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debounce code push button

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ashutosh_g

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i use a push button for giving negative reset to my FPGA.
The push button however is bouncy. can any one give me the code for
debouncing the reset signal. so that the internal reset signal goes to zero only once for a stipulated amount of time after pushing the push button .
I need the code in VHDL
 

Hi,
This is simple code.If u know VHDL, u can write. Simply register u'r push button input with repect to clock and generate the negedge pulse and use as a reset for u'r FPGA.
 

Couldn't you solve this with a latch?
 

Here is a code for debouncing push button
Code: 
LIBRARY IEEE;
USE  IEEE.STD_LOGIC_1164.all;
USE  IEEE.STD_LOGIC_ARITH.all;
USE  IEEE.STD_LOGIC_UNSIGNED.all;

	-- Debounce Pushbutton: Filters out mechanical switch bounce for around 40Ms.
ENTITY debounce IS
	PORT(pb, clock_100Hz 	: IN	STD_LOGIC;
		 pb_debounced		: OUT	STD_LOGIC);
END debounce;

ARCHITECTURE a OF debounce IS
	SIGNAL SHIFT_PB 		: STD_LOGIC_VECTOR(3 DOWNTO 0);
BEGIN

	-- Debounce clock should be approximately 10ms or 100Hz
	PROCESS
	BEGIN
  		WAIT UNTIL (clock_100Hz'EVENT) AND (clock_100Hz = '1');
		-- Use a shift register to filter switch contact bounce
  		SHIFT_PB(2 DOWNTO 0) <= SHIFT_PB(3 DOWNTO 1);
  		SHIFT_PB(3) <= NOT PB;
  		IF SHIFT_PB(3 DOWNTO 0)="0000" THEN
   			PB_DEBOUNCED <= '0';
  		ELSE 
   	 		PB_DEBOUNCED <= '1';
  		END IF;
	END PROCESS;
END a;

Cheers ................ kib
 

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