
Chapter 1. Overview
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Chapter 1
Overview
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This chapter gives an overview of the bus interface common to the 60x microprocessors. It
describes the operation and features of this interface, lists all the microprocessor signals,
shows differences between the three microprocessors in the use and number of signals, and
defines various operational subsets of signals, and in particular identifies those that are
required for any system.
This bus description documents the current operations and system implementation
information for the following PowerPC processors:
PowerPC 601 processor. The 601 is the first PowerPC processor and is designed
for desktop, server, and workstation implementations and is designed to support
implementation in multiprocessing systems.
PowerPC 603 processors. References to the 603 include the PowerPC 603e
processors unless otherwise specified. The 603 family for processors is optimized
for implementation in low-power systems, and includes bus support for power
management, but provides less support for multiprocessing than either the 601 or
604 families of processors.
PowerPC 604 processors. References to the 604 include the PowerPC 604e
processors unless otherwise specified. The 