Future Technology Devices International Ltd.

Application Note AN_120

Aliasing VCP Baud Rates
Document Reference No.: FT_000161
Version 1.2
Issue Date: 2016-06-03

The purpose of this document is to provide instruction on how the VCP driver calculates the baud rateused by FTDI devices in UART mode and how non-standard baud rates may be implemented.

Future Technology Devices International Limited (FTDI)
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 (Support): Support1.support@ftdichip.com Web: http://www.ftdichip.com

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Document Reference No.: FT_000161
Aliasing Vcp Baud Rates Application Note AN_120
Version 1.2
Clearance No.: FTDI# 122

Table of Contents
1

Introduction .................................................................... 2

2

Setting the Baud Rate ..................................................... 3

3

Baud Rate Calculation ..................................................... 4

4

Aliasing Baud Rates ........................................................ 5
4.1

Aliasing ..................................................................................... 5

4.2

Aliasing Using the Original Sub-Integer Divisors ...................... 6

4.3

Aliasing Using the Additional Sub-Integer Divisors ................... 8

4.4 Aliasing the FT232H, FT2232H and FT4232H for Baud Rates up
to 12MBaud ..................................................................................... 10

5

Contact Information ...................................................... 12

Appendix A – FTDIPORT.INF Example ................................ 13
Appendix B – Revision History ........................................... 16

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Document Reference No.: FT_000161
Aliasing Vcp Baud Rates Application Note AN_120
Version 1.2
Clearance No.: FTDI# 122

1

Introduction

One of the most basic operations with the FT232H, (UART mode), FT2232H (UART mode), FT4232H(UART mode), FT232R, FT2232D (UART mode), FT232B, FT230X, FT231X and FT234X devices is setting a
Baud rate. This application note describes the various ways that this can be done. It also describes how
to use non-standard baud rates with FTDI's USB-Serial IC devices, including a technique called 'aliasing' where one Baud rate is substituted by the driver in place of another baud rate.
The second generation FT232B USB UART IC added additional granularity to the divisor used to generate
the device Baud rate. This allows a much larger number of baud rates to be used with the FT232B andsubsequent devices when compared to its predecessor, the FT8U232AM.

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Document Reference No.: FT_000161
Aliasing Vcp Baud Rates Application Note AN_120
Version 1.2
Clearance No.: FTDI# 122

2

Setting the Baud Rate

When using FTDI Virtual COM Port (VCP) drivers, the Baud rate can be set in the Device Manager or froman application. When the Baud rate is set from an application program it is done in exactly the same way
as with a standard legacy Windows COM Port - by simply passing the required Baud rate to the port using
the Windows VCOMM API calls or a COM Port library. Both standard and non-standard baud rates can be
set in this manner.
When using FTDI's D2XX direct driver the function FT_SetBaudRate can be used to set both standard andnon-standard baud rates. See the D2XX Programmer's Guide for further details on using
FT_SetBaudeRate.
If a non-standard Baud rate is required, the formulae in this application note can be used to determine if
it is possible.
If the required non-standard Baud rate is possible simply pass it to the driver as normal and the required
divisor will be calculated by the driver. For D2XX there is no longer any need to use the function
FT_SetDivisor, but it has been left in for backward compatibility.

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Version 1.2
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3

