taxi.txt

费用的计算是按行驶的里程收费

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
entity taxi is
port ( clk_256  :in std_logic;                                              
       start :in std_logic;                              
       stop:in std_logic;                                
       fin:in std_logic;                                 
       cha3,cha2,cha1,cha0:out std_logic_vector(3 downto 0);
       km1,km0:out std_logic_vector(3 downto 0);                   
       min1,min0: out std_logic_vector(3 downto 0));     
end taxi;
architecture behav of taxi is
signal f_15,f_13,f_1:std_logic;                      
signal q_13:integer range 0 to 12;                    
signal q_15:integer range 0 to 14;                     
signal q_1:integer range 0 to 255;                     
signal w:integer range 0 to 59;                       
signal c3,c2,c1,c0:std_logic_vector(3 downto 0); 
signal k1,k0:std_logic_vector(3 downto 0);        
signal m1:std_logic_vector (3 downto 0);
signal m0:std_logic_vector (3 downto 0);
signal en1,en0,f:std_logic;                   
begin

feipin:process(clk_256,start)
begin
  if clk_256'event and clk_256='1' then
    if start='0' then q_15<=0;q_13<=0;f_15<='0';f_13<='0';f_1<='0';f<='0';
    else
      if q_15=14 then q_15<=0;f_15<='1';       
      else q_15<=q_15+1;f_15<='0';
      end if;
      if q_13=12then q_13<=0;f_13<='1';        
      else q_13<=q_13+1;f_13<='0'; 
      end if;
      if q_1=194 then q_1<=0;f_1<='1';       
      else q_1<=q_1+1;f_1<='0';
      end if;
      if en1='1' then f<=f_13;                 
      elsif en0='1' then f<=f_15;
      else f<='0';
      end if;
    end if;
  end if;
end process;

process(f_1)
begin
  if f_1'event and f_1='1' then
    if start='0' then 
w<=0;en1<='0';en0<='0';m1<="0000";m0<="0000";k1<="0000";k0<="0000";
    elsif stop='1' then
      if w=59 then w<=0;                          
        if m0="1001" then m0<="0000";              
          if m1="0101" then m1<="0000";
          else m1<=m1+1;
          end if;
        else m0<=m0+1;
        end if;
        if m1&m0>"0000001"then en1<='1';  
        else en1<='0';
        end if;
      else w<=w+1;en1<='0';
      end if;
    elsif fin='1' then 
      if k0="1001" then k0<="0000";     
        if k1="1001" then k1<="0000";
        else k1<=k1+1;
        end if;
      else k0<=k0+1;
      end if;
      if k1&k0>"00000010" then en0<='1';     
      else en0<='0';
      end if;        
    else en1<='0';en0<='0';
    end if;
cha3<=c3;cha2<=c2;cha1<=c1;cha0<=c0;        
km1<=k1;km0<=k0;min1<=m1;min0<=m0;        
  end if;
end process;

process(f,start)
begin
  if start='0' then c3<="0000";c2<="0000";c1<="0101";c0<="0000";
  elsif f'event and f='1' then
    if c0="1001" then c0<="0000";                     
      if c1="1001" then c1<="0000";
        if c2="1001" then c2<="0000";
          if c3="1001" then c3<="0000";
          else c3<=c3+1;
          end if;
        else c2<=c2+1;
        end if;
      else c1<=c1+1;
      end if;
    else c0<=c0+1;
    end if;
  end if;
end process;
end behav;