一般按鍵延時在20ms左右，根據時鐘頻率決定你的計數范圍。程序非常簡單，但經常用到，對于FPGA初學者要好好學習這部分。

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;

entity reseter is
port(clk,reset_in:in std_logic;           --按鍵按下時為0
     reset_out:out std_logic:='0');
      end reseter;

architecture behav of reseter is

begin

PROCESS(clk,reset_in) 
  VARIABLE COUNT1 :INTEGER RANGE 0 TO 100000; 
BEGIN 
IF reset_in='0' THEN 
   IF RISING_EDGE(clk) THEN
    IF COUNT1<10000 THEN COUNT1:=COUNT1+1; 
    ELSE COUNT1:=COUNT1; END IF; 
    IF COUNT1<=9999 THEN reset_out<='1'; 
    ELSE reset_out<='0'; END IF; 
  END IF; 
ELSE COUNT1:=0;
     reset_out<='1';
END IF; 
END PROCESS ;
end behav;```