Manual Assignment of Interruptions. Part I

Similar to the assignment of a separate interruption to video card, it is possible to assign a separate interruption to USB-bus in BIOS. To do this, use the parameter “Assign IRQ for USB” which has got two values: Enabled and Disabled. This parameter should be turned on if you use two or more USB-devices simultaneously, for example mouse and scanner. Turn this parameter off if there are no USB-devices or you use only one device, for example only scanner or only digital camera.

The other opportunity to get the additional free interruption is to switch off a floppy-drive. The parameter “FDD IRQ Can Be Free” (Report No FDD For Win 95) enables to free up an interruption IRQ6. This parameter has got two values: Enabled and Disabled. But if a floppy drive is connected to a system, you must switch off its controller for freeing up an interruption. To do this, set a value “Disabled” for the parameter “Onboard FDC Controller” (FDC Function) in a section “Integrated Peripherals”.

Use the parameter “IRQ n Assigned to” (IRQn) for manual assignment of the rest resources the hardware interruptions, where n – a number of interruption. This parameter may have values describing the type of device for which this interruption can be assigned.

  • Legacy ISA (ISA/EISA) – an interruption for ISA-devices that do not support Plug and Play technology. The interruptions for such devices are assigned in accordance with Technical documentation;
  • PCI/ISA PnP (PCI/PnP) – an interruption for PCI or ISA-devices that support Plug and Play technology.