Intel 6 SERIES CHIPSET - DATASHEET 01-2011 Datasheet page 47

Introduction
The PCH supports LPC DMA, which is similar to ISA DMA, through the PCH's DMA
controller. LPC DMA is handled through the use of the LDRQ# lines from peripherals
and special encoding on LAD[3:0] from the host. Single, Demand, Verify, and
Increment modes are supported on the LPC interface.
The timer/counter block contains three counters that are equivalent in function to those
found in one 82C54 programmable interval timer. These three counters are combined
to provide the system timer function, and speaker tone. The 14.31818-MHz oscillator
input provides the clock source for these three counters.
The PCH provides an ISA-Compatible Programmable Interrupt Controller (PIC) that
incorporates the functionality of two, 82C59 interrupt controllers. The two interrupt
controllers are cascaded so that 14 external and two internal interrupts are possible. In
addition, the PCH supports a serial interrupt scheme.
All of the registers in these modules can be read and restored. This is required to save
and restore system state after power has been removed and restored to the platform.
Advanced Programmable Interrupt Controller (APIC)
In addition to the standard ISA compatible Programmable Interrupt controller (PIC)
described in the previous section, the PCH incorporates the Advanced Programmable
Interrupt Controller (APIC).
Universal Serial Bus (USB) Controllers
The PCH contains up to two Enhanced Host Controller Interface (EHCI) host controllers
that support USB high-speed signaling. High-speed USB 2.0 allows data transfers up to
480 Mb/s which is up to 40 times faster than full-speed USB. The PCH supports up to
fourteen USB 2.0 ports. All ports are high-speed, full-speed, and low-speed capable.
Please see
Gigabit Ethernet Controller
The Gigabit Ethernet Controller provides a system interface using a PCI function. The
controller provides a full memory-mapped or IO mapped interface along with a 64 bit
address master support for systems using more than 4 GB of physical memory and
DMA (Direct Memory Addressing) mechanisms for high performance data transfers. 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 configurable transmit and receive
FIFOs (up to 20 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 LAN controller can operate at multiple speeds (10/100/1000 MB/s) and 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. See
RTC
The PCH contains a Motorola MC146818B-compatible real-time clock with 256 bytes of
battery-backed RAM. The real-time clock performs two key functions—keeping track of
the time of day and storing system data, even when the system is powered down. The
RTC operates on a 32.768 KHz crystal and a 3 V battery.
The RTC also supports two lockable memory ranges. By setting bits in the configuration
space, two 8-byte ranges can be locked to read and write accesses. This prevents
unauthorized reading of passwords or other system security information.
Datasheet
Section 1.3 for details on SKU feature availability.
Section 5.3 for details.
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