VHDL code for Button OnRelease

[CJ199]

I am having trouble making the code for kind of an OnRelease function

When a button is pressed there will be a '0' bit when not pressed there will be a '1' bit. I need to wait for the button to be pressed, and then to wait for it to be release before anything happens.... can someone please
help?

***load is the signal from the button

begin
	if(Reset='1') then timer:="0000"; load_count:="00"; 
	elsif(CLK'event and CLK='1') then

	    if(launch_in='1') then GAMEOVER<='1';
		
	    elsif(load='0' and load_count="00") then		
			--if (load='1') then
				timer:=data_in;
				load_count:="01";
			--end if;
								
		elsif(load='0' and load_count="01") then
			--if(load='1') then
				start_temp:='1';
				load_count:="10";
			--end if;
				
		elsif(load='0' and load_count="10") then
			--if(load='1') then
				pause_temp:='1';
				load_count:="11";
			--end if;
		
		elsif(load='0' and load_count="11") then
			--if(load='1') then
				pause_temp:='0';
				load_count:="00";
			--end if;

		end if;		
	end if;

 

[VHDLguy]

I usually do that kind of thing with a shift register. Of course it depends on all kinds of things, like how often the button is to be pressed, and what kind of debounce you might need. For a physical button you probably need a very large debounce of say 250ms or more, unless that is built in already somewhere.

but the idea is:

buttonHistory <= buttonHistory(3 downto 1) & button;

if (buttonHistory = "1110") then
--whatever you want to do when button is pressed

elsif (buttonHistory = "0001") then
-- whatever you want to do on release.


of course with a bounce that won't work just right, so you might need to modify it to something like

if (buttonHistory = "1111") then
status <= '1';
elsif (buttonHistory = "0000") then
status <= '0';
end if;

statusHistory <= statusHistory(0) & status;

if statusHistory = "10" then
-- button press with 4 clocks of debounce.
-- do you stuff here.
elsif statusHistory = "01" then
-- button release with 4 clocks of debounce.
-- do your stuff here.

of course there are lots of ways you could do that. but there is an example.


--

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