System Board
Input/output Controller Hub 2 (82801BA)
Chapter 2
46
ICH2 Features
ICH2 Architecture
The ICH2 interface architecture ensures that the I/O subsystems, both PCI and the
integrated I/O features (for example, IDE, AC’97, and USB), receive adequate
bandwidths.
By placing the I/O bridge directly on the ICH2 interface, and no longer on the PCI bus,
the ICH2 architecture ensures that the I/O functions obtain the bandwidth necessary for
peak performance.
ICH2 PCI Bus Interface
The ICH2 PCI provides the interface to a PCI bus interface operating at 33MHz. This
interface implementation is compliant with PCI 2.2 specification, supporting as many as
five external PCI masters in addition to the ICH2 requests. The PCI bus can reach a
data transfer rate of 133MB/sec. The maximum PCI burst transfer can be between
256 bytes and 4KB. It also supports advanced snooping for PCI master bursting, and
provides a prefetch mechanism dedicated for IDE read.
For a list of ICH2 interrupts, see the table on page 60.
SMBus Controller
The System Management (SM) bus is a two-wire serial bus that runs at a maximum of
100kKHz. The SMBus host interface allows the processor to communicate with SMBus
slaves and an SMBus slave interface that allows external masters to activate
power-management events. The bus connects to sensor devices that monitor some of the
hardware functions of the system board, both during system boot and run-time.
For a description of the devices on the SMBus, see page 49. For information about the
MaxiLife ASIC, see page 51.
Low Pin Count Interface
The ICH2 implements the LPC interface 1.0 specification.
Enhanced USB Controller
The USB controller provides enhanced support for the Universal Host Controller
Interface (UHCI). This includes support that allows legacy software to use a USB-based
keyboard and mouse. The USB supports four stacked connectors on the back panel.
These ports are built into the ICH2, as standard USB ports.
The ICH2 is USB 1.1 compliant.
• FWH interface • 3.3V operation with 5V tolerant buffers for
IDE and PCI signals
• 241 BGA package • Alert-On-LAN (AOL) support
Feature Feature
