
1-6
COMPONENT INTRODUCTION
Up to four Pentium Pro processors can be gluelessly interconnected on the Pentium Pro proces-
sor bus. These agents are bus masters, capable of supporting all the features described in this
document. The interface to the remainder of the system is represented by the high-speed I/O in-
terface and memory interface blocks. The memory interface block represents a path to system
memory capable of supporting over 500 Mbytes/second data bandwidth. The high-speed I/O in-
terface block provides a fast path to system I/O. Various implementations of these two blocks
can provide different cost vs. performance trade-offs. For example, more than one memory in-
terface or high-speed I/O interface may be included.
An MP system containing more than four Pentium Pro processors can be created based on clus-
ters that each contain four processors. Such a system can use cluster controllers that connect
Pentium Pro processor buses to a global memory bus. The Pentium Pro processor bus provides
appropriate protocol support for building external caches and memory directory-based systems.
1.4.
TERMINOLOGY CLARIFICATION
Some key definitions and concepts are introduced here to aid the understanding of this
document.
A ‘#” symbol after a signal name refers to an active low signal. This means that a signal is in
the active state (based on the name of the signal) when driven low. For example, when FLUSH#
is low a flush has been requested. When NMI is high, a Non-maskable interrupt has occurred.
In the case of lines where the name does not imply an active state but describes part of a binary
sequence (such as address or data), the ‘#’ symbol implies that the signal is inverted. For
example, D[3:0] = ‘HLHL’ refers to a hex ‘A’, and D#[3:0] = ‘LHLH’ also refers to a hex
‘A’. (H= High logic level, L= Low logic level)
Pentium Pro processor bus agents issue transactions to transfer data and system information.
A bus agent is any device that connects to the processor bus including the Pentium Pro proces-
sors themselves.
This specification refers to several classifications of bus agents.
•
Central Agent. Handles reset, hardware configuration and initialization, special transac-
tions, and centralized hardware error detection and handling.
•
I/O Agent. Interfaces to I/O devices using I/O port addresses. Can be a bus bridge to
another bus used for I/O devices, such as a PCI bridge.
•
Memory Agent. Provides access to main memory.
A particular bus agent can have one or more of several roles in a transaction.
•
Requesting Agent. The agent that issues the transaction.
•
Addressed Agent. The agent that is addressed by the transaction. Also called the Target
Agent. A memory or I/O transaction is addressed to the memory or I/O agent that
recognizes the specified memory or I/O address. A Deferred Reply transaction is addressed
to the agent that issued the original transaction. Special transactions are considered to be
issued to the central agent.
Содержание Pentium Pro Family
Страница 17: ...1 Component Introduction ...
Страница 26: ...2 Pentium Pro Processor Architecture Overview ...
Страница 27: ......
Страница 36: ...3 Bus Overview ...
Страница 62: ...4 Bus Protocol ...
Страница 105: ...5 Bus Transactions and Operations ...
Страница 126: ...6 Range Registers ...
Страница 131: ...7 Cache Protocol ...
Страница 135: ...8 Data Integrity ...
Страница 148: ...9 Configuration ...
Страница 161: ...10 Pentium Pro Processor Test Access Port TAP ...
Страница 172: ...11 Electrical Specifications ...
Страница 201: ...12 GTL Interface Specification ...
Страница 229: ...13 3 3V Tolerant Signal Quality Specifications ...
Страница 233: ...14 Thermal Specifications ...
Страница 239: ...15 Mechanical Specifications ...
Страница 241: ...15 2 MECHANICAL SPECIFICATIONS s Figure 15 1 Package Dimensions Bottom View ...
Страница 252: ...16 Tools ...
Страница 260: ...16 8 TOOLS Figure 16 4 Generic MP System Layout for Debug Port Connection ...
Страница 264: ...17 OverDrive Processor Socket Specification ...
Страница 290: ...A Signals Reference ...
Страница 320: ...Index ...
Страница 328: ......