TB054
An Introduction to USB Descriptors
with a Game Port to USB Game Pad Translator Example
Author:
Reston Condit
Microchip Technology Inc.
INTRODUCTION
This Technical Brief demonstrates the translation of a
game port game pad to a USB game pad using the
PIC16C765, Microchip's low-speed USB PICmicro®
microcontroller (MCU). The purpose of this Technical
Brief is not only to show the translation of a game pad
to USB, but also to show how to successfully develop
a USB peripheral using the PIC16C765. An understanding of USB descriptors is the foundation for
successful USB peripheral development.
Note:
This Technical Brief is the first in a series
of five technical briefs. This series is
meant to familiarize developers with USB.
For the best understanding of USB, read
the briefs in order: TB054, TB055, TB056,
TB057 and TB058.
USB Basics
All USB communication takes the form of frames sent
over the USB bus. Frames are one-millisecond increments in which the host schedules what device endpoints it will communicate with. At the scheduled time,
the host and device send one another requests, or
data, in the form of packets, which are limited in length
to eight bytes for low-speed devices. All packets are
sent to and received by the device via endpoints. Endpoints are buffers where a device either puts data to
wait for a chance to be sent to the host, or where data
received from the host is stored until the device has a
chance to access the data and utilize it. Low-speed
devices have two endpoints that can be configured by
the device as IN or OUT (with respect to the host).
These are Endpoints 1 and 2. Endpoint 0 is reserved
for control transfers between the host and device. This
is the bidirectional avenue through which the host and
device share administrative data. Enumeration is the
process in which a peripheral describes what type of
device it is to the host, and occurs via Endpoint 0.
2004 Microchip Technology Inc.
USB is a master-slave protocol. In other words, the
host (i.e., PC) directs all communications to and from
the peripherals. Peripherals do not send information to
the host unless the host requests the information. How
does a peripheral tell the host what type of device it is
when it is first connected to the host? The answer lies
in the use of “descriptors,” as described in the following
section.
Descriptors
GENERAL
USB descriptors tend to be the biggest stumbling block
for developers that have been recently introduced to
USB. The purpose of descriptors is to communicate the
identity of a particular peripheral to the host. For
instance, the game pad in this technical brief communicates to the host that it is a two axis, six-button game
pad that sends data to the host via Endpoint 1. A device
does not volunteer this information to the host, rather
the host requests this information when it detects that a
new device has been attached to the USB bus. As
mentioned before, the process in which the host
requests and receives a device's descriptors is called
“enumeration.”
Peripherals have more than one descriptor. Each new
descriptor progressively provides the host more information about the peripheral or about other descriptors
to follow. Descriptors can be thought of as a hierarchy.
The first descriptor, the device descriptor, is very general and conveys the most basic information about the
device. The next descriptor is more specific, and so on,
until the host finally gains all the information it needs to
communicate effectively with the device.
Game pads fall under the Human Interface Device
(HID) class. Mice, keyboards and LED displays are all
examples of other devices that fall into the HID class.
The HID class is unique in that driver support is supplied automatically by Windows® (Windows 98 second
edition and newer) and the Macintosh® operating systems. These operating systems will custom build a
driver whenever they detect a new HID peripheral. The
driver is constructed from the data format conveyed in
the report descriptor received from that device. Developing within the HID class specification is the easiest
way to learn how USB works because the developer
doesn't have to be concerned with writing a driver at the
host end.
DS91054C-page 1
TB054
TYPES
Descriptors general to USB are discussed in Chapter 9
of the USB Specification v1.1. The general descriptors
that pertain to all USB devices are the following:
• Device descriptor – describes the most general
information about a USB device. For instance, it
communicates to the host the product and vendor
ID numbers. It tells the host how many configurations the device has, and how many configuration
descriptors the host must request from the device.
A device can have only one device descriptor.
• Configuration descriptor – describes
information about a specific device configuration.
Included in the configuration descriptor, is the
number of interfaces under the specific
configuration. In essence, an interface is a
feature, therefore, a configuration can be viewed
as a collection of peripheral features. Multiple
configurations can exist for one device. For
instance, if a Power Save mode is desired for a
part, it may have two configurations, Normal
mode and Power Save mode.