Baud Rate Calculation

A Baud rate for the FT230X, FT231X, FT234X ,FT232R, FT2232D (UART mode) or FT232B is generatedusing the chips internal 48MHz clock. This is input to the Baud rate generator circuitry where it is thendivided by 16 and fed into a prescaler as a 3MHz reference clock. This 3MHz reference clock is thendivided down to provide the required Baud rate for the device's on chip UART. The value of the Baud rate
divisor is an integer plus a sub-integer prescaler.
This is also true for the FT232H, FT2232H (UART mode) and FT4232H (UART mode) up to 3MBaud. For
higher baud rates the reference clock is an internal 12MHz clock and will be discussed later in the
document.
The original FT8U232AM only allowed 3 sub-integer prescalers - 0.125, 0.25 or 0.5.
The FT2232H (UART mode), FT4232H (UART mode), FT230X, FT231X, FT234X FT232R, FT2232D (UART
mode) and FT232B support a further 4 additional sub-integer prescalers - 0.375, 0.625, 0.75, and 0.875.
Thus, allowed values for the Baud rate divisor are:Divisor = n + 0, 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, 0.875;
where n is an integer between 2 and 16384 (214).
Note: Divisor = 1 and Divisor = 0 are special cases. A divisor of 0 will give 3 MBaud, and adivisor of 1 will give 2 MBaud. Sub-integer divisors are not allowed if the main divisor (n) iseither 0 or 1.
Therefore the value of the divisor needed for a given Baud rate is found by dividing 3000000 by therequired Baud rate.
The exact Baud rate may not be achievable - however as long as the actual Baud rate used is within +/3% of the required Baud rate, then the link should function without errors. When a Baud rate is passed tothe driver where the exact divisor required is not achievable the closest possible Baud rate divisor will be
used as long as that divisor gives a Baud rate which is within +/- 3% of the Baud rate originally set.
For example:
A non-standard Baud rate of 490000 Baud is required.
Required divisor = 3000000 / 490000 = 6.122
The closest achievable divisor is 6.125, which gives a baud rate of 489795.9, which is well within theallowed +/- 3% margin of error. Therefore 490000 can be passed to the driver and the device willcommunicate without errors.

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Document Reference No.: FT_000161
Aliasing Vcp Baud Rates Application Note AN_120
Version 1.2
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4

Aliasing Baud Rates

4.1 Aliasing
The file FTDIPORT.INF contains entries that are used as the divisors for standard Baud rates. By changing
these it is possible to alias standard Baud rates with non-standard values - for instance replacing
115kBaud with 512kBaud. Users would then set up the devices to operate at 512kBaud by selecting
115kBaud for the appropriate serial port.

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Aliasing Vcp Baud Rates Application Note AN_120
Version 1.2
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4.2 Aliasing Using the Original Sub-Integer Divisors
The FtdiPort.NT.HW.AddReg section of FTDIPORT.INF contains the ConfigData string and it is this stringthat controls the baud rate calculation.
The FTDIPORT.inf file may be viewed and edited with any text editor e.g. WordPad or Notepad[FtdiPort.NT.HW.AddReg]
HKR,,ConfigData,1,01,00,3F,3F,10,27,88,13,C4,09,E2,04,71,02,38,41,9c,80,4E,C0,34,00,1A,00,0D,00,0
6,40,03,80,00,00,d0,80
Each field consists of a pair of bytes, ordered as follows: Byte0, Byte1. Bits 13 through 0 denote theinteger divisor while bits 16, 15 and 14 denote the sub-integer divisor, as follows
15,14 = 00 - sub-integer divisor = 0
15,14 = 01 - sub-integer divisor = 0.5
15,14 = 10 - sub-integer divisor = 0.25
15,14 = 11 - sub-integer divisor = 0.125
The divisor can be extracted for each entry in a few simple steps, as shown here for the entry 9c,80
Step 1 - re-order the bytes: 9c,80 => 809c Hex
Step 2 - extract the sub-integer divisor; 15 = 1, 14 = 0 => sub-integer = 0.25
Step 3 - extract the integer divisor: 13:0 = 009c Hex = 156 Dec
Step 4 - combine the integer and sub-integer divisors: 156.25 Dec
Step 5 - divide 3000000 by the divisor=> 3000000/156.25 = 19,200 baud
The following lists the standard values and their respective baud rates
10,27 => divisor = 10000, rate = 300
88,13 => divisor = 5000, rate = 600
C4,09 => divisor = 2500, rate = 1,200
E2,04 => divisor = 1250, rate = 2,400
71,02 => divisor = 625, rate = 4,800
38,41 => divisor = 312.5, rate = 9,600
9C,80 => divisor = 156.25, rate = 19,200
4E,C0 => divisor = 78.125, rate = 38,400
34,00 => divisor = 52, rate = 57,692
1A,00 => divisor = 26, rate = 115,384
0D,00 => divisor = 13, rate = 230,769
06,40 => divisor = 6.5, rate = 461,538
03,80 => divisor = 3.25, rate = 923,076
00,00 => RESERVED
D0,80 => divisor = 208.25, rate = 14,406
To alias a baud rate of 920k baud to the standard 56k baud menu option under windows:- change the 34,00 entry to 03,80 (simple as both of the values are available from the previous list)
To alias a rate of 197k baud to the standard 4,800 baud menu option under windows:- find the best divisor, check that it is sufficiently accurate and then modify the appropriate INF file
entry.
3,000,000/197,000 = 15.228. The best divisor is 15.25.
3,000,000/15.25 = 196,721.
196,721/197,000 = 99.8%.
This is well within the required 3% tolerance.
Set bit 15:14 to 10 for a sub-integer divisor of 0.25, and the lower bits to 0F.

