USB fT245 max II

i have already read all datasheet, the device works with TXE and WR, this is my program

-- usb_ft245.vhd

-- 09/05/011

-- J.C. Hdz De Torres

LIBRARY IEEE;

USE IEEE.STD_LOGIC_1164.ALL;

USE IEEE.STD_LOGIC_ARITH.ALL;

USE IEEE.STD_LOGIC_UNSIGNED.ALL;

ENTITY usb_ft245 IS

PORT(

clk : IN STD_LOGIC;---------- contador

data_port: INOUT STD_LOGIC_VECTOR(7 DOWNTO 0);

INPUTS: IN STD_LOGIC_VECTOR(7 DOWNTO 0);

OUTPUTS: OUT STD_LOGIC_VECTOR(7 DOWNTO 0);

LECTURA: IN STD_LOGIC;

A: IN STD_LOGIC;

RD: OUT STD_LOGIC;

WR: OUT STD_LOGIC;

RXF: IN STD_LOGIC;

TXE: IN STD_LOGIC);

END usb_ft245;

ARCHITECTURE usb_driver OF usb_ft245 IS

SIGNAL data_in : STD_LOGIC_VECTOR(7 DOWNTO 0);

SIGNAL data_out : STD_LOGIC_VECTOR(7 DOWNTO 0);

SIGNAL read_or_write : STD_LOGIC;

--------señales del contador------------------------

SIGNAL contador_periodo : STD_LOGIC_VECTOR(16 DOWNTO 0);

SIGNAL lectura_signal : STD_LOGIC;

BEGIN

PROCESS

BEGIN

WAIT UNTIL(clk'EVENT) AND (clk='1');

--the antity is ready to send a byte.

--Find out if the ft245 is ready to receive a byte

---IF (LECTURA = '1') THEN

WR <= '0';

IF (TXE = '0') THEN -- to send data from the peripheral to the host

IF (LECTURA = '1') THEN----------------------------------------------------

data_in <= INPUTS; ---carga los datos en e host

data_port <= data_in;

IF(contador_periodo >= 10 AND contador_periodo < 15)

THEN WR <= '1';

ELSE

WR <= '0';

END IF;

--Reset del contador

IF (contador_periodo = (23)) THEN

contador_periodo <= "00000000000000000";

ELSE

contador_periodo <= contador_periodo + 1;

END IF;

else--------------------

data_port<="ZZZZZZZZ";--------------------------

END IF;

END IF;

END PROCESS;

END usb_driver;

but the signal TXE doesnt seem to datasheet , it has something like noise,

the yellow signal is TXE, WR is blue

http://www.alteraforum.com/forum/attachment.php?attachmentid=4552&stc=1&d=1313505805