• Interface descriptor – tells how many endpoints
a device feature uses. It also declares the class
identity of a device. For the game pad, the class
identity is HID.
• Endpoint descriptor – describes the properties
of an endpoint. These properties are namely
whether the endpoint is an IN or OUT endpoint
and what the endpoint number is. Every endpoint
specified in an interface has its own endpoint
descriptor.
DS91054C-page 2
Descriptors specific to the HID class are discussed in
the “Device Class Definition for HID” document. The
HID descriptors that pertain to describing the game pad
are the following:
• HID descriptor – for a Human Interface Device, a
HID descriptor immediately follows the interface
descriptor and precedes the endpoint descriptor(s). This is done because the HID descriptor
may be associated with more than one endpoint,
and as a result, is higher in the “descriptor hierarchy” than endpoint descriptors. A HID descriptor
identifies additional descriptors specific to the HID
class, namely report descriptors and physical
descriptors.
Note:
The game pad example does not have a
physical descriptor associated with it.
Physical descriptors are never necessary,
they are used to describe the physical
aspects and appearance of a device
mainly for an engineer's reference.
Report descriptor – specifies the data format for a
device. The information that each bit represents in a
data packet is defined in the report descriptor. For the
game pad, certain bits correspond to the logic output of
its buttons. Other bit groupings correspond to the X and
Y-axis positions of the directional pad.
Note:
The
USB
Implementers
Forum
(www.usb.org) is the main web location for
obtaining the USB Specification, Device
Class Definition for HID, HID Usage
Tables, and all other defining documents
pertaining to USB. “USB Complete”,
written by Jan Axelson, presents the USB
protocol in a easy to understand format.
2004 Microchip Technology Inc.
TB054
The Game Pad Report
The device, configuration, interface, HID and endpoint
descriptors are relatively straightforward to create. For
these descriptors, all that is necessary is to create the
descriptors according to the definitions in the USB or
HID specifications. The report descriptor, however, is
not straightforward. There is no set format for a report
descriptor since it is describing the data format for a
peripheral, which can be very different from one peripheral to another. The best way to learn how to create a
report descriptor is to walk through example report
descriptors that have been proven to work. Example 1
shows the report descriptor for the game pad.
EXAMPLE 1:
USB GAME PAD REPORT DESCRIPTOR
0x05, 0x01
;USAGE_PAGE (Generic Desktop)
0x09, 0x05
;USAGE (Gamepad)
0xA1, 0x01
;COLLECTION (Application)
0x09, 0x01
;
USAGE (Pointer)
0xA1, 0x00
;
COLLECTION (Physical)
0x09, 0x30
;
USAGE (X)
0x09, 0x31
;
USAGE (Y)
0x15, 0x00
;
LOGICAL_MINIMUM (0)
0x26, 0xFF, 0x00
;
LOGICAL_MAXIMUM (255)
0x75, 0x08
;
REPORT_SIZE (8)
0x95, 0x02
;
REPORT_COUNT (2)
0x81, 0x02
;
0xC0
;
END_COLLECTION
INPUT (Data,Var,Abs)
0x05, 0x09
;
USAGE_PAGE (Button)
0x19, 0x01
;
USAGE_MINIMUM (Button 1)
0x29, 0x06
;
USAGE_MAXIMUM (Button 6)
0x15, 0x00
;
LOGICAL_MINIMUM (0)
0x25, 0x01
;
LOGICAL_MAXIMUM (1)
0x75, 0x01
;
REPORT_SIZE (1)
0x95, 0x06
;
REPORT_COUNT (6)
0x81, 0x02
;
INPUT (Data,Var,Abs)
0x95, 0x02
;
REPORT_COUNT (2)
0x81, 0x03
;
INPUT (Constant,Var,Abs)
0xC5
;END_COLLECTION
2004 Microchip Technology Inc.
DS91054C-page 3
TB054
THOUGHT PROCESS FOR DEVELOPING
THIS DESCRIPTOR
The following is the thought process for developing this
descriptor. Please refer to the “HID Usage Tables” for a
complete list of Usage Pages and Usages. (See
“References” at the end of this Technical Brief).
