While the following techniques apply mostly to Win 9x, some of the concepts
(such as the BIOS Settings) may also help resolve issues in Win XP. This info
is offered as a courtesy on an AS IS basis and VTB makes no warranties and
bears no responsibility for issues that may result for your use of this info.
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USB Connectivity Requirements:
To achieve proper USB connectivity six basic system elements must be present
and working correctly.
1) Support from the BIOS
2) Support from the Operating System
3) Physical USB ports
4) A USB Device
5) The correct USB cable for the device
6) Drivers either from the OS and/or the peripheral maker
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Does my Computer Support USB?
There are two programs available to check if your system is USB ready.
Although, neither of these programs is a guarantee that your computer will
provide trouble-free USB, both provide good indications of capability.
- Intel USB Check:
http://www.usbman.com/WebDrivers/Intel%20USB%20System%20Check/USBREADY.EXE
- Entrega USB Ready:
http://www.usbman.com/WebDrivers/Entrega%20USB%20Ready/USBREADY.EXE
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Identify the USB Host Controller:
All USB host controllers are NOT created equal. You should identify the
USB host controller type so that you will know how to proceed if you have
problems. For a "How To", go here:
Host Controller PCI / USB - How to identify - Win9X
http://www.usbman.com/Guides/HowTo_Identify_HostController.htm
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Cleanup the Device Manager / Windows Safe Mode:
From initial installation problems to suddenly not working USB, cleaning up
the Device Manager in Safe mode is the first step in Win9X troubleshooting.
Many hardware related problems in Windows can be traced to ghost and/or
duplicate device entries. Obsolete and/or duplicate devices can ONLY be
seen and removed from the Device Manager while in Windows Safe Mode.
For a good "How To", see here:
Clean-up Device Manager in SAFE MODE - Win9X:
http://www.usbman.com/Guides/Cleanup%20Device%20Manager%20Safe%20Mode.htm
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BIOS: Common BIOS Problems:
Many USB Problems are the result of improper settings in the BIOS. To
achieve proper USB connectivity the BIOS needs to be a properly working
partner.
BIOS: Enable USB in the BIOS:
USB is often disabled by Default in the BIOS. To enable USB in the BIOS
one or more of the following statements must be true.
BIOS: USB Keyboard - DOS or Enabled (Even if you have NO USB Keyboard)
Legacy USB Support - Enabled
and/or
Assign IRQ for USB - Enabled (Some combinations of OS and BIOS version
require this setting to be Disabled).
If there are NO references to USB in the BIOS setup, your BIOS Version Needs
To Be Updated.
BIOS: The BIOS version does NOT support USB:
Vintage 1996-97 motherboards, even those with USB pinouts (AT Style) almost
always require a BIOS update to achieve proper USB connectivity. Generally,
a BIOS date of June 1998 or newer is required for Win9x systems. A BIOS
date of October 1999 or newer is usually required for systems running
Windows 2000. New Operating Systems require new BIOS revisions.
***
BIOS: BIOS Help Links:
BIOS Agent - Free Software Reports Your BIOS Details and Configuration
http://www.unicore.com/biosagent/ba.exe
BadFlash - Good Information and Help
http://www.badflash.com/
CTBIOS - Small DOS program that identifies the BIOS and motherboard -
Program is in German but, you'll get the idea
http://www.usbman.com/WebDrivers/CTBIOS/ctbios15.zip
Wim's Bios Page - BIOS Help Site
http://www.wimsbios.com/
USBMan BIOS Download Site - Listed by Manufacturer
http://www.usbman.com/Guides/bios_update_sites.htm
Improperly updating the BIOS can render a system inoperable and unbootable.
Follow ALL manufacturers instructions carefully when updating the BIOS.
Clear the CMOS with the jumper (see manual) and reset all BIOS data before
rebooting to Windows.
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BIOS settings affecting USB:
BIOS settings that effect the operation of Universal Serial Bus are shown
optimized for USB. The most common BIOS settings that affect USB
performance are:
Over-clocking
Reset the FSB to Default
Aggressive memory settings (Turbo/Fast)
Reset to Normal or Default
Lack of usable IRQs
Com1 and Com2 can be disabled if not used, allowing the OS to use these
IRQs for other devices.
Plug and Play OS – Disabled
Older Win9x (Socket 7 based) systems may require this option to be Enabled
to allow Windows controlled IRQ Steering to operate correctly. Toggle ON
or OFF as your system requires. IRQs Assigned – Auto
Power Management – Disabled
The Operating System should control Power Management.
ACPI - Disabled
ACPI enabled in the BIOS is the source of many USB problems. If you are
having problems with USB, ACPI should be disabled. Unfortunately, simply
resetting the switch in the BIOS may not be enough. Normally, a reinstall
of the operating system will be necessary. Remember to backup your data
before you reinstall the OS. A clean install to a newly formatted hard
drive is the best remedy.
