Rev. 0.6 3/11

Copyright © 2011 by Silicon Laboratories

AN220

AN220

1. Introduction

The information in this document and the associated

software download is intended for use by developers

creating USB products based on the CP210x USB-to-

UART

Bridge

Controller

device

family

or

the

C8051F32x, C8051F34x, C8051F38x, C8051T32x, and

C8051T62x USB MCU device families A Virtual COM

Port Driver is available for the CP210x family and is

included with the purchase of a CP210x Evaluation Kit.

Additionally,

drivers

can

be

created

using

the

development

kit

for

the

CP210x,

C8051F32x, C8051F34x, C8051F38x, C8051T32x, and

C8051T62x device families. This document describes

driver installation using the Custom USB Driver

Installation Wizard.

2. Customizing Driver Installations

The driver installation is customizable by modifying

certain sections of the hardware installation files (.inf).

The strings contained in the .inf files affect what is

displayed in the “Found New Hardware Wizard” dialogs,

Device Manager, and the Registry. The changes to the

VID and PID in the driver installation should match the

VID and PID contained in the EPROM/FLASH of your

product. See “AN144: CP21xx Device Customization

Guide” for more information on changing the VID and

PID for your product.

Note: Any changes to the Windows installation .inf files will

require new Windows Hardware Quality Labs (WHQL)

tests.

3. Using the Custom USB Driver

Installation Wizard

The Custom USB Driver Installation Wizard generates a

custom driver installation for distribution to end-users.

This customized installation consists of modified .inf

files, optional installation support files, and driver files

for Windows 2000/XP/Server 2003/Vista/Windows 7.

The optional installation executable provided can be

used to copy driver files and register a device on a PC

before or after the device has been connected. It will

also add an entry in the add/remove programs listing.

When the device is connected to the PC for the first

time, the drivers will be installed with little interaction

from the user.

Note: A customized installation does not contain certified

drivers for Windows XP/2003/Vista/7. Certification

must be performed by Microsoft for the new driver

installation. An uncertified installation will not cause

any other problems other than the warning message

displayed by Windows XP/2003/Vista when installing

uncertified drivers. Uncertified drivers cannot be

installed in Windows 7 unless they are installed with a

testing certificate or the Ignore Serial Signing option is

enabled by pressing F8 on startup and selecting the

corresponding option.

To run the Custom USB Driver Installation Wizard, open

CustomUSBDriverWizard.exe, which is included in the

AN220SW.zip download. Figure 1 shows the first

screen of the Custom USB Driver Installation Wizard.

Choose the type of driver installation desired. For

detailed instructions on creating a custom driver

installation, see “4. Creating a Custom Driver”. This

description goes through the process of customizing a

CP210x

driver.

The

process

for

creating

a

USBXpress™ driver is the same as this description,

only select “USBXpress Driver” on the starting screen of

the wizard.

Figure 1. Driver Installation Selection

Relevant Devices

This application note applies to the following devices:

CP2101/2/3/4/5, C8051F320/1/6/7, C8051F340/1/2/3/4/5/6/7/8/9/A/B/C/D, C8051F380/1/2/3/4/5/6/7,

C8051T320/1/2/3/6/7, C8051T620/1/2/3