2 System Board

The Input/Output Controller Hub (82801AA)

AC’97 Controller

This controller, even though available in the ICH, is not used. The HP Kayak

 

PC Workstation uses the dedicated dual chip PCI solution of the CS4280

 

audio controller and the CS4297 Codec Audio Codec ‘97 (AC’97).

 

Refer to page 54 for information about the CS4280 and CS4297 audio

 

solution.
IDE ControllerThe IDE controller is implemented as part of the ICH chip and has PCI-

 

Master capability. Two independent ATA/66 IDE channels are provided with

 

two connectors per channel. Two IDE devices (one master and one slave)

 

can be connected per channel. In order to guarantee data transfer integrity,

 

Ultra-ATA cables must be used for Ultra-ATA modes (Ultra-ATA/33 and

 

Ultra-ATA/66).

 

The PIO IDE transfers of up to 14 Mbytes/sec and Bus Master IDE transfer

 

rates of up to 66 Mbytes/sec are supported. The IDE controller integrates

 

16 x 32-bit buffers for optimal transfers.

 

It is possible to mix a fast and a slow device, such as a hard disk drive and a

 

CD-ROM, on the same channel without affecting the performance of the fast

 

device. The BIOS automatically determines the fastest configuration that

 

each device supports.
DMA ControllerThe seven-channel DMA controller incorporates the functionality of two

 

82C37 DMA controllers. Channels 0 to 3 are for 8-bit count-by-byte

 

transfers, while channels 5 to 7 are for 16-bit count-by-word transfers (refer

 

to table on page 104 for allocated DMA channel allocations). Any two of the

 

seven DMA channels can be programmed to support fast Type-F transfers.

 

The ICH DMA controller supports the LPC (Low Pin Count) DMA. Single,

 

Demand, Verify and Incremental modes are supported on the LPC interface.

 

Channels 0-3 are 8-bit, while channels 5-7 are 16-bit. Channel 4 is reserved

 

as a generic bus master request.
Interrupt Controller

The Interrupt controller is equivalent in function to the two 82C59 interrupt

 

controllers. The two interrupt controllers are cascaded so that 14 external

 

and two internal interrupts are possible. In addition, the ICH supports a

 

serial interrupt scheme and also implements the I/O APIC controller. A table

 

on page 68 shows how the master and slave controllers are connected.

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