Clean Install Guide:
http://www.usbman.com/Guides/Clean%20Install%20of%20Windows.htm
Win2000 Common Problems
http://www.usbman.com/Win2000.htm#Common%20Problems
USB Keyboard – Enabled or DOS
Assign IRQ for USB – This setting varies by motherboard type. The
"rule of thumb" is, Enabled for Win2000 and Disabled for Win9X. Try both
settings if you are having problems.
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IRQ Steering:
Properly installed IRQ Steering is critical to correctly working USB. If
IRQ Steering is disabled the likely cause is improper BIOS settings. See the
section on BIOS Settings. To see what properly installed IRQ Steering looks
like, go here:
IRQ Steering - Properly Installed
http://www.usbman.com/Guides/irq%20steeriing.htm
IRQ Conflicts with USB:
Despite information to the contrary, USB does NOT like to share its IRQ with
another device, (IRQ Holder for PCI Steering is not considered another
device). If USB is sharing its IRQ with Audio, Video, NIC or Modem you will
very likely have problems with USB. (All OS except WinXP)
Free as many IRQs as possible in the BIOS. A good place to start is COM1
and/or COM2 if you have no external serial device attached to your computer.
(i.e Serial Mouse or Digital Camera) If you are using a USB printer you can
also Disable the Parallel port.
After disabling devices in the BIOS, you must boot into Windows Safe Mode
and delete the device from the Windows Device Manager (Win95-Win2000). If
the device is not removed from the Windows Device Manager while in Safe
Mode, Windows will continue to recognize the device and assign it an IRQ.
Moving peripheral cards to other available slots is also an effective method
of resolving IRQ conflicts. Each PCI slot is assigned an IRQ by Default.
Some PCI slots share an IRQ with USB. Avoid those slots. Check the
Mainboard Owners Manual for this information and use it as a guide to avoid
IRQ conflicts.
If freeing IRQs in the BIOS does not produce the desired result you can
manually assign an IRQ for a conflicting device in the Windows Device
Manager while in Safe Mode. If manually assigning IRQs you will need to
Disable Plug and Play OS in the BIOS, otherwise Windows will continue to
override the BIOS assignments. If the OS is installed in ACPI mode, IRQs
assigned in the BIOS will be ignored by the Operating System.
If you still cannot isolate USB to its own IRQ, changing the I/O range of
USB sometimes works.
Step-by-Step:
1. Boot to BIOS setup and disable ACPI
2. Go to the "Integrated Peripherals" section and disable both serial ports
if you are not using them.
3. Go to the "PnP/PCI" section and disable "PnP OS", "Auto" and "Reset
Configuration Data (aka ESCD Update)". The last is a momentary switch and
will be disabled each time you return here. It releases the BIOS lock on
IRQs and lets Windows take over.
4. Go to the Power Management section and disable all BIOS control of power
management.
5. Boot DIRECTLY to Windows Safe Mode. Remove all USB software in
Add/Remove Programs. Open Device Manager. Remove the USB root hub and
host controller *in that order*. Remove all USB drivers. Look for
duplicate or erroneous drivers and *remove them all*. Windows will
reinstall genuine devices.
6. If you have any SB16 emulation drivers, disable them in the hardware
profile (do not remove). These are DOS sound drivers and most don't need
them.
7. While still in Safe Mode, go to System Devices and disable Advanced Power
Management support.
8. Lastly, remove the drivers for sharing devices. Windows should reinstall
the drivers automatically.
Note:
Unplug all USB devices except USB Keyboard or Mouse before rebooting to
Windows Standard Mode.
At this point you have freed up 2 or 3 IRQs and reset Windows IRQ
assignments. You can reboot and reinstall your devices *as per
manufacturer's instructions*.
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Non-Intel USB Host Controllers (USB Problem Devices)
Non-Intel and older Intel USB host controllers account for the bulk of
problems when a user is trying to establish USB connectivity for the
first time.
Links Tips and Tricks for the most popular non-Intel USB host controllers:
VIA Tips and Tricks
http://www.usbman.com/Guides/VIA%20Tips%20and%20Tricks.htm
SiS Tips and Tricks
http://www.usbman.com/Guides/SiS%20USB%20Tips%20and%20Tricks.htm
ALi Tips and Tricks
http://www.usbman.com/Guides/ali_tips_and_tricks.htm
***
Older Intel USB Host Controllers:
Vintage 1996 - 97 motherboards, even those with USB pinouts, almost always
require a BIOS update to achieve proper USB connectivity. BIOS versions
dated before June 1998 usually do NOT provide acceptable USB support. If
the BIOS properly supports USB, installing a motherboard cable assembly
will allow you to take advantage of the onboard USB capability of the
motherboard.
***
Windows 98 & Me Error Message Resource Center:
Microsoft Knowledge Base Resource Center
http://support.microsoft.com/support/windows/topics/errormsg/emresctr.asp
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