The first thing to do is tell the host that the device is a
game pad. To do this, it is necessary to declare
"USAGE (Game pad)" or "0x09, 0x05" numerically. But,
before doing this, the appropriate page that “Game
pad” is listed on as a Usage must be referenced. Looking game pad up in the HID Usage Tables reveals that
the appropriate Usage Page is Generic Desktop. Once
this Usage Page is declared, Usage Game Pad is
specified. When the host has this information, it knows
to add this device to the game controller category of its
device listing. As a result, the game pad can be calibrated using the game controller calibration program
provided with the host's operating system.
All report descriptors must have an Applications Collection. This Collection specifies the sources of I/O for the
device and the format that the I/O is reported to the
host. The Usage item that follows the Applications Collection specifies the general function of the collection.
In this case, the Usage that follows is Pointer. Pointer
is a Usage on the Generic Desktop Usage Page. It is
not necessary to specify the Generic Desktop Usage
Page again.
Note:
The Usage Page must be specified only if
the Usage that follows is not on the
existing Usage Page.
The D-pad on the game pad controls two axis, X and Y.
Because each axis has the same characteristics in
terms of data report format, these axes can be grouped
into a Collection. The X-axis and Y-axis are physical
parameters; therefore, the Collection is of type
Physical.
The game pad has six buttons. A Physical Collection
could be made and all the buttons listed as Usages
(i.e., Usage {Button 1}, Usage {Button 2}, etc.) similar
to what was done with the X and Y-axis. However, an
easier way to make a list of buttons is to use the Usage
Minimum and Usage Maximum items on the Buttons
Usage Page. Each button accounts for a logical bit as
reflected by the:
• Logical Minimum,
• Logical Maximum, and
• Report Size
The Report Count is six, corresponding to the number
of buttons. These six bits are then input as data with the
input item. Data sent over the USB bus must be sent as
blocks of whole bytes. The six button report bits are two
bits short of a byte. Therefore, a Report Count of two is
specified and these bits are input as constants with the
input item. The entire Application Collection is closed
with the End Collection item.
Implementation
HARDWARE
The specific game pad used in this Technical Brief is
the Dexxa™ eight-button (six actual as seen by the
host) game pad. This game pad connects to the standard game port on a PC. A PC game port has four pins
designated for analog inputs and four pins for digital
inputs. Each axis of the D-pad uses an analog pin to
send its position to the host. The remaining analog and
digital pins are utilized by the six game pad buttons.
Although two of the buttons are connected to analog
pins their inputs are digital, either high or low. The
following circuit diagram shows how the PICmicro is
wired as a translator between the game port and PC.
After the Collection is initialized, Usages X and Y are
declared. Each axis of the D-pad is connected to a
potentiometer inside the game pad. When the D-pad is
pressed, the potentiometer varies the voltage on a wire
connected to one of the A-to-D ports on the
PIC16C765. Therefore, the PICmicro will see a digital
value coming from each axis in the range of 0 to 255.
The Logical Minimum and Logical Maximum correspond to this range. Eight bits are needed to report values in this range, the Report Size reflects this number.
Two reports are needed, one for the X-axis and one for
the Y-axis. The Report Count reflects this number.
These two bytes are then designated as data inputs to
the host with Input (Data, Variable, Absolute). Finally,
the Collection is closed with the item End Collection.
DS91054C-page 4
2004 Microchip Technology Inc.
TB054
USB GAME PAD CIRCUIT DIAGRAM(1)
FIGURE 1:
R2
100Ω
GAME PAD
Button F
2
A
Button E
3
B
Y-axis
4
C
X-axis
5
D
Button A
19
E
Button B
20
F
Button C
21
G
Button D
C1(2)
PIC16C765
22
H
11,32
RA0
6 MHz C2(2)
XTAL
RA1
RA2
RA3
VDD
C4
RD0
RD1
RD2
RD3
VDD
VSS
USB Cable
0.1 µF
To Host
D+
DR1
1.5 kΩ
VUSB
R4 1 k Ω
C5
0.1 µF
C6
0.1 µF
C7
0.1 µF
C13
0.1 µF
C14
0.1 µF
C15
0.1 µF
C21
0.1 µF
C22
0.1 µF
VSS
Note 1:
2:
VDD
C3
A
200 nF
VSS
B
C
D
E
F
G
H
R5 51 kΩ
VSS
Microchip’s PICDEM™ USB board was used to develop the USB game pad. This board has all the external circuitry
necessary in place.
