count_money.vhd

基于fpga的出租车计费系统

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
entity count_money is
port( clkin : in std_logic;
      dip : in std_logic_vector(1 downto 0);
      money : out std_logic_vector(9 downto 0));
end entity;
architecture behav of count_money is
  signal qibu : std_logic_vector(9 downto 0);
  signal temp0,temp1 : std_logic_vector(9 downto 0);
begin
  with dip select
     qibu <=  conv_std_logic_vector(5,10) when "00",
              conv_std_logic_vector(6,10) when "01",
              conv_std_logic_vector(8,10) when "10",
              conv_std_logic_vector(10,10) when "11";
  process(clkin,temp0,temp1)
  begin
    if rising_edge(clkin) then
      temp0<=temp0+'1';
    end if;
  end process;
  money<=qibu when temp0<=qibu else temp0;
end behav;