Troubleshooting
WADE-8041 User’s Manual
5-2
Improper disable operation
There are too many occasions where users disable a certain device/feature in one
application through BIOS setting. These variables may not be set back to the original
values when needed. These devices/features will certainly fail to be detected.
When the above conditions happen, it is strongly recommended to check the BIOS
settings. Make sure certain items are set as they should be. These include the COM1/
COM2/COM3/COM4 ports, USB ports, external cache, on-board VGA and Ethernet.
It is also very common that users would like to disable a certain device/port to
release IRQ resource. A few good examples are
Disable COM1/COM4 serial port to release IRQ #4
Disable COM2/COM3 serial port to release IRQ #3
Etc…
A quick review of the basic IRQ mapping is given below for your reference.
IRQ#
Description
IRQ #0
System timer
IRQ #1
Keyboard
IRQ #2
cascade
IRQ #3
COM2
IRQ #4
COM1
IRQ #5
PCI device
IRQ #6
PCI device
IRQ #7
Possibility used by LPT1
IRQ #8
RTC clock
IRQ #9
PCI device
IRQ #10
COM3
IRQ #11
COM4
IRQ #12
Mouse
IRQ #13
Mathprocessor : 686
IRQ #14
Fixed disk
IRQ #15
Probably not available
It is then very easy to find out which IRQ resource is ready for additional peripherals.
If IRQ resource is not enough, please disable some devices listed above to release
further IRQ numbers.
