library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
entity jtd is
port (
clk,rst:in std_logic;
row ut std_logic_vector(3 downto 0);
r,y,g ut std_logic
);
end jtd;
architecture one of jtd is
constant y_time :integer:=5;--黄灯时间
constant rg_time:integer:=20;--红绿灯时间
type type_state is(hx_g,hx_y,zx_g,zx_y);--自定义四种状态
signal p :integer range 0 to 3;--扫描计数器
signal state_n :type_state;--当前状态
signal clk_500 :std_logic;--扫描时钟
signal clk_1s :std_logic;--1s时钟
signal r0,y0,g0 :std_logic;--横向路口控制信号
signal r1,y1,g1 :std_logic;--纵向路口控制信号
begin
process(clk)--1kHZ分频
variable cnt1 : integer range 0 to 200;
variable cnt2 : integer range 0 to 250;
begin
if clk'event and clk='1' then
if cnt1=200 then
cnt1:=0;
if cnt2=250 then
cnt2:=0;
clk_500<=not clk_500;
else cnt2:=cnt2+1;
end if;
else cnt1:=cnt1+1;
end if;
end if;
end process;
process(clk_500)--1HZ分频
variable cnt: integer range 0 to 250;
begin
if clk_500'event and clk_500='1' then
if(p=3) then
p<=0;
else p<=p+1;--扫描计数器工作于1KHZ的频率
end if;
if cnt=250 then
cnt:=0;
clk_1s<=not clk_1s;
else cnt:=cnt+1;
end if;
end if;
end process;
process(rst,clk_1s)--交通灯状态控制进程
variable load0,load1: integer;
begin
if rst='0' then
state_n<=hx_g;load0:=rg_time;load1:=rg_time;
r0<='0';y0<='0';g0<='0';
r1<='1';y1<='1';g1<='1';
elsif clk_1s'event and clk_1s='1' then
case state_n is
when hx_g=> if load0=0 then--横向绿灯
load0:=y_time;state_n<=hx_y;
else
load0:=load0-1;
r0<='0';y0<='0';g0<='1';
r1<='1';y1<='0';g1<='0';
end if;
when hx_y=> if load0=0 then--横向黄灯
load1:=y_time;state_n<=zx_y;
else
load0:=load0-1;
r0<='0';y0<='1';g0<='0';
r1<='1';y1<='0';g1<='0';
end if;
when zx_y=> if load1=0 then--纵向黄灯
load1:=rg_time;state_n<=zx_g;
else load1:=load1-1;
r0<='1';y0<='0';g0<='0';
r1<='0';y1<='1';g1<='0';
end if;
when zx_g=>if load1=0 then--纵向绿灯
load0:=rg_time;state_n<=hx_g;
else load1:=load1-1;
r0<='1';y0<='0';g0<='0';
r1<='0';y1<='0';g1<='1';
end if;
when others=>r0<='1';y0<='0';g0<='0';
r1<='1';y1<='0';g1<='0';
state_n<=hx_g;
load0:=rg_time;load1:=rg_time;
end case;
end if;
end process;
process(p)--交通灯扫描进程
begin
case p is
when 0=>row<="1110";r<=r0;y<=y0;g<=g0;
when 1=>row<="1101";r<=r1;y<=y1;g<=g1;
when 2=>row<="1011";r<=r0;y<=y0;g<=g0;
when 3=>row<="0111";r<=r1;y<=y1;g<=g1;
end case;
end process;
end one;
ut std_logic_vector(3 downto 0);
附件: jtd.rar (2010-4-30 11:25, 1.03 KB) / 下载次数 408