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Forum: FPGA, VHDL & Verilog counter with signal enable (active high) and synchronous reset signal (active high)


counter with signal enable (active high) and synchronous reset signal (active high)
von Juan (Guest)

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I'm trying to do the following task, but I need your help or some 
pointers:

Write a counter with signal enable (active high) and synchronous reset 
signal (active high) to a VHDL file (cont_clk.vhd).
The counter should generate an end of count (rco) output signal that 
turns high every 1 millisecond and which is active for one clock cycle 
(clk). It should also generate a count signal (q) of 14 bits.

Use the counter scheme (sequential circuit) described below.

The module should have the following entity declaration:

entity cont_clk is
 Port (enable: in STD_LOGIC;
 reset: in STD_LOGIC;
 clk: in STD_LOGIC;
 rco: out STD_LOGIC;
 q: out STD_LOGIC_VECTOR (13 down 0));
end cont_clk;

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Re: counter with signal enable (active high) and synchronous reset signal (active high)
von Homework_Service @ Nightshift (Guest)

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1
library IEEE;

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use IEEE.STD_LOGIC_1164.ALL;

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use IEEE.NUMERIC_STD.ALL;

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entity cont_clk is Port(

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  enable: in std_logic;

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  reset: in std_logic;

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  clk: in std_logic;

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  rco: out std_logic;

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  q: out std_logic_vector(13 downto 0));

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end cont_clk;

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architecture Behavioral of cont_clk is

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constant M: integer:=999999;

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signal Data: std_logic_vector(13 downto 0):=(others => '0');

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signal rco_buffer: std_logic:='0';

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begin

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q <= Data;

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rco_buffer <= '1' when to_integer(unsigned(Data)) = M else '0';

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rco <= rco_buffer;

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process begin

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  wait until rising_edge(clk);

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  if reset = '1' then

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

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  else

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    if enable = '1' then

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      if rco_buffer = '0' then

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        Data <= std_logic_vector(unsigned(Data) +1);

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      else

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

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      end if;

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    end if;

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  end if;

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end process;

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end Behavioral;


Juan wrote:
> The counter should generate an end of count (rco) output signal that
> turns high every 1 millisecond

Depends on:
Clock frequency.

  


  




  

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    Re: counter with signal enable (active high) and synchronous reset signal (active high)
  


  

    

      von
      
        Homework_Service @ Nightshift (Guest)
      
      


      
    


    

      
    

    

    

  
  


  

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Homework_Service @ Nightshift wrote:
> constant M: integer:=999999;

Too high. Choose Clock frequency <= 1/(1 ms/2**14) <= 16.38 MHz. And M 
<= 2**14-1.

  


  




  

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