Electronic specifications

Memory map
Address Range (hex)Amount

Function

 

 

 

0 to 07FFFFh

640 KB

DOS region, base system memory

 

 

 

0A0000h to 0BFFFFh

128 KB

Video or SMM memory

 

 

 

0C0000h and 0DFFFFh

128 KB

Expansion card BIOS and buffer area

 

 

 

0E0000h to 0FFFFFh

128 KB

System BIOS

 

 

 

0E0000h to 0EFFFFh

2 MB

Extended system BIOS

 

 

 

FC000000h to FFFFFFFFh

64 MB

PCI memory space

 

 

 

Interrupts

The following table reflects a typical configuration, but you can change these interrupts. Use this information to determine how to program each interrupt. The actual interrupt map is defined using configuration registers in the ICH5-R (I/O controller). I/O Redirection Registers in the I/O APIC are provided for each interrupt signal. The signals define hardware interrupt signal characteristics for APIC messages sent to local APIC(s).

Important If you disable an IDE controller to free the interrupt for that controller, you must physically unplug the IDE cable from the system board. Simply disabling the drive by configuring the BIOS option does not make the interrupt available.

ISA Interrupt

Description

 

 

IRQ0

Timer/counter, HPET #0 in legacy

 

replacement Mode. In APIC mode,

 

cascade from 8259 controller 1

 

 

IRQ1

Keyboard controller

 

 

IRQ2

Slave controller INTR output. In APIC

 

mode Timer/counter, HPET #0

 

 

IRQ3

Serial port A

 

 

IRQ4

Serial port B

 

 

IRQ5

Parallel port (not implemented)

 

 

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