数字钟.txt

来自「大学VHDL实验数字钟源码」· 文本 代码 · 共 56 行

library IEEE; 
use IEEE.std_logic_1164.all; 
use IEEE.std_logic_arith.all; 
use IEEE.std_logic_signed.all; 

entity myclock is 
port ( 
clk_1khz : in std_logic; 
reset : in std_logic; 
second : out std_logic_vector (5 downto 0); 
minite : out std_logic_vector (5 downto 0); 
hour : out std_logic_vector (3 downto 0) 
); 
end myclock; 

architecture rtl of myclock is 

begin 
process (clk_1khz, reset) 

variable ms : std_logic_vector(9 downto 0); 
variable mysecond, myminite : std_logic_vector(5 downto 0); 
variable myhour : std_logic_vector(3 downto 0); 

begin 

if reset = '1' then 
mysecond := "000000"; 
myminite := "000000"; 
myhour := "0000"; 
ms := (others =>'0'); 
elsif clk_1khz'event and clk_1khz = '1' then 
-- count ms to 1000 
ms :=ms+1; 
if ms = "1111101000" then 
ms := (others => '0'); 
mysecond := mysecond+1; 
if mysecond = "111100" then 
mysecond := "000000"; 
myminite := myminite + 1; 
if myminite = "111100" then 
myminite := "000000"; 
myhour := myhour + 1; 
if myhour = "1100" then 
myhour := "0000"; 
end if; 
end if; 
end if; 
end if; 
end if; 

second <= mysecond; 
minite <= myminite; 
hour <= myhour; 
end process; 
end architecture;