3C905B - Microsoft Windows 98 - BIOS has not assigned an interrupt (IRQ) Code 29

Symptoms:
One or more of the following symptoms may occur:
- Error: Code 29
- Error: "This device is disabled because the BIOS for the device did not give it an
IRQ - Code 29." This error may only occur on every other reboot.
- Yellow ! on network adapter
- After restarting Microsoft Windows 98 an interrupt is not assigned to the NIC
- Resources are changed after a reboot
-Red X on network adapter

Cause:
The Interrupt Request is assigned to PCI cards by the BIOS. This IRQ value must then be
communicated to the operating system. In order for a device to share an interrupt the following
requirements must be met: both devices must be able to share an interrupt, the motherboard
must support shared interrupts, and the BIOS must support shared interrupts. If any of these
requirements are not met then the NIC will not have an interrupt assigned.

Obtain the latest BIOS for the motherboard
1. Check with the motherboard manufacturer to determine what is the latest version
Note: Check the end of this document for more information on updating the BIOS

Workarounds if BIOS update is not available:
A. Set Microsoft Windows 98 to Get IRQ Table from Protected Mode PCIBIOS 2.1 call
1. Click START>SETTINGS>CONTROL PANEL
2. Double-click System
3. Click Device Manager tab
4. Double-click System Devices category
5. Double-click PCI bus
6. Click the IRQ Steering tab
7. Check this box: Get IRQ Table from Protected Mode PCIBIOS 2.1 call
8. Click OK
9. Do NOT restart the system
10. Click START>SHUT DOWN>SHUT DOWN THE COMPUTER?
11. Click Yes
12. Turn off the computer when prompted
13. Wait 10 seconds
14. Turn the computer back on

If the problem still occurs:
1. Click START>SETTINGS>CONTROL PANEL
2. Double-click System
3. Click Device Manager tab
4. Double-click System Devices category
5. Double-click PCI bus
6. Click the IRQ Steering tab
7. Uncheck these three boxes:
a. Get IRQ Table using ACPI BIOS
b. Get IRQ Table using MS SPecification table
c. Get IRQ Table from Real Mode PCIBIOS 2.1 call
8. Click OK
9. Restart Windows 98

Fact: Source: Microsoft KnowledgeBase
Fact: Source ID: Article ID: Q182604
Note: Information valid as of August 4, 1998

Other Workarounds:
If the BIOS allows, specify the IRQ for the 3C905B-TX by slot. This IRQ should match the value
that is displayed in the DOS diagnostics program.

Change the IRQ Activated by setting:
1. Restart the computer
2. Access the BIOS
Note: Refer to PC documentation for command to enter the BIOS
3. Find the section for: IRQ Activated by Level or Edge
Note: The section may be titled PCI/PnP Configuration
4. Change the value from Level to Edge
5. Save the changes and exit by pressing F10
Note: The key used to save the changes and exit may be different depending on which BIOS is being used

When obtaining a BIOS upgrade for the computer:
Note: Read the BIOS update instructions completely before updating a BIOS as performing the update incorrectly may destroy the BIOS. 3Com is not responsible for incorrectly flashed BIOS'. The following is a list of motherboards on which a BIOS update resolved the Code 29 error. The information is provided to assist our customers in locating the correct BIOS for their motherboard. If there is any question about which BIOS is correct for a motherboard, please contact the motherboard vendor or manufacturer.

Micron Millennia 30 MHZ (Endeavor) motherboard
GigaByte GA-5SG100 SIS5591AGP motherboard
Micro-Star MS-5169 motherboard
Note: In order to resolve the error for this motherboard: all four options on the IRQ steering tab
had to be checked and the latest BIOS installed
DFI P5BV3+ motherboard