Subversion Repositories debouncer_vhdl

----------------------------------------------------------------------------------

-- Author:          Jonny Doin, jdoin@opencores.org, jonnydoin@gmail.com

-- 

-- Create Date:     01:21:32 06/30/2011 

-- Design Name: 

-- Module Name:     debounce_atlys_top

-- Project Name:    debounce_vhdl

-- Target Devices:  Spartan-6 LX45

-- Tool versions:   ISE 13.1

-- Description: 

--

--          This is a verification project for the Digilent Atlys board, to test the GRP_DEBOUNCE core.

--          It uses the board's 100MHz clock input, and clocks all sequential logic at this clock.

--

--          See the "debounce_atlys.ucf" file for pin assignments.

--          The test circuit uses the VHDCI connector on the Atlys to implement a 16-pin debug port to be used

--          with a Tektronix MSO2014. The 16 debug pins are brought to 2 8x2 headers that form a umbilical

--          digital pod port.

--          If you want details of the testing circuit, send me an e-mail: jdoin@opencores.org

--

------------------------------ REVISION HISTORY -----------------------------------------------------------------------

--

-- 2011/08/10   v1.01.0025  [JD]    changed to test the grp_debouncer.vhd module alone.

-- 2011/08/11   v1.01.0026  [JD]    reduced switch inputs to 7, to save digital pins to the strobe signal.

--

--

----------------------------------------------------------------------------------

library ieee;

use ieee.std_logic_1164.all;

use ieee.std_logic_arith.all;

entity debounce_atlys_top is

    Port (

        gclk_i : in std_logic := 'X';               -- board clock input 100MHz

        --- input slide switches ---            

        sw_i : in std_logic_vector (6 downto 0);    -- 7 input slide switches

        --- output LEDs ----            

        led_o : out std_logic_vector (6 downto 0);  -- 7 output leds

        --- debug outputs ---

        dbg_o : out std_logic_vector (15 downto 0)  -- 16 generic debug pins

    );

end debounce_atlys_top;

architecture rtl of debounce_atlys_top is

    --=============================================================================================

    -- Constants

    --=============================================================================================

    -- debounce generics

    constant N          : integer   := 7;           -- 7 bits (7 switch inputs)

    constant CNT_VAL    : integer   := 5000;        -- debounce period = 1000 * 10 ns (50 us)

    --=============================================================================================

    -- Signals for internal operation

    --=============================================================================================

    --- switch debouncer signals ---

    signal sw_data          : std_logic_vector (6 downto 0) := (others => '0'); -- debounced switch data

    signal sw_reg           : std_logic_vector (6 downto 0) := (others => '0'); -- registered switch data 

    signal sw_new           : std_logic := '0';

    -- debug output signals

    signal leds_reg         : std_logic_vector (6 downto 0) := (others => '0');

    signal dbg              : std_logic_vector (15 downto 0) := (others => '0');

begin

    --=============================================================================================

    -- COMPONENT INSTANTIATIONS FOR THE CORES UNDER TEST

    --=============================================================================================

    -- debounce for the input switches, with new data strobe output

    Inst_sw_debouncer: entity work.grp_debouncer(rtl)

        generic map (N => N, CNT_VAL => CNT_VAL)

        port map(

            clk_i => gclk_i,                        -- system clock

            data_i => sw_i,                         -- noisy input data

            data_o => sw_data,                      -- registered stable output data

            strb_o => sw_new                        -- transition detection

        );

    --=============================================================================================

    --  REGISTER TRANSFER PROCESSES

    --=============================================================================================

    -- data registers: synchronous to the system clock

    dat_reg_proc : process (gclk_i) is

    begin

        -- transfer switch data when new switch is detected

        if gclk_i'event and gclk_i = '1' then

            if sw_new = '1' then                    -- clock enable

                sw_reg <= sw_data;                  -- only provide local reset for the state registers

            end if;

        end if;

    end process dat_reg_proc;

    --=============================================================================================

    --  COMBINATORIAL LOGIC PROCESSES

    --=============================================================================================

    -- LED register update

    leds_reg_proc: leds_reg <= sw_reg;              -- leds register is a copy of the updated switch register

    -- update debug register

    dbg_in_proc:    dbg(6 downto 0) <= sw_i;        -- lower debug port has direct switch connections

    dbg_out_proc:   dbg(13 downto 7) <= sw_data;    -- upper debug port has debounced switch data

    dbg_strb_proc:  dbg(14) <= sw_new;              -- monitor new data strobe

    --=============================================================================================

    --  OUTPUT LOGIC PROCESSES

    --=============================================================================================

    -- connect leds_reg signal to LED outputs

    led_o_proc: led_o <= leds_reg;              -- drive the output leds

    --=============================================================================================

    --  DEBUG LOGIC PROCESSES

    --=============================================================================================

    -- connect the debug vector outputs

    dbg_o_proc: dbg_o <= dbg;                   -- drive the logic analyzer port

end rtl;