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Document Reference No.: FT_000161
Aliasing Vcp Baud Rates Application Note AN_120
Version 1.2
Clearance No.: FTDI# 122- replace the 71,02 entry with 0F,80.
Incorporating these two changes the FTDIPORT.INF entry becomes[FtdiPort.NT.HW.AddReg]
HKR,,ConfigData,1,01,00,3F,3F,10,27,88,13,C4,09,E2,04,0F,80,38,41,9C,80,4E,C0,03,80,1A,00,0
D,00,06,40,03,80,00,00,00,00

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Document Reference No.: FT_000161
Aliasing Vcp Baud Rates Application Note AN_120
Version 1.2
Clearance No.: FTDI# 122

4.3 Aliasing Using the Additional Sub-Integer Divisors
The standard FTDIPORT.INF ConfigData Baud rate table only supports the original FT8U232AM
sub-integer prescalers and not the new ones added for the FT232B and subsequent devices. To allow theaddition sub- integer prescalers to be used when aliasing a Baud rate the following ConfigData entry isneeded:[FtdiPort.NT.HW.AddReg]
HKR,,ConfigData,1,11,00,3F,3F,10,27,00,00,88,13,00,00,C4,09,00,00,E2,04,00,00,71,02,00,00,38,
41,00,00,9C,80,00,00,4E,C0,00,00,34,00,00,00,1A,00,00,00,0D,00,00,00,06,40,00,00,03,80,00,00,
00,00,00,00,D0,80,00,00(Note - The current ftdiport.inf file contains both formats for the config data string. You select/disable thecorrect string by using a ; at the start of the line to comment out the one you do not want. Only one
entry for Config Data should be used.)In this case each field consists of 4 bytes, ordered as follows: Byte0, Byte1, Byte2, Byte3. Bits 13
through 0 denote the integer divisor while bits 16, 15 and 14 denote the sub-integer divisor, as
follows:
16,15,14 = 000 - sub-integer divisor = 0
16,15,14 = 001 - sub-integer divisor = 0.5
16,15,14 = 010 - sub-integer divisor = 0.25
16,15,14 = 011 - sub-integer divisor = 0.125
16,15,14 = 100 - sub-integer divisor = 0.375
16,15,14 = 101 - sub-integer divisor = 0.625
16,15,14 = 110 - sub-integer divisor = 0.75
16,15,14 = 111 - sub-integer divisor = 0.875
Note that this ConfigData entry is the same as before except that each field consists of 4 bytes
instead of 2 bytes. The first highlighted byte in ConfigData is the Flags byte and format of the fields
is determined by Bit4 of the Flags byte. In the example above, setting Flags byte to 11 means that
Bit4 is set and 4 byte fields are being used.
The divisor can be extracted for each entry in a few simple steps, as shown here for the entry
35,40,01,00
Step 1 - re-order the bytes: 35,40,01,00 => 00014035 Hex
Step 2 - extract the sub-integer divisor; 16 = 1, 15 = 0, 14 = 1 => sub-integer = 0.625
Step 3 - extract the integer divisor: 13:0 = 0035 Hex = 53 Dec
Step 4 - combine the integer and sub-integer divisors: 53.625 Dec
Step 5 - divide 3000000 by the divisor => 3000000/53.625 = 55944 baud
The following lists the standard values and their respective baud rates.
10,27,00,00 => divisor = 10000, rate = 300
88,13,00,00 => divisor = 5000, rate = 600
C4,09,00,00 => divisor = 2500, rate = 1,200
E2,04,00,00 => divisor = 1250, rate = 2,400
71,02,00,00 => divisor = 625, rate = 4,800
38,41,00,00 => divisor = 312.5, rate = 9,600
9C,80,00,00 => divisor = 156.25, rate = 19,200
4E,C0,00,00 => divisor = 78.125, rate = 38,400
34,00,00,00 => divisor = 52, rate = 57,692
1A,00,00,00 => divisor = 26, rate = 115,384
0D,00,00,00 => divisor = 13, rate = 230,769
06,40,00,00 => divisor = 6.5, rate = 461,538
03,80,00,00 => divisor = 3.25, rate = 923,076
00,00,00,00 => RESERVED
D0,80,00,00 => divisor = 208.25, rate = 14,406
To alias a rate of 920k baud to the standard 56k baud menu option under windows:

