使用状态机的按键消抖[源码分享]

k331922164

使用状态机的按键消抖[源码分享] [复制链接]

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
entity debounce_FSM is
generic (fclk : integer :=50000000);
port(
n_rst : in std_logic;
clk : in std_logic;
key_in : in std_logic; --key is valid by low
pulse : out std_logic --output single pulse
);
end debounce_FSM;
architecture rtl of debounce_FSM is
type m_state is(
idle,
delay,
output,
key_up
);
signal cs,ns: m_state;
signal key_reg : std_logic;
constant n : integer :=fclk/100; --100Hz,means to delay 10 ms
signal delay_cnt : integer range 0 to n-1;
begin
--three section FSM
--timing sequence part of FSM
process(n_rst,clk)
begin
if(n_rst='0')then
cs<=idle;
elsif(clk'event and clk='1')then
cs<=ns;
end if;
end process;
--combination part of FSM
process(cs,key_in,delay_cnt)
begin
case (cs) is
when idle => if(key_in='0')then
ns<=delay; --when key is down
else
ns<=idle;
end if;
when delay => if(delay_cnt=n-1)then
ns<=output;
else
ns<=delay;
end if;
when output => ns<=key_up;
when key_up => if(key_in='1')then --waiting key being up
ns<=idle;
else
ns<=key_up;
end if;
when others => ns<=idle;
end case;
end process;
--register output part of FSM
process(n_rst,clk)
begin
if(n_rst='0')then
key_reg <='0';
delay_cnt<=0;
elsif(clk'event and clk='1')then
case (ns) is
when idle => key_reg <='0';delay_cnt<=0;
when delay => key_reg <='0';delay_cnt<=delay_cnt+1;
when output => if(key_in='0')then
key_reg <='1';
else
key_reg <='0';
end if;
delay_cnt<=delay_cnt;
when key_up => key_reg <='0';delay_cnt<=0;
when others => key_reg <='0';delay_cnt<=0;
end case;
end if;
end process;
pulse<=key_reg;
end rtl;

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john_wang

谢谢楼主分享。看看

k331922164

john_wang 发表于 2014-3-18 11:42
谢谢楼主分享。看看

一起学习，一起分享。

david69

Great! Thank for sharing.

使用状态机的按键消抖[源码分享] [复制链接]

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