Vhdl codes for counter to start and purse

[Altera_Forum]

Hi, 

 I need urgent help on how to design a stopwatch that can stop/purse using vhdl code. I will really appreciate any urgent reply to this.  Thanks.  Waiting for your replies.

[Altera_Forum]

Use Quartus -> Right click -> Insert template -> Full design -> Counter

[Altera_Forum]

I didnt get what you are saying. 

 I have designed the counter but I want to work on the stop and start botton on the board to stop/start when i press stop/start without holding the button down.  I will need quick reply from you and other members of this forum.

[Altera_Forum]

Add the following lines: 

  --pseudocode -- on the clock edge if start = '1' then -- or may be '0' depending on key logic start_L <= '1'; elsif stop = '1' then start_L <= '0'; end if; if start_L = '1' then count <= count + 1; end if;

[Altera_Forum]

Can you make ce input to be for both start/stop/pause or you separate start, stop and purse as different input logic? 

I will appreciate your urgent reply

[Altera_Forum]

I assume CE is clkenable. You can apply it to all clocked registers at same time.

[Altera_Forum]

can i separate the START AND PURSE with separate input i.e 

 Start: IN_STD_LOGIC PAUSE: IN_STD_LOGIC

[Altera_Forum]

you can start, stop, reset, freeze reverse,...etc at will by choosing a switch for each decision

[Altera_Forum]

is not working out at. I want to the button start to be pressed once and it will purse. I have been able to do it that if i press it down, it will purse. Now I want a code for CLockenable that can stop the counter, like clear it without changing and if i press it again, it should be able to start. 

 Thanks.

[Altera_Forum]

is not working out . I want the button start to be pressed once and it will purse. I have been able to do it such that if i press it down, it will purse. Now I want a code for CLockenable that can stop the counter, like clear it and if i press it again, it should start. 

thanks.

[Altera_Forum]

in that case it should not be called clock enable. 

 -- on clock edge if sw = '1' then toggle <= not toggle; end if;  if toggle = '1' then count <= 0; else count up...  you will need to manage the logic of various switches now with care otherwise they might get in conflict. This where simulations helps.

[Altera_Forum]

how can i design the clock such that if i press pause at intial state, there should be something to remember that state so that Wwhen i do that, the button will change to the next state i.e 1 to 0.

[Altera_Forum]

is majoprly on the start./stop and nothint else. thats all i need for now. 

 Thanks.

[Altera_Forum]

anybody with idea on how to implement this. I need it urgent.  

or If you know how to apply flip flop, logic gate to manipulate the start and stop button, I will appreciate it. Thanks   one switch represent start and stop. All I want is that instead of holding the switch down to stop counting, I want it to stop counting if I also remove my hand. and again If I do same thing, i want it to start counting....  Please If you know what I mean, kindly help me out.  Thanks

[Altera_Forum]

The best way to achieve what you are asking is to draw yourself a flow chart. If you are looking for an on/off button with just one push then you would have something like this. 

  process(clk) begin if(rising_edge(clk)) then button_prev <= button_curr; button_curr <= button; end if; end process Button_pulse <= button_curr AND (NOT button_prev); Now, you can register the pulse, add debounce, ect. It is up to you.   Next, you need to create a state machine to handle the enable to your counter. From what you've described you have 2 states, on and off. you start in the off state, if the button_pulse = 1 then you go to the on state and again if the button pulse is 1 you go back to the off state. Then you describe your counter enable as 1 when in the on state and 0 when in the off. I recommend drawing this out and then creating your state machine to match your diagram.