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Document Reference No.: FT_000161
Aliasing Vcp Baud Rates Application Note AN_120
Version 1.2
Clearance No.: FTDI# 122- change the 34,00,00,00 entry to 03,80,00,00 (simple as both of the values are available from theprevious list)
To alias a rate of 197k baud to the standard 4,800 baud menu option under windows:- find the best divisor, check that it is sufficiently accurate and then modify the appropriate INF file
entry.
3000000/197,000 = 15.228. The best divisor is 15.25.
3000000/15.25 = 196,721.
196,721/197,000 = 99.8%.
This is well within the required 3% tolerance.
Set bits 16:15:14 to 010 for a sub-integer divisor of 0.25, and the lower bits to 0F.
- replace the 71,02,00,00 entry with 0F,80,00,00.
Incorporating these two changes the FTDIPORT.INF entry becomes
FtdiPort.NT.HW.AddReg]
HKR,,ConfigData,1,11,00,3F,3F,10,27,00,00,88,13,00,00,C4,09,00,00,E2,04,00,00,0F,80,00,00,38,41,00,00,9C,80,00,00,4E,C0,00,00,03,80,00,00,1A,00,00,00,0D,00,00,00,06,40,00,00,03,80,00,00,00,00,00,00,D0,80,00,00

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4.4 Aliasing the FT232H, FT2232H and FT4232H for Baud Rates up to
12MBaud
The instructions in section 4.3 are still applicable for the FT232H, FT2232H and the FT4232H up to
3MBaud.
The calculations for sub integers still apply.
To alias baud rates between 3MBaud and 12MBaud it is necessary to use driver version 2.4.20 or laterand the most significant bit (MSB) of the divisor must be a 1. This will ensure the divisor is dividing a
12MHz clock and not a 3MHz clock.
Example:Each field consists of 4 bytes, ordered as follows: Byte0, Byte1, Byte2, Byte3. Bits 13
through 0 denote the integer divisor while bits 16, 15 and 14 denote the sub-integer divisor, as
follows
16,15,14 = 000 - sub-integer divisor = 0
16,15,14 = 001 - sub-integer divisor = 0.5
16,15,14 = 010 - sub-integer divisor = 0.25
16,15,14 = 011 - sub-integer divisor = 0.125
16,15,14 = 100 - sub-integer divisor = 0.375
16,15,14 = 101 - sub-integer divisor = 0.625
16,15,14 = 110 - sub-integer divisor = 0.75
16,15,14 = 111 - sub-integer divisor = 0.875
The following lists the standard values and their respective baud rates.
10,27,00,80 => divisor = 10000, rate = 1,200
88,13,00,80 => divisor = 5000, rate = 2,400
C4,09,00,80 => divisor = 2500, rate = 4,800
E2,04,00,80 => divisor = 1250, rate = 9,600
71,02,00,80 => divisor = 625, rate = 19,200
38,41,00,80 => divisor = 312.5, rate = 38,400
9C,80,00,80 => divisor = 156, rate = 76,923
4E,C0,00,80 => divisor = 78, rate = 153,846
34,00,00,80 => divisor = 52, rate = 230,769
1A,00,00,80 => divisor = 26, rate = 461,538
0D,00,00,80 => divisor = 13, rate = 923,077
06,40,00,80 => divisor = 6.5, rate = 1,846,153
03,80,00,80 => divisor = 3.25, rate = 3,692,308
00,00,00,80 => RESERVED
D0,80,00,80 => divisor = 208.25, rate = 57,623
Note: Divisor = 1 and Divisor = 0 are special cases. A divisor of 0 will give 12MBaud, and adivisor of 1 will give 8MBaud. Sub-integer divisors are not allowed if the main divisor (n) iseither 0 or 1.