C1 and C2 values selected according to crystal load capacitance.
From Figure 1 it can be seen that the analog pins have
several external components added between the game
pad and PICmicro, namely two resistors and one
capacitor per pin. The reason for this circuitry stems
from the way analog pins were originally read by the
PC. The PC would clear a capacitor tied to ground at its
end and then time how long it took the capacitor to
charge up. The capacitor would charge at a rate proportional to the resistance varied by one axis of the
joystick, for instance. This is legacy technology and is
not needed when using a PICmicro with an analog-todigital converter. As a result, the before-mentioned
circuitry was put into place in order to obtain a clean
analog output from the D-pad. This circuitry is not
needed for buttons E and F since they are digital, but
was put in place so that this diagram will support other
game pads.
2004 Microchip Technology Inc.
SOFTWARE
Microchip's USB support firmware provided a foundation for creating the USB game pad firmware. The firmware provides a linkable file named ch9_usb.asm,
which includes most of the functions described in
Chapter 9 of the USB Specification, v1.1. Also included
with this firmware is the file hidclass.asm. This file
implements functions described in the “HID Device
Class Definitions”. These two files were linked without
any changes to the USB game pad project. The two
remaining assembly files included with the Chapter 9
USB firmware, descript.asm and main.asm, were
altered to implement the game pad conversion.
The USB support firmware has a cursor demonstration
incorporated into it. The file descript.asm contains
the descriptors necessary for the demonstration to
enumerate properly. To convert this file for the game
pad application, the cursor demonstration descriptors
were removed and replaced with the game pad
descriptors. Main.asm was rewritten to contain the
main routine for the game pad conversion. The main
program flow is shown in Figure 2.
DS91054C-page 5
TB054
FIGURE 2:
MAIN ROUTINE BLOCK DIAGRAM
Initialize USB
Read Buttons
Yes
Set CHANGED
Button Change?
No
Read Y-Axis
Yes
Set CHANGED
Y- AxisChange?
No
Read X-Axis
X- AxisChange?
Yes
Set CHANGED
No
No
CHANGED = ?
Yes
Send USB Data
Clear CHANGED
DS91054C-page 6
2004 Microchip Technology Inc.
TB054
CONCLUSION
REFERENCES
For engineers just introduced to USB, descriptors pose
a hurdle that is time-consuming to overcome. Walking
through the conversion of the game pad from the game
port interface to USB is a very effective way of
overcoming this hurdle. Although most of the
PIC16C765's resources are unused for the USB game
pad, this Technical Brief serves as a starting place for
developing more complex USB peripherals using the
PIC16C745 or PIC16C765.
1.
MEMORY USAGE
In the PIC16C765, the following memory was used:
Data Memory:
50 bytes
Program Memory:
1.9 Kbytes
2.
3.
4.
5.
6.
7.
8.
9.
2004 Microchip Technology Inc.
USB Specification, Version 1.1: Chapter 9
(located at www.usb.org)
Device Class Definition for Human Interface
Devices (located at www.usb.org)
HID Usage Tables (located at www.usb.org)
USB Firmware User's Guide (located in
USB Support Firmware zip file at
www.microchip.com)
USB Complete, Second Edition, Jan Axelson;
Lakeview Research, 2001 (www.lvr.com)
TB055: PS/2® to USB Mouse Translator
TB056: Demonstrating the Set_Report Request
with a PS/2® to USB Keyboard Translator
Example
TB057: USB Combination Devices
Demonstrated by a Combination Mouse and
Game Pad Device
TB058: Demonstrating the Soft Detach Function
with a PS/2® to USB Translator Example
DS91054C-page 7
TB054
APPENDIX A:
SOURCE CODE
Due to the length of the source code for the Game Port
to USB Game Pad Translator example, the source
code is available separately. The complete source
code is available as a single WinZip archive file,
tb054sc.zip, which may be downloaded from the
Microchip corporate Web site at www.microchip.com.
