Expansion Cards

Floppy/IDE/IO Controllers

Troubleshooting Floppy/IDE/IO Controllers

VLB Controllers with 2 IDE channels.

eg. Kentech EVLSIO-V2-003

• IO chip: Goldstar Prime 2C
• IDE chip: Promise PDC20630

Issue: VLB IO Controller not working at the same time as VLB Graphics card

The board has 2 VLB slots, for some reason when both cards are installed the IO controller does not see the hard drive correctly. The primary and secondary IDE channels are not separated and the CDROM is not detected.

This might be because the FSB is too high, the VLB only supports max 33Hhz. What you can try (most VLB motherboards have this option), is to set the VLB wait states to 1 (there is usually a jumper on the motherboard for this). This is sometimes important if you increase your FSB to above 33MHz.

Try perhaps by changing the VLB wait state jumpers on the motherboard when you increase the FSB to 40MHz. There is also a VESA clock delay jumper that you can try.

I'm inclined to say rather go for a VLB graphics card. Unless you're running an operating system that utilizes 32-bit disk & file access (DOS is not one of them), you will not benefit from the 32-bit controller much. Windows 3.11 does provide support for both 32-bit disk and file access but, I've read that this causes problems.

BIOS Support

You can use an optical drive on the secondary channel without any need for BIOS support, if you want a HDD on secondary, you need to use XTIDE ROM or a controller with a BIOS.

This motherboard's BIOS only supports up to 2.1 GB HDD (in terms of capacity).

IDE supports up to four controllers, their resources are normally fixed. Ports are 01F0, 0170, 01E8, and 0168.

For a CD-ROM to work, the BIOS doesn't need to support secondary IDE. That's only needed for hard disk drives, since only these are accessed through int 13h.