（1）自動售貨機VHDL程序如下：
--檔案名：pl_。
--功能：貨物資訊存儲，進程控制，硬幣處理，餘額計算，顯示等功能。
--說明：顯示的錢數coin的 以5角爲單位。
--最後修改日期：2004.3.23。
library ieee;
use _logic_;
use _logic_;
use _logic_;
entity PL_auto1 is
port ( clk:in std_logic; --系統時鐘
set,get,sel,finish: in std_logic; --設定、買、選擇、完成信號
coin0,coin1: in std_logic; --5角硬幣、1元硬幣
price,quantity :in std_logic_vector(3 downto 0); --價格、數量數據
item0 , act:out std_logic_vector(3 downto 0); --顯示、開關信號
y0,y1 :out std_logic_vector(6 downto 0); --錢數、商品數量顯示數據
act10,act5 :out std_logic); --1元硬幣、5角硬幣
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; --定義RAM
signal item: std_logic_vector(1 downto 0); --商品種類
signal coin: std_logic_vector(3 downto 0); --幣數計數器
signal pri,qua:std_logic_vector(3 downto 0); --商品單價、數量
signal clk1: std_logic; --控制系統的時鐘信號
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";
--把商品的單價、數量置入到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角硬幣，coin自加1
else coin<="0000";
end if;
elsif coin1='1' then
if coin<"1001"then coin<=coin+2; --投入1元硬幣，coin自加2
else coin<="0000";
end if;
elsif sel='1' then item<=item+1; --對商品進行循環選擇
elsif get='1' then --對商品進行購買
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"; --購買時，自動售貨機對4種商品的操作
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 --結束交易，退幣（找幣）
if coin>"0001" then act10<='1';coin<=coin-2; --此IF語句完成找幣操作
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); --商品單價的讀取
end loop;
for i in 0 to 3 loop
quan(i):=ram(conv_integer(item))(i); --商品數量的`讀取
end loop;
end if;
end if;
qua<=quan;
end process com;
m32:process(clk) --此進程完成對32Mhz的脈衝分頻
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) --商品指示燈譯碼
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) --錢數的BCD到七段碼的譯碼
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";
when "1001"=>y0<="0000100";
when others=>y0<="1111111";
end case;
end process;
code2: process (qua) --單價的BCD到七段碼的譯碼
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;