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Microsoft KB Archive/182591

From BetaArchive Wiki

CardBus Cards Not Enumerated on Some PC Card Controllers


The information in this article applies to:

  • Microsoft Windows 95 OEM Service Release, versions 2.0, 2.1, 2.5


When you insert a CardBus PC Card in a computer running Microsoft Windows 95 OEM Service Release 2 (OSR2), the PC Card may not function properly.


This problem can occur when the CardBus PC Card is not enumerated properly. This issue is known to occur on computers that use the following PC Card controller chip sets:

  • Texas Instruments PCI1220
  • Texas Instruments PCI1221
  • Texas Instruments PCI1250
  • Texas Instruments PCI1250A

CLKRUN is a power-saving feature which turns off the clock signal to PC Cards when they are not in use. When this feature is implemented by the controllers listed above, these controllers do not automatically provide the number of clock cycles most PC Cards need in order to initialize.


This issue is resolved by the following updated file(s) for Windows 95 OEM Service Release 2(OSR2):

   PCI.VXD  version 4.00.1121  dated 3/27/98 11:21am  42,783 bytes 

NOTE: In addition to the above file, the updated files described in the following Microsoft Knowledge Base articles are also required for correct CardBus functionality:

Q168909 Query/Remove Support for CardBus Cards Hangs Computer

Q164224 Inserting PC Card in Dock with CardBus Card May Cause Reboot

Q164223 PC Cards May Not Be Recognized in Docking Station

Q163938 Inserting Multifunction PC Card May Hang Computer


Microsoft has confirmed this to be a problem in Microsoft Windows 95 OEM Service Release 2 (OSR2). An update to address this problem is now available, but is not fully regression tested and should be applied only to computers experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft does not recommend implementing this update at this time. Contact Microsoft Technical Support for additional information about the availability of this update.

This issue is resolved in Microsoft Windows 98.


You can use Device Manager to determine the chip set of your PC Card controller. To do this, follow these steps:

  1. Click Start, point to Settings, click Control Panel, and then double- click System.
  2. Click the Device Manager tab, and then double-click PCMCIA Socket branch to view the list of devices.

For additional information about issues resolved by updates to this component, please see the following articles in the Microsoft Knowledge Base:

Q173677 Audio Problems with Cirrus Logic PD6832 CardBus Controller

Q170324 CMD PCI-0646U Accessed in Compatibility Mode in OSR2

Q164873 PCI Device Not Configured and Resources Unassigned

Q164222 CardBus Card in Docking Station May Not Be Configured

Q163938 Inserting Multifunction PC Card May Hang Computer

Q159543 Intel ProShare PC Card May Hang Computer

Q159492 PC Card Device Not Enumerated When Reinserted

NOTE: Even with this update installed, the following CardBus cards may not function correctly:

  • Adaptec 1480 SCSI card (Note: Adaptec 1480A works correctly)
  • Melco UltraSCSI card
  • Madge Token-Ring card
  • Noteworthy video conferencing card

If you experience a problem with one of these cards which is not resolved by this update, please contact the manufacturer of the CardBus card to inquire about a possible hardware update to address this issue.

For information about an additional issue that may not be resolved by this update, please see the following article in the Microsoft Knowledge Base:

Q185073 CardBus Controller Displays Error Code 29 on IBM ThinkPad

Additional query words: pcmcia card bus

Keywords : kbhw osr2 win95
Issue type : kbprb
Technology : kbWin95search kbOPKSearch kbWin95OPKOSR25 kbWin95OPKOSR210

Last Reviewed: June 13, 2001
© 2001 Microsoft Corporation. All rights reserved. Terms of Use.