To alias a rate of 38400 baud to the standard 300 baud menu option under windows:- change the 10,27,00,00 entry to 38,41,00,80 (simple as both of the values are available from theprevious list)
To alias a rate of 5.5M baud to the standard 19200 baud menu option under windows:- find the best divisor, check that it is sufficiently accurate and then modify the appropriate INF file
entry.
12000000/5,500,000 = 2.1818. The best divisor is 2.125.
12000000/2.125 = 5,647,000 (approx).
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5,647,000/8,5000,000 = 102.67%.
This is just within the required 3% tolerance.
Set bits 16:15:14 to 011 for a sub-integer divisor of 0.125, and the lower bits to 10.
MSB must be a 1 as the master clock is 12MHzThis gives 0 1100 0000 0000 0010. This gives the 4 bytes as 80 00 C0 02.
These are re-arranged as 02,C0,00,80- replace the 71,02,00,00 entry for the 19200 baud with 02,C0,00,80.
Incorporating these two changes the FTDIPORT.INF entry becomes
FtdiPort.NT.HW.AddReg]
HKR,,ConfigData,1,11,00,3F,3F,10,27,00,00,88,13,00,00,C4,09,00,00,E2,04,00,00,02,C0,00,80,38,41,00,00,9C,80,00,00,4E,C0,00,00,03,80,00,00,1A,00,00,00,0D,00,00,00,06,40,00,00,03,80,00,00,00,00,00,00,D0,80,00,00

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5

Contact Information

Head Office – Glasgow, UK

Branch Office – Tigard, Oregon, USA

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

Future Technology Devices International Limited(USA)
7130 SW Fir Loop
Tigard, OR 97223-8160
USA
Tel: +1 (503) 547 0988
Fax: +1 (503) 547 0987

E-mail (Sales)
E-mail (Support)
E-mail (General
Enquiries)

E-mail (Sales)
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E-mail (General
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sales1@ftdichip.com
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admin1@ftdichip.com

us.sales@ftdichip.com
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us.admin@ftdichip.com

Branch Office – Taipei, Taiwan

Branch Office – Shanghai, China

Future Technology Devices International Limited(Taiwan)
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Taiwan , R.O.C.
Tel: +886 (0) 2 8797 1330
Fax: +886 (0) 2 8751 9737

Future Technology Devices International Limited(China)Room 1103, No. 666 West Huaihai Road,
Shanghai, 200052
China
Tel: +86 21 62351596
Fax: +86 21 62351595

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cn.sales@ftdichip.com
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cn.admin@ftdichip.com

Distributor and Sales Representatives
Please visit the Sales Network page of the FTDI Web site for the contact details of our distributor(s) andsales 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 aresupplied 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. Yourstatutory rights are not affected. This product or any variant of it is not intended for use in any medical appliance, device or system inwhich the failure of the product might reasonably be expected to result in personal injury. This document provides preliminary
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.

