task-to stop counter when it reaches "0000"

Why not simply replacing:

if(enable='1')

with:

if (enable='1') and (counter /= "0000") ?

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How about posting your first attempt, and tell us whats wrong...

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after the code is compiled when i go for simulation i set the end time as 400ns.. at the rising edge when enable is high the counter starts counting. then when it reaches 0000 it again gets loaded with 1111 and starts counting again.. i dont want the counter to count again even if enable is high..

hii did it.. after simulation the counts appear like this... " F E C D C A B A 8 9 8 6 7 6 4 5 4 2 3 2 0 1 0"

I hve set the end time as 400 ns and start is 0 ps..

wt to do to get proper count..? plzz help

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Why not simply replacing:

if(enable='1')

with:

if (enable='1') and (counter /= "0000") ?

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hii did it.. after simulation the counts appear like this... " F E C D C A B A 8 9 8 6 7 6 4 5 4 2 3 2 0 1 0"

I hve set the end time as 400 ns and start is 0 ps..

wt to do to get proper count..? plzz help

why not post the code you used....

And what is the "proper count"? the code you origionally posted is a down counter.

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And what is the "proper count"? the code you origionally posted is a down counter.

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I guess he refers to the glitches (or whatever they are) he obtains in the counter every time he has a 1 to 0 transition on bit 0.

@Naeem

add this: signal counter_out<= std_logic_vector(3 downto 0);

and assign: counter_out <= counter;

This way counter_out should display the proper count

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why not post the code you used....

And what is the "proper count"? the code you origionally posted is a down counter.

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library ieee;

use ieee.std_logic_1164.all;

use ieee.std_logic_unsigned.all;

entity dwncounter is

port( clk,rst:in std_logic;

enable:in std_logic;

count:out std_logic_vector(3 downto 0)

);

end dwncounter;

architecture behavioral of dwncounter is

signal counter:std_logic_vector(3 downto 0):="1111"

begin

process(clk,rst)

begin

if (rst='1') then

counter<=(others=>'0');

elsif rising_edge(clk) then

if(enable='1'and counter/="0000") then

counter<=counter-1;

end if;

end if;

end process;

count<=counter;

end behavioral;

Your code shows a down counter that only counts when enable is high and counter is not 0.

What about a testbench?

where does the clk come from?

shouldnt you be resetting counter to "1111" rather than "0000"?