82801BA Datasheet, PDF (75/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

Functional Description
Note: This feature is not recommended for use in non-cache line oriented systems since it may cause
shorter bursts and lower performance.
Note: This feature should be used only when the CLS register in PCI Configuration space is set to 8 or
16.
Note: The LAN Controller reads all control data structures (including Receive Buffer Descriptors) from
the first DWord (even if it is not required) to maintain cache line alignment.
Error Handling
Data Parity Errors: As an initiator, the LAN Controller checks and detects data parity errors that
occur during a transaction. If the Parity Error Response bit is set (PCI Configuration Command
register, bit 6), the LAN Controller also asserts PERR# and sets the Data Parity Detected bit (PCI
Configuration Status register, bit 8). In addition, if the error was detected by the LAN Controller
during read cycles, it sets the Detected Parity Error bit (PCI Configuration Status register, bit 15).
5.2.3
CLOCKRUN# Signal (82801BAM ICH2-M only)
The ICH2-M receives a free-running 33 MHz clock. It does not stop based on the CLKRUN#
signal and protocol. When the LAN controller runs cycles on the PCI bus, the ICH2-M makes sure
that the STP_PCI# signal is high indictating that the PCI clock is running. This is to make sure that
any PCI tracker will not get confused by transactions on the PCI bus with its PCI clock stopped.
5.2.3.1
PCI Power Management
Enhanced support for the power management standard, PCI specification rev. 2.2, is provided in
the ICH2 integrated LAN Controller. The LAN Controller supports a large set of wake-up packets
and the capability to wake the system from a low power state on a link status change. The LAN
Controller enables the host system to be in a sleep state and remain virtually connected to the
network.
After a power management event or link status change is detected, the LAN Controller will wake
the host system. The sections below describe these events, the LAN Controller power states, and
estimated power consumption at each power state.
82801BA ICH2 and 82801BAM ICH2-M Datasheet
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