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Appendix A – FTDIPORT.INF Example; FTDIPORT.INF;; Copyright © 2000-2016 Future Technology Devices International Limited;; USB serial port driver installation file for Windows 2000, XP, Server 2003, Vista, Server 2008,; Windows 7, Server 2008 R2, Windows 8, Windows 8.1, Server 2012 R2 and Windows 10.
[Version]
Signature="$Windows NT$"
DriverPackageType=PlugAndPlay
DriverPackageDisplayName=%DESC%Class=Ports
ClassGUID={4d36e978-e325-11ce-bfc1-08002be10318}
Provider=%FTDI%
CatalogFile=ftdiport.cat
DriverVer=03/09/2016,2.12.16[SourceDisksNames]
1=%DriversDisk%,,,[SourceDisksFiles]
ftser2k.sys=1,i386
ftserui2.dll=1,i386
ftcserco.dll = 1,i386[SourceDisksFiles.amd64]
ftser2k.sys=1,amd64
ftserui2.dll=1,amd64
ftcserco.dll = 1,amd64[DestinationDirs]
FtdiPort.NT.Copy=10,system32\drivers
FtdiPort.NT.CopyUI=10,system32
FtdiPort.NT.CopyCoInst=10,system32[ControlFlags]
ExcludeFromSelect=*[Manufacturer]%FTDI%=FtdiHw,NTamd64[FtdiHw]%VID_0403&PID_6001.DeviceDesc%=FtdiPort.NT,FTDIBUS\COMPORT&VID_0403&PID_6001%VID_0403&PID_6010.DeviceDesc%=FtdiPort.NT,FTDIBUS\COMPORT&VID_0403&PID_6010%VID_0403&PID_6011.DeviceDesc%=FtdiPort.NT,FTDIBUS\COMPORT&VID_0403&PID_6011%VID_0403&PID_6014.DeviceDesc%=FtdiPort.NT,FTDIBUS\COMPORT&VID_0403&PID_6014%VID_0403&PID_6015.DeviceDesc%=FtdiPort.NT,FTDIBUS\COMPORT&VID_0403&PID_6015%VID_0403&PID_6031.DeviceDesc%=FtdiPort.NT,FTDIBUS\COMPORT&VID_0403&PID_6031%VID_0403&PID_0000.DeviceDesc%=FtdiPort.NT,FTDIBUS\COMPORT&VID_0403&PID_0000[FtdiHw.NTamd64]%VID_0403&PID_6001.DeviceDesc%=FtdiPort.NTamd64,FTDIBUS\COMPORT&VID_0403&PID_6001%VID_0403&PID_6010.DeviceDesc%=FtdiPort.NTamd64,FTDIBUS\COMPORT&VID_0403&PID_6010%VID_0403&PID_6011.DeviceDesc%=FtdiPort.NTamd64,FTDIBUS\COMPORT&VID_0403&PID_6011%VID_0403&PID_6014.DeviceDesc%=FtdiPort.NTamd64,FTDIBUS\COMPORT&VID_0403&PID_6014%VID_0403&PID_6015.DeviceDesc%=FtdiPort.NTamd64,FTDIBUS\COMPORT&VID_0403&PID_6015%VID_0403&PID_6031.DeviceDesc%=FtdiPort.NTamd64,FTDIBUS\COMPORT&VID_0403&PID_6031%VID_0403&PID_0000.DeviceDesc%=FtdiPort.NTamd64,FTDIBUS\COMPORT&VID_0403&PID_0000[FtdiPort.NT.AddService]
DisplayName = %SvcDesc%
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ServiceType = 1 ; SERVICE_KERNEL_DRIVER
StartType= 3 ; SERVICE_DEMAND_START
ErrorControl = 1 ; SERVICE_ERROR_NORMAL
ServiceBinary = %10%\system32\drivers\ftser2k.sys
LoadOrderGroup = Base; -------------- Serenum Driver install section[SerEnum_AddService]
DisplayName = %SerEnum.SvcDesc%
ServiceType = 1 ; SERVICE_KERNEL_DRIVER
StartType= 3 ; SERVICE_DEMAND_START
ErrorControl = 1 ; SERVICE_ERROR_NORMAL
ServiceBinary = %12%\serenum.sys
LoadOrderGroup = PNP Filter[FtdiPort.NT.AddReg]
HKR,,EnumPropPages32,,"ftserui2.dll,SerialPortPropPageProvider"[FtdiPort.NT.Copy]
ftser2k.sys[FtdiPort.NT.CopyUI]
ftserui2.dll[FtdiPort.NT.CopyCoInst]
ftcserco.dll[FtdiPort.NT]
CopyFiles=FtdiPort.NT.Copy,FtdiPort.NT.CopyUI
AddReg=FtdiPort.NT.AddReg[FtdiPort.NTamd64]
CopyFiles=FtdiPort.NT.Copy,FtdiPort.NT.CopyUI
AddReg=FtdiPort.NT.AddReg[FtdiPort.NT.HW]
AddReg=FtdiPort.NT.HW.AddReg[FtdiPort.NTamd64.HW]
AddReg=FtdiPort.NT.HW.AddReg[FtdiPort.NT.Services]
AddService = FTSER2K, 0x00000002, FtdiPort.NT.AddService
AddService = Serenum,,SerEnum_AddService
DelService = FTSERIAL[FtdiPort.NTamd64.Services]
AddService = FTSER2K, 0x00000002, FtdiPort.NT.AddService
AddService = Serenum,,SerEnum_AddService
DelService = FTSERIAL[FtdiPort.NT.HW.AddReg]
HKR,,"UpperFilters",0x00010000,"serenum";HKR,,"ConfigData",1,01,00,3F,3F,10,27,88,13,C4,09,E2,04,71,02,38,41,9c,80,4E,C0,34,00,1A,00,0D,00,06,40,03,80,00,00,d0,80
HKR,,"ConfigData",1,11,00,3F,3F,10,27,00,00,88,13,00,00,C4,09,00,00,E2,04,00,00,71,02,00,00,38,41,
00,00,9C,80,00,00,4E,C0,00,00,34,00,00,00,1A,00,00,00,0D,00,00,00,06,40,00,00,03,80,00,00,00,00,0
0,00,D0,80,00,00
HKR,,"MinReadTimeout",0x00010001,0
HKR,,"MinWriteTimeout",0x00010001,0
Copyright © Future Technology Devices International Limited 14