DS91054C-page 8
2004 Microchip Technology Inc.
Note the following details of the code protection feature on Microchip devices:
•
Microchip products meet the specification contained in their particular Microchip Data Sheet.
•
Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
•
There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
•
Microchip is willing to work with the customer who is concerned about the integrity of their code.
•
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device
applications and the like is intended through suggestion only
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
No representation or warranty is given and no liability is
assumed by Microchip Technology Incorporated with respect
to the accuracy or use of such information, or infringement of
patents or other intellectual property rights arising from such
use or otherwise. Use of Microchip’s products as critical
components in life support systems is not authorized except
with express written approval by Microchip. No licenses are
conveyed, implicitly or otherwise, under any intellectual
property rights.
Trademarks
The Microchip name and logo, the Microchip logo, Accuron,
dsPIC, KEELOQ, MPLAB, PIC, PICmicro, PICSTART,
PRO MATE, PowerSmart and rfPIC are registered
trademarks of Microchip Technology Incorporated in the
U.S.A. and other countries.
AmpLab, FilterLab, microID, MXDEV, MXLAB, PICMASTER,
SEEVAL, SmartShunt and The Embedded Control Solutions
Company are registered trademarks of Microchip Technology
Incorporated in the U.S.A.
Application Maestro, dsPICDEM, dsPICDEM.net,
dsPICworks, ECAN, ECONOMONITOR, FanSense,
FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP,
ICEPIC, Migratable Memory, MPASM, MPLIB, MPLINK,
MPSIM, PICkit, PICDEM, PICDEM.net, PICtail, PowerCal,
PowerInfo, PowerMate, PowerTool, rfLAB, Select Mode,
SmartSensor, SmartTel and Total Endurance are trademarks
of Microchip Technology Incorporated in the U.S.A. and other
countries.
SQTP is a service mark of Microchip Technology Incorporated
in the U.S.A.
All other trademarks mentioned herein are property of their
respective companies.
© 2004, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
Microchip received ISO/TS-16949:2002 quality system certification for
its worldwide headquarters, design and wafer fabrication facilities in
Chandler and Tempe, Arizona and Mountain View, California in
October 2003. The Company’s quality system processes and
procedures are for its PICmicro® 8-bit MCUs, KEELOQ® code hopping
devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchip’s quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.
2004 Microchip Technology Inc.
DS91054C-page 9
WORLDWIDE SALES AND SERVICE
AMERICAS
China - Beijing
Korea
Corporate Office
Unit 706B
Wan Tai Bei Hai Bldg.
No. 6 Chaoyangmen Bei Str.
