发器
library ieee;
use ieee.std_logic_1164.all;
entity dffp is
port( dinp: in std_logic_vector(3 downto 0);
carry: in std_logic;
clr, clk, loadP, sb: in std_logic;
PHout: out std_logic_vector (3 downto 0);
P: out std_logic_vector(7 downto 0));
end dffp;
architecture beh of dffp is
signal q: std_logic_vector(7 downto 0);
begin
--qp0 <= q(0);
process(clk,clr, loadP, sb)
begin
if(clr = '1') then
q <= ( others => '0');
elsif (rising_edge(clk)) then
if(loadP = '1') then
--q <= "00000000";
q(7 downto 4) <= dinp;
elsif (sb = '1') then
q <= carry & q ( 7 downto 1);
--else
--q(7 downto 4) <= dinp;
end if;
end if;
end process;
PHout <= q(7 downto 4);
P <= q;
end beh;
测试台代码
LIBRARY ieee;
USE ieee.std_logic_1164.ALL;
-- Uncomment the following library declaration if using
-- arithmetic functions with Signed or Unsigned values
--USE ieee.numeric_std.ALL;
ENTITY toplvds_tb IS
END toplvds_tb;
ARCHITECTURE behavior OF toplvds_tb IS
-- Component Declaration for the Unit Under Test (UUT)
COMPONENT toplvds
PORT(
A : IN std_logic_vector(3 downto 0);
B : IN std_logic_vector(3 downto 0);
Zero : IN std_logic_vector(3 downto 0);
clk : IN std_logic;
clr : IN std_logic;
load : IN std_logic;
loadP : IN std_logic;
sb : IN std_logic;
Po : OUT std_logic_vector(7 downto 0)
);
END COMPONENT;
--Inputs
signal A : std_logic_vector(3 downto 0) := (others => '0');
signal B : std_logic_vector(3 downto 0) := (others => '0');
signal Zero : std_logic_vector(3 downto 0) := (others => '0');
signal clk : std_logic := '0';
signal clr : std_logic := '0';
signal load : std_logic := '0';
signal loadP : std_logic := '0';
signal sb : std_logic := '0';
--Outputs
signal Po : std_logic_vector(7 downto 0);
-- Clock period definitions
constant clk_period : time := 10 ns;
BEGIN
-- Instantiate the Unit Under Test (UUT)
uut: toplvds PORT MAP (
A => A,
B => B,
Zero => Zero,
clk => clk,
clr => clr,
load => load,
loadP => loadP,
sb => sb,
Po => Po
);
-- Clock process definitions
clk_process :process
begin
clk <= '0';
wait for clk_period/2;
clk <= '1';
wait for clk_period/2;
end process;
-- Stimulus process
stim_proc: process
begin
A <= "1011";
B <= "1101";
Zero <="0000";
load <= '0';
sb <= '0';
clr <= '1';
wait for 12 ns;
clr <= '0'; load <= '1';
wait for 12 ns;
load <= '0'; sb <= '1';
wait for 12 ns;
sb <= '0'; loadP <= '1';
wait for 12 ns;
loadP <= '0'; sb <= '1';
wait for 12 ns;
sb <= '0'; loadP <= '1';
wait for 12 ns;
loadP <= '0'; sb <= '1';
wait for 12 ns;
sb <= '0'; loadP <= '1';
wait for 12 ns;
loadP <= '0'; sb <= '1';
wait for 12 ns;
sb <= '0'; loadP <= '1';
wait for 12 ns;
loadP <= '0'; sb <= '1';
wait for 20 ns;
loadP <= '0'; sb <= '0';
wait;
end process;
END;
很抱歉，为了更好地理解，我没有对代码进行注释。我知道这将很难遵循，但我希望有人会。我还将附上我正在关注的顺序乘法器的图形，电路设计。
【问题讨论】：
-
您可以通过使用实体语法而不是组件语法来缩短代码：
u1: entity work.dffa port map (dina=>A,clr=>clr,clk=>clk,load=>load,q=>Wire2);。 -
你的很多过程，它们描述了顺序逻辑，例如您的 D-FF 对更多信号敏感，而不仅仅是时钟和可选的异步复位。此外，包
std_logic_arith被认为已弃用，不应再使用。请改用numeric_std。 -
您的文件使用包 numeric_std 和 numeric_std_unsigned (-2008) 进行分析、详细说明和模拟。他们似乎给出了错误的乘法结果。为什么是个人人字拖？
标签： vhdl sequential multiplication circuit