AN_137: Vinculum-II IO Cell Description

Document Reference No.: FT_000232
Vinculum-II IO Cell Description Application Note AN_137
Version 1.0
Clearance No.: FTDI# 140
Future Technology Devices International Ltd.
Application Note AN_137
Vinculum-II IO Cell Description
Document Reference No.: FT_000232
Version 1.0
Issue Date: 2010-02-19
The purpose of this document is to describe the IO Cell type used in the Vinculum-II devices interface.
Copyright © 2010 Future Technology Devices International Limited
1
Document Reference No.: FT_000232
Vinculum-II IO Cell Description Application Note AN_137
Version 1.0
Clearance No.: FTDI# 140
TABLE OF CONTENTS
1
Introduction............................................................................................ 3
2
The IO Cell .............................................................................................. 4
3
Summary ................................................................................................ 5
4
Contact Information............................................................................... 6
Appendix A– Revision History .................................................................... 8
Copyright © 2010 Future Technology Devices International Limited
2
Document Reference No.: FT_000232
Vinculum-II IO Cell Description Application Note AN_137
Version 1.0
Clearance No.: FTDI# 140
1
Introduction
The Vinculum VNC2 device is FTDI’s 2nd generation USB host solution device and expands on the
capabilities of the VNC1L. The device is supplied in 6 different packages. There are 32 pin QFN and LQFP
packages, 48 pin QFN and LQFP packages and 64 pin QFN and LQFP packages.
The 32 pin packages have 12 IO pins, the 48 pin package has 28 IO pins and the 64 pin package has 44
IO pins.
Each of the IO pins interface to the external logic and may be defined as an input or an output. All IO
pins default to an input following a reset.
Following a reset, the IO MUX module within VNC2 can be enabled to set pin function and direction. The
actual definition of the pin function and direction is controlled by the firmware.
Copyright © 2010 Future Technology Devices International Limited
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Document Reference No.: FT_000232
Vinculum-II IO Cell Description Application Note AN_137
Version 1.0
Clearance No.: FTDI# 140
2
The IO Cell
The IO cell is an LVTTL 3V3 (5V tolerant IO Cell).
E
I
4-16mA
IO - 3V3 (5V Tol.)
PU
O
PD
Figure 1: IO Cell
LVTTL
Low Voltage Transistor Transistor Logic
E
Enable to enable the output stage
I
Input
O
Output
IO
Input/Output
PU
Pull up resistor (75kOhm) option
PD
Pull down resistor (75kOhm) option
Figure 2: Symbol Table
The IO drive strength of the output stage may be configured to be either 4mA, 8mA, 12mA or 16mA. This
is controlled by a register setting which is set within the firmware. The default is 4mA.
The input may be configured to use a pull up, pull down resistor or have no termination at all.
The value of the pull up / pull down is 75kOhm. The default is to disable the pull up and pull down
resistors.
There is also the capability to control the slew rate – fast or slow. The default is set to fast.
An additional option is the capability of configuring each IO input as a normal input or a Schmitt trigger
input. The default is to disable the Schmitt trigger capability.
Copyright © 2010 Future Technology Devices International Limited
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Document Reference No.: FT_000232
Vinculum-II IO Cell Description Application Note AN_137
Version 1.0
Clearance No.: FTDI# 140
3
Summary
Although designed for use in a 3V3 system, the IO is tolerant of 5V inputs and can be used to interface to
3V3 or 5V systems. With the configurability of the cell it is not necessary to use external pull up or pull
down resistors to realise a design which will result in a smaller bill of materials and less board space on
the PCB.
Copyright © 2010 Future Technology Devices International Limited
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Document Reference No.: FT_000232
Vinculum-II IO Cell Description Application Note AN_137
Version 1.0
Clearance No.: FTDI# 140
4
Contact Information
Head Office – Glasgow, UK
Future Technology Devices International Limited
Unit 1, 2 Seaward Place, Centurion Business Park
Glasgow G41 1HH
United Kingdom
Tel: +44 (0) 141 429 2777
Fax: +44 (0) 141 429 2758
E-mail (Sales) [email protected]
E-mail (Support) [email protected]
E-mail (General Enquiries) [email protected]
Web Site URL http://www.ftdichip.com
Web Shop URL http://www.ftdichip.com
Branch Office – Taipei, Taiwan
Future Technology Devices International Limited (Taiwan)
2F, No 516, Sec. 1 NeiHu Road
Taipei 114
Taiwan, R.O.C.
Tel: +886 (0) 2 8797 1330
Fax: +886 (0) 2 8751 9737
E-mail (Sales)
[email protected]
E-mail (Support)
[email protected]
E-mail (General Enquiries) [email protected]
Web Site URL
http://www.ftdichip.com
Branch Office – Hillsboro, Oregon, USA
Future Technology Devices International Limited (USA)
7235 NW Evergreen Parkway, Suite 600
Hillsboro, OR 97123-5803
USA
Tel: +1 (503) 547 0988
Fax: +1 (503) 547 0987
E-Mail (Sales)
[email protected]
E-Mail (Support) [email protected]
Web Site URL
http://www.ftdichip.com
Branch Office – Shanghai, China
Future Technology Devices International Limited (China)
Room 408, 317 Xianxia Road,
ChangNing District,
ShangHai, China
Tel: +86 (21) 62351596
Fax: +86(21) 62351595
E-Mail (Sales): [email protected]
E-Mail (Support): [email protected]
E-Mail (General Enquiries): [email protected]
Web Site URL: http://www.ftdichip.com
Copyright © 2010 Future Technology Devices International Limited
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Document Reference No.: FT_000232
Vinculum-II IO Cell Description Application Note AN_137
Version 1.0
Clearance No.: FTDI# 140
Distributor and Sales Representatives
Please visit the Sales Network page of the FTDI Web site for the contact details of our distributor(s) and
sales representative(s) in your country.
Neither the whole nor any part of the information contained in, or the product described in this manual, may be adapted or reproduced
in any material or electronic form without the prior written consent of the copyright holder. This product and its documentation are
supplied on an as-is basis and no warranty as to their suitability for any particular purpose is either made or implied. Future Technology
Devices International Ltd will not accept any claim for damages howsoever arising as a result of use or failure of this product. Your
statutory rights are not affected. This product or any variant of it is not intended for use in any medical appliance, device or system in
which the failure of the product might reasonably be expected to result in personal injury. This document provides preliminar y
information that may be subject to change without notice. No freedom to use patents or other intellectual property rights is implied by
the publication of this document. Future Technology Devices International Ltd, Unit 1, 2 Seaward Place, Centurion Business Park,
Glasgow G41 1HH United Kingdom. Scotland Registered Number: SC136640
Copyright © 2010 Future Technology Devices International Limited
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Document Reference No.: FT_000232
Vinculum-II IO Cell Description Application Note AN_137
Version 1.0
Clearance No.: FTDI# 140
Appendix A– Revision History
Version Draft First Draft
Version 1.0
First release
01/02/2010
19/02/2010
Copyright © 2010 Future Technology Devices International Limited
8