--==========================================================
-- Design units : StopWatchBehave (Entity,Architecture)
--
-- File name    : StopWatchBehave.vhd
--
-- Purpose      : Behavioral description of a StopWatch
--
-- Limitations  : none
--
-- Library      : IEEE
--
-- Dependencies : StopPackage,Pulse Generator,StopWatchBehave,StopWatchStruc
--
-- Author       : Claus-Juergen Thomas, REFT
--
-- Simulator    : Synopsys V3.1a on SUN SPARCstation 10
--
-----------------------------------------------------------
-- Revision list
-- Version Author Date           Changes
--
--  v 1.0  cjt    18.01.96       new
--=========================================================

LIBRARY IEEE;
USE IEEE.std_logic_1164.all;
USE work.ELEMpack.all;

ENTITY StopWatchBehave IS
PORT(StartStop  : IN  std_logic;
     Reset      : IN  std_logic;
     Clk        : IN  std_logic;
     Tenths_out : OUT integer;
     Seconds_out: OUT integer;
     Tens_out   : OUT integer);
END StopWatchBehave;

--============================ARCHITECTURE==================

ARCHITECTURE Behavior OF StopWatchBehave IS

SIGNAL tenths,seconds,tens,counter:integer:=0;


BEGIN

main: PROCESS (Clk,Reset)

  BEGIN

    IF StartStop = '1' THEN
      IF StartStop'EVENT THEN
        Tenths <= 0;
      END IF;
      IF Clk'EVENT AND Clk = '1' THEN
        Tenths <= tenths + 1;
        IF Tenths = 9 THEN
          Seconds <= Seconds + 1;
          Tenths <= 0;
          IF Seconds = 9 THEN
            Tens <= Tens + 1;
            Seconds <= 0;
            IF Tens = 5 THEN
              Tens <= 0;
            END IF;
          END IF;
        END IF;
      END IF;
    END IF;

    IF Reset = '0' THEN
      Tenths <= 0;
      Seconds <= 0;
      Tens <= 0;
    END IF;

END PROCESS;

Tenths_out <= Tenths;
Seconds_out <= Seconds;
Tens_out <= Tens;

END Behavior;