Chapter 3 BIOS Setup
EC71813CLD2NA SERIES
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IRQ Assignment Table
There are 15 interrupt sources of the system. Some are occupied by the system
devices. Only the ones that are not occupied can be distributed. The ISA devices
claim to engross the interrupt. Only the plug and play ISA devices can be distributed
by the BIOS or the OS. And several PCI devices share one interrupt through the
distribution of BIOS or OS. The diagram below shows parts of the interrupt
distribution under X86 platform, but it does not show the interrupt source occupied by
the PCI devices.
Level
Function
IRQ0
System Timer
IRQ1
Standard 101/102 Key or Microsoft Keyboard
IRQ2
Programmable Interrupt Controller
IRQ3
COM#3#4
IRQ4
COM#1#2
IRQ5
Reserved
IRQ6
Reserved for FDD controller
IRQ7
Parallel Port
IRQ8
System CMOS/Real Time Clock
IRQ9
ACPI
IRQ10
COM#5#6
IRQ11
COM#7#10
IRQ12
PS/2 Mouse
IRQ13
Numeric Data Processor
IRQ14
Primary IDE
IRQ15
Reserved