Document Reference No.: FT_000161
Aliasing Vcp Baud Rates Application Note AN_120
Version 1.2
Clearance No.: FTDI# 122

HKR,,"LatencyTimer",0x00010001,16[FtdiPort.NT.CoInstallers]
AddReg=FtdiPort.NT.CoInstallers.AddReg
CopyFiles=FtdiPort.NT.CopyCoInst[FtdiPort.NTamd64.CoInstallers]
AddReg=FtdiPort.NT.CoInstallers.AddReg
CopyFiles=FtdiPort.NT.CopyCoInst[FtdiPort.NT.CoInstallers.AddReg]
HKR,,CoInstallers32,0x00010000,"ftcserco.Dll,FTCSERCoInstaller";---------------------------------------------------------------;[Strings]
FTDI="FTDI"
DESC="CDM Driver Package - VCP Driver"
DriversDisk="FTDI USB Drivers Disk"
PortsClassName = "Ports (COM & LPT)"
VID_0403&PID_6001.DeviceDesc="USB Serial Port"
VID_0403&PID_6010.DeviceDesc="USB Serial Port"
VID_0403&PID_6011.DeviceDesc="USB Serial Port"
VID_0403&PID_6014.DeviceDesc="USB Serial Port"
VID_0403&PID_6015.DeviceDesc="USB Serial Port"
VID_0403&PID_6031.DeviceDesc="USB Serial Port"
VID_0403&PID_0000.DeviceDesc="USB Serial Port"
SvcDesc="USB Serial Port Driver"
SerEnum.SvcDesc="Serenum Filter Driver"

Copyright © Future Technology Devices International Limited 15

Document Reference No.: FT_000161
Aliasing Vcp Baud Rates Application Note AN_120
Version 1.2
Clearance No.: FTDI# 122

Appendix B – Revision History
Document Title:

AN_120 Aliasing VCP Baud Rates

Document Reference No.:

FT_000161

Clearance No.:

FTDI# 122

Product Page:

http://www.ftdichip.com/FTProducts.htm

Document Feedback:Send Feedback

Revision

ChangesDate

1.0First Release

06/11/2009

1.1

Corrected issues about baud rates between 6Mbaudand 12Mbaud in Ft4232H and Ft2232H

02/11/2010

1.2

Updated errors. Removed copyright year & updated
contact information

25/05/2016

Copyright © Future Technology Devices International Limited 16