User Constraints File

John S. OP #1582613
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What dose it mean by User Constraints File?
I wrote the following program for seven segment display driver using 
Xilinx CoolRunner starter kit-
LIBRARY ieee;
USE ieee.std_logic_1164.all;
ENTITY seg7 IS
PORT (D       : IN  STD_LOGIC_VECTOR (3 DOWNTO 0);
      S       : OUT STD_LOGIC_VECTOR (6 DOWNTO 0));
END seg7;
ARCHITECTURE display OF SEG7 IS
BEGIN
s <=  "1000000" WHEN d = "0000" ELSE -- H"40"
      "1111001" WHEN d = "0001" ELSE -- H"79"
      "0100100" WHEN d = "0010" ELSE -- H"24"
      "0110000" WHEN d = "0011" ELSE -- H"30"
      "0011001" WHEN d = "0100" ELSE -- H"19"
      "0010010" WHEN d = "0101" ELSE -- H"12"
      "0000010" WHEN d = "0110" ELSE -- H"02"
      "1111000" WHEN d = "0111" ELSE -- H"78"
      "0000000" WHEN d = "1000" ELSE -- H"00"
      "0010000" WHEN d = "1001" ELSE -- H"10"
      "0001000" WHEN d = "1010" ELSE -- H"08"
      "0000011" WHEN d = "1011" ELSE -- H"03"
      "1000110" WHEN d = "1100" ELSE -- H"46"
      "0100001" WHEN d = "1101" ELSE -- H"21"
      "0000110" WHEN d = "1110" ELSE -- H"06"
      "0001110";                     -- H"0E"
END display;

But what will be the User Constraints File for it?
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na sowas Guest #1582696
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In the User Constraints File you e.g. assign pins to your top entity 
port and in this file you specify a desired clock rate.

BTW:
1
s <=  "1000000" WHEN d = "0000" ELSE -- H"40"

2
      "1111001" WHEN d = "0001" ELSE -- H"79"

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      "0100100" WHEN d = "0010" ELSE -- H"24"

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      :

this you could write a little more readable:
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s <=  x"40" WHEN d = x"0" ELSE 

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      x"79" WHEN d = x"1" ELSE 

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      x"24" WHEN d = x"2" ELSE 

4
      :

5
      x"06" WHEN d = x"E" ELSE 

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      x"0E"
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John S. OP #1585193
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Thanks...
But the problem is that after implementing this code it created a .JED 
file for the CoolRunner II but nothing was happening.Then I realized 
that I have to make an .UCF file for that project.But I really don't 
know how to make one for my program.So can u plz advice what shall I 
do??
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na sowas Guest #1585235
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> But I really don't know how to make one for my program.
> So can u plz advice what shall I do??
Go to the Processes and click on Assign Package Pins. Then you will be 
asked to add a ucf file to your design. And after starting the Wizzard 
(PACE) you can assign the pins simply by Drag&Drop.
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na sowas Guest #1586603
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> If possible I need ur suggestion?And thank u again...
What kind of speaker do you have?

Usually thats the way:
Generate a audible frequency with a counter. Connect it to the speaker 
pins. When the button is not pressed reset the counter, so theres 
nothing to hear...
1
:

2
use ieee.numeric_std.all

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:

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  port ( clk : in std_logic;

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         btn : in std_logic;

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         spkr : out std_logic);

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:

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 signal counter : integer range 0 to 10_000_000/1600 := 0; -- clk-frequency = 10Mhz, speaker output = 800Hz

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 signal intspkr : std_logic := '0';

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:

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 process begin

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    wait until rising_edge(clk);

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    if (counter<10_000_000/1600) then -- reached end of counter?

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       counter <= counter+1;          -- no:  increment  

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    else 

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       counter <= 0;                  -- yes: reset counter

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       intspkr <= not intspkr;        --      toggle output

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    end if;

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    if (btn='0') then  -- button not pressed:  

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       counter <= 0;   -- reset counter

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    end if;

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 end process;

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 spkr <= intspkr;

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:
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