自动售货机VHDL程序-通信工程毕业论文

（1）自动售货机VHDL程序如下：
--文件名：pl_auto1.vhd。
--功能：货物信息存储，进程控制，硬币处理，余额计算，显示等功能。
--说明：显示的钱数coin的 以5角为单位。
--最后修改日期：2004.3.23。
library ieee;
use ieee.std_logic_arith.all;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
entity PL_auto1 is
port ( clk:in std_logic;                              --系统时钟
 set,get,sel,finish: in std_logic;                   --设定、买、选择、完成信号
 coin0,coin1: in std_logic;                      --5角硬币、1元硬币
 price,quantity  :in std_logic_vector(3 downto 0);   --价格、数量数据
 item0 , act:out std_logic_vector(3 downto 0);       --显示、开关信号
 y0,y1 :out std_logic_vector(6 downto 0);          --钱数、商品数量显示数据
 act10,act5   :out std_logic);                   --1元硬币、5角硬币
end PL_auto1;
architecture behav of PL_auto1 is
type  ram_type is array(3 downto 0)of std_logic_vector(7 downto 0);
signal ram :ram_type;                                      --定义RAM
signal item: std_logic_vector(1 downto 0);                      --商品种类 （转载自http://www.ＮＳＥＡＣ.com中国科教评价网）
signal coin: std_logic_vector(3 downto 0);                      --币数计数器
signal pri,qua:std_logic_vector(3 downto 0);                    --商品单价、数量
signal clk1: std_logic;                                      --控制系统的时钟信号
begin
com:process(set,clk1)
variable quan:std_logic_vector(3 downto 0);
begin
  if set='1' then ram(conv_integer(item))<=price & quantity;act<="0000";
 --把商品的单价、数量置入到RAM
  elsif clk1'event and clk1='1' then  act5<='0'; act10<='0';
      if coin0='1' then    
      if coin<"1001"then coin<=coin+1;            --投入5角硬币，coin自加1
   else coin<="0000";
   end if;
      elsif coin1='1' then
   if coin<"1001"then coin<=coin+2;            --投入1元硬币，coin自加2
   else coin<="0000";
   end if;
      elsif sel='1' then item<=item+1;                  --对商品进行循环选择
 elsif get='1' then                              --对商品进行购买 本文来自中国科教评价网
 if qua>"0000" and coin>=pri then coin<=coin-pri;quan:=quan-1;
 ram(conv_integer(item))<=pri & quan;
            if   item="00" then act<="1000";  --购买时，自动售货机对4种商品的操作
   elsif item="01" then act<="0100";
      elsif item="10" then act<="0010";
      elsif item="11" then act<="0001";
   end if;
  end if;
      elsif  finish='1' then                            --结束交易，退币（找币）
         if coin>"0001" then act10<='1';coin<=coin-2;     --此IF语句完成找币操作
         elsif coin>"0000" then act5<='1'; coin<=coin-1;
         else act5<='0'; act10<='0';
         end if;
      elsif get='0' then act<="0000";                 
         for i in 4 to 7 loop                   
         pri(i-4)<=ram (conv_integer(item))(i);           --商品单价的读取
         end loop;
         for i in 0 to 3 loop
         quan(i):=ram(conv_integer(item))(i);            --商品数量的读取 （转载自http://zw.ＮＳＥaＣ.com科教作文网）
         end loop;
      end if;
  end if;
 qua<=quan;
end process com;

m32:process(clk)                            --此进程完成对32Mhz的脉冲分频
variable q: std_logic_vector( 24 downto 0);
begin
   if clk'event and clk='1' then q:=q+1;
   end if;
   if q="111111111111111111111111" then clk1<='1';
   else clk1<='0';
   end if;
end process m32;

code0:process(item)                          --商品指示灯译码
begin
 case item is
 when "00"=>item0<="0111";
 when "01"=>item0<="1011";
 when "10"=>item0<="1101";
 when others=>item0<="1110";
 end case;
end process;

code1: process (coin)                       --钱数的BCD到七段码的译码
begin
  case coin is
      when "0000"=>y0<="0000001";
      when "0001"=>y0<="1001111";
      when "0010"=>y0<="0010010";
      when "0011"=>y0<="0000110";
      when "0100"=>y0<="1001100";
      when "0101"=>y0<="0100100";
      when "0110"=>y0<="0100000";
      when "0111"=>y0<="0001111";
      when "1000"=>y0<="0000000"; （转载自科教范文网http://fw.nseac.com）
      when "1001"=>y0<="0000100";
      when others=>y0<="1111111";
  end case;
end process;

code2: process (qua)                       --单价的BCD到七段码的译码
begin
  case qua is
      when "0000"=>y1<="0000001";
      when "0001"=>y1<="1001111";
      when "0010"=>y1<="0010010";
      when "0011"=>y1<="0000110";
      when "0100"=>y1<="1001100";
      when "0101"=>y1<="0100100";
      when "0110"=>y1<="0100000";
      when "0111"=>y1<="0001111";
      when "1000"=>y1<="0000000";
      when "1001"=>y1<="0000100";
      when others=>y1<="1111111";
  end case;
end process;
end behav;