Datasheet
Intel
®
Xeon
®
Processor C5500/C3500 Series
February 2010 Datasheet, Volume 1
Order Number: 323103-001 105
Interfaces
2.4 Intel
®
QuickPath Interconnect (Intel
®
QPI)
Intel
®
QuickPath Interconnect (Intel
®
QPI) is an Intel-developed cache-coherent, link
based interface used for interconnecting processors, chipsets, bridges, and various
acceleration devices. There is one internal link between the core complex and the IIO
module and there may be one external link to the non-legacy processor or to an IOH.
This section discusses the external link.
2.4.1 Processor’s Intel
®
QuickPath Interconnect Platform Overview
Figure 43 represents a simplified block diagram of a dual processor (DP) Intel
®
Xeon
®
processor C5500/C3500 series platform, showing how the Intel
®
QPI bus is used to
interconnect the two processors. The QPI bus is used to seamlessly interconnect the
resources from one processor to another, whether it be one processor accessing data in
the memory managed by the alternate processor, one processor accessing a PCIe port
residing on the alternate processor, or a PCIe P2P transfer involving two PCIe ports
residing on different processors. The Intel
®
QPI physical layer, link layer, and protocol
layer are implemented in hardware. No special software or drivers are required, other
than firmware to initialize the Intel
®
QPI link.
The Intel
®
QPI link is a serial point-to-point connection, consisting of 20 lanes in each
direction. The Intel
®
QPI bus is the only method of exchanging data between the two
processors, there are no additional sideband signals. The Intel
®
QPI bus is gluelessly
connected between processors, no additional hardware required.
Figure 42. SMBus Memory (Byte Write, PEC enabled)
S 1110_1X0 W A Cmd = 10110100 A Mem Region A PEC A P
S 1110_1X0 W A Cmd = 00110100 A
S 1110_1X0 W A Cmd = 00110100 A Rsv[3:0] & Addr[11:8] A
S 1110_1X0 W A Cmd = 00110100 A
S 1110_1X0 W A Cmd = 00110100 A
S 1110_1X0 W A Cmd = 00110100 A
Addr[23:16] A PEC A P
PEC A P
Regoff [7:0] A PEC A P
Data [31:24] A
Data [23:16] A
S 1110_1X0 W A Cmd = 00110100 A
S 1110_1X0 W A Cmd = 01110100 A
Data [15:8] A
PEC A P
Data [7:0]
PEC A P
A
PEC A P
PEC A P