Beijing, 100027, China
Tel: 86-10-85282100
Fax: 86-10-85282104
168-1, Youngbo Bldg. 3 Floor
Samsung-Dong, Kangnam-Ku
Seoul, Korea 135-882
Tel: 82-2-554-7200 Fax: 82-2-558-5932 or
82-2-558-5934
China - Chengdu
200 Middle Road
#07-02 Prime Centre
Singapore, 188980
Tel: 65-6334-8870 Fax: 65-6334-8850
2355 West Chandler Blvd.
Chandler, AZ 85224-6199
Tel: 480-792-7200
Fax: 480-792-7277
Technical Support: 480-792-7627
Web Address: http://www.microchip.com
3780 Mansell Road, Suite 130
Alpharetta, GA 30022
Tel: 770-640-0034
Fax: 770-640-0307
Rm. 2401-2402, 24th Floor,
Ming Xing Financial Tower
No. 88 TIDU Street
Chengdu 610016, China
Tel: 86-28-86766200
Fax: 86-28-86766599
Boston
China - Fuzhou
2 Lan Drive, Suite 120
Westford, MA 01886
Tel: 978-692-3848
Fax: 978-692-3821
Unit 28F, World Trade Plaza
No. 71 Wusi Road
Fuzhou 350001, China
Tel: 86-591-7503506
Fax: 86-591-7503521
Atlanta
Chicago
333 Pierce Road, Suite 180
Itasca, IL 60143
Tel: 630-285-0071
Fax: 630-285-0075
Dallas
4570 Westgrove Drive, Suite 160
Addison, TX 75001
Tel: 972-818-7423
Fax: 972-818-2924
Detroit
Tri-Atria Office Building
32255 Northwestern Highway, Suite 190
Farmington Hills, MI 48334
Tel: 248-538-2250
Fax: 248-538-2260
Kokomo
2767 S. Albright Road
Kokomo, IN 46902
Tel: 765-864-8360
Fax: 765-864-8387
Los Angeles
18201 Von Karman, Suite 1090
Irvine, CA 92612
Tel: 949-263-1888
Fax: 949-263-1338
San Jose
1300 Terra Bella Avenue
Mountain View, CA 94043
Tel: 650-215-1444
Fax: 650-961-0286
Toronto
6285 Northam Drive, Suite 108
Mississauga, Ontario L4V 1X5, Canada
Tel: 905-673-0699
Fax: 905-673-6509
ASIA/PACIFIC
Australia
Suite 22, 41 Rawson Street
Epping 2121, NSW
Australia
Tel: 61-2-9868-6733
Fax: 61-2-9868-6755
China - Hong Kong SAR
Unit 901-6, Tower 2, Metroplaza
223 Hing Fong Road
Kwai Fong, N.T., Hong Kong
Tel: 852-2401-1200
Fax: 852-2401-3431
Singapore
Taiwan
Kaohsiung Branch
30F - 1 No. 8
Min Chuan 2nd Road
Kaohsiung 806, Taiwan
Tel: 886-7-536-4818
Fax: 886-7-536-4803
Taiwan
Taiwan Branch
11F-3, No. 207
Tung Hua North Road
Taipei, 105, Taiwan
Tel: 886-2-2717-7175 Fax: 886-2-2545-0139
EUROPE
China - Shanghai
Austria
Room 701, Bldg. B
Far East International Plaza
No. 317 Xian Xia Road
Shanghai, 200051
Tel: 86-21-6275-5700
Fax: 86-21-6275-5060
Durisolstrasse 2
A-4600 Wels
Austria
Tel: 43-7242-2244-399
Fax: 43-7242-2244-393
Denmark
China - Shenzhen
Regus Business Centre
Lautrup hoj 1-3
Ballerup DK-2750 Denmark
Tel: 45-4420-9895 Fax: 45-4420-9910
Rm. 1812, 18/F, Building A, United Plaza
No. 5022 Binhe Road, Futian District
Shenzhen 518033, China
Tel: 86-755-82901380
Fax: 86-755-8295-1393
China - Shunde
Room 401, Hongjian Building, No. 2
Fengxiangnan Road, Ronggui Town, Shunde
District, Foshan City, Guangdong 528303, China
Tel: 86-757-28395507 Fax: 86-757-28395571
China - Qingdao
Rm. B505A, Fullhope Plaza,
No. 12 Hong Kong Central Rd.
Qingdao 266071, China
Tel: 86-532-5027355 Fax: 86-532-5027205
India
Divyasree Chambers
1 Floor, Wing A (A3/A4)
No. 11, O’Shaugnessey Road
Bangalore, 560 025, India
Tel: 91-80-22290061 Fax: 91-80-22290062
Japan
Benex S-1 6F
3-18-20, Shinyokohama
Kohoku-Ku, Yokohama-shi
Kanagawa, 222-0033, Japan
Tel: 81-45-471- 6166 Fax: 81-45-471-6122
France
Parc d’Activite du Moulin de Massy
43 Rue du Saule Trapu
Batiment A - ler Etage
91300 Massy, France
Tel: 33-1-69-53-63-20
Fax: 33-1-69-30-90-79
Germany
Steinheilstrasse 10
D-85737 Ismaning, Germany
Tel: 49-89-627-144-0
Fax: 49-89-627-144-44
Italy
Via Quasimodo, 12
20025 Legnano (MI)
Milan, Italy
Tel: 39-0331-742611
Fax: 39-0331-466781
Netherlands
P. A. De Biesbosch 14
NL-5152 SC Drunen, Netherlands
Tel: 31-416-690399
Fax: 31-416-690340
United Kingdom
505 Eskdale Road
Winnersh Triangle
Wokingham
Berkshire, England RG41 5TU
Tel: 44-118-921-5869
Fax: 44-118-921-5820
02/17/04
DS91054C-page 10
2004 Microchip Technology Inc.