System Support

Table 4-4.

PCI Interrupt Distribution

System Board

 

 

System Interrupts (PIRQ)

 

 

 

 

 

 

 

 

 

 

 

 

 

Connector

A

B

C

D

E

F

 

G

H

IDSEL

 

 

 

 

 

 

 

 

 

 

 

 

PCI slot 1

(J20)

--

--

--

--

A

B

 

C

D

AD16

 

 

 

 

 

 

 

 

 

 

 

 

PCI slot 2

(J21) [1]

--

--

--

--

D

A

 

B

C

AD17

 

 

 

 

 

 

 

 

 

 

 

 

PCI slot 3

(J22) [1]

--

--

--

--

C

D

 

A

B

AD18

 

 

 

 

 

 

 

 

 

 

 

 

NOTES:

[1] CMT only

The PCI interrupts can be configured by PCI Configuration Registers 60h..63h to share the standard ISA interrupts (IRQn).

The APIC mode is supported by Windows NT, Windows 2000, and Windows XP, Windows Vista, and Windows 7 operating systems. Systems running the Windows 95 or 98 operating system will need to run in 8259 mode.

4.3.2Direct Memory Access

Direct Memory Access (DMA) is a method by which a device accesses system memory without involving the microprocessor. Although the DMA method has been traditionally used to transfer blocks of data to or from an ISA I/O device, PCI devices may also use DMA operation as well. The DMA method reduces the amount of CPU interactions with memory, freeing the CPU for other processing tasks. For detailed information regarding DMA operation, refer to the data manual for the Intel 82801 PCH I/O Controller Hub.

Technical Reference Guide

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4-7