Interphase EISA Adapter Doesn't Support EISA Bus Preemption

 Last reviewed: March 31, 1997
Article ID: Q161721
The information in this article applies to:
  • Microsoft Windows NT Workstation versions 3.5, 3.51, and 4.0
  • Microsoft Windows NT Server versions 3.5, 3.51, and 4.0

SYMPTOMS

The Cisco/Interphase EISA FDDI/CDDI adapters do not support EISA bus preemption. This may result in the adapter's being incompatible with PCs using a dual/split PCI/EISA I/O bus.

The following models of Cisco/Interphase EISA FDDI/CDDI network adapters:

  • WA-C321T-PC
  • WA-C323T-PC
  • WA-C326T-PC
  • WA-C328T-PC

can cause intermittent system resets or crashes with STOP: 0X0000000A.

Some PC systems that are known to exhibit this symptom include:

  • IBM PC Server 320 CYO
  • Compaq Proliant series (some models)
  • ALR Revolution Quad6

CAUSE

The Interphase EISA FDDI/CDDI adapter requires guaranteed access time (GAT) to function properly. PCs that implement EISA bus preemption without also supporting GAT will experience problems. The symptom is intermittent and occurs when both the FDDI adapter and a PCI device are active.

The adapter design predates implementation of the EISA bus preemption feature as described in EISA specification 3.12 (PCI/EISA systems shipped after 9/1/95).

In PCs with both a PCI and an EISA bus, PCI devices are allowed access to system memory even if the EISA bus has been granted control. Because the adapter requires GAT, and because PCI devices are able to de-assert the EXRDY (external ready) signal to the EISA bus, the adapter will stall and not finish its transfer to memory.

WORKAROUND

If you are experiencing this problem, first contact your system vendor to see if your PC supports GAT mode. If your PC does not support GAT, consider the following two workarounds:

  • Reduce adapter transfer burst size from 64 bytes to 32 bytes. This
reduces burst transfer time and has a positive effect on some systems. This can be changed in the registry entries for the drivers (C320tnt.sys). To make this change, follow the steps listed below:

WARNING: Using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk. 

  1. Run Regedt32 and select the HKEY_LOCAL_MACHINE Window
  2. Go to SYSTEM\CurrentControlSet\Services\c320tnt1\parameters
  3. Change the "BurstSize" from 63 (3F hex) to 31 (1F hex)
  • An alternative for adding FDDI connectivity, for systems with PCI slots, is the Interphase PCI/FDDI 5511.

    NOTE: Don't use an EISA adapter in PCs with active PCI devices. Use the adapter only in PCs that have an EISA bus.

    MORE INFORMATION

    Additional information can be obtained from Interphase at the following URL: 

       http://www.iphase.com/Public/AppEng/prodsup/c32x/EISAFDD2

   Interphase Corporation
   13800 Senlac
   Dallas, TX 75234-8823
   Technical Support: +1.214.654.5555
   E-mail: intouch@iphase.com
   World Wide Web: http://www.iphase.com
   Anonymous FTP: ftp.iphase.com
    The products discussed here are manufactured by Cisco and Interphase, vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding the products' performance or reliability.

    The third-party contact information included in this article is provided to help you find the technical support you need. This contact information is subject to change without notice. Microsoft in no way guarantees the accuracy of this third-party contact information.

    • Additional query words:
    Keywords : kb3rdparty kbhw nthw NTSrvWkst ntstop
    Version : 3.5 3.51 4.0
    Platform : WinNT

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    Last reviewed: March 31, 1997
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