-- File: upcnt4.vhd
--
-- Author: Jennifer Jenkins
-- Philips Semiconductor
-- Purpose: Up 4-bit counter
--
-- Created: 5-3-99 JLJ
-- Revised: 6-15-99 ALS
library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.std_logic_arith.all;
entity upcnt4 is
port(
data : in STD_LOGIC_VECTOR (3 downto 0); -- Serial data in
cnt_en : in STD_LOGIC; -- Count enable
load : in STD_LOGIC; -- Load line enable
clr : in STD_LOGIC; -- Active low clear
clk : in STD_LOGIC; -- Clock
qout : inout STD_LOGIC_VECTOR (3 downto 0)
);
end upcnt4;
architecture DEFINITION of upcnt4 is
constant RESET_ACTIVE : std_logic := '0';
signal q_int : UNSIGNED (3 downto 0);
begin
process(clk, clr)
begin
-- Clear output register
if (clr = RESET_ACTIVE) then
q_int '0');
-- On falling edge of clock count
elsif (clk'event) and clk = '1' then
-- Load in start value
if (load = '1') then
q_int -- If count enable is high
elsif cnt_en = '1' then
q_int end if;
end if;
end process;
qout
end DEFINITION;
