307013-003 Datasheet, PDF (108/848 Pages) Intel Corporation – Intel I/O Controller Hub 7

Functional Description
5.3
5.3.1
LAN Controller (B1:D8:F0) (Desktop and Mobile
Only)
The ICH7’s integrated LAN controller includes a 32-bit PCI controller that provides
enhanced scatter-gather bus mastering capabilities and enables the LAN controller to
perform high-speed data transfers over the PCI bus. Its bus master capabilities enable
the component to process high level commands and perform multiple operations; this
lowers processor utilization by off-loading communication tasks from the processor.
Two large transmit and receive FIFOs of 3 KB each, help prevent data underruns and
overruns while waiting for bus accesses. This enables the integrated LAN controller to
transmit data with minimum interframe spacing (IFS).
The ICH7 integrated LAN controller can operate in either full-duplex or half-duplex
mode. In full- duplex mode the LAN controller adheres with the IEEE 802.3x Flow
Control Specification. Half duplex performance is enhanced by a proprietary collision
reduction mechanism.
The integrated LAN controller also includes an interface to a serial (4-pin) EEPROM. The
EEPROM provides power-on initialization for hardware and software configuration
parameters.
From a software perspective, the integrated LAN controller appears to reside on the
secondary side of the ICH7’s virtual PCI-to-PCI bridge (see Section 5.1.6). This is
typically Bus 1, but may be assigned a different number, depending upon system
configuration.
The following summarizes the ICH7 LAN controller features:
• Compliance with Advanced Configuration and Power Interface and PCI Power
Management standards
• Support for wake-up on interesting packets and link status change
• Support for remote power-up using Wake on LAN* (WOL) technology
• Deep power-down mode support
• Backward compatible software with 82550, 82557, 82558 and 82559
• TCP/UDP checksum off load capabilities
• Support for Intel’s Adaptive Technology
LAN Controller PCI Bus Interface
As a Fast Ethernet controller, the role of the ICH7 integrated LAN controller is to access
transmitted data or deposit received data. The LAN controller, as a bus master device,
initiates memory cycles via the PCI bus to fetch or deposit the required data.
To perform these actions, the LAN controller is controlled and examined by the
processor via its control and status structures and registers. Some of these control and
status structures reside in the LAN controller and some reside in system memory. For
access to the LAN controller’s Control/Status Registers (CSR), the LAN controller acts
as a slave (in other words, a target device). The LAN controller serves as a slave also
while the processor accesses the EEPROM.
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Intel ^® ICH7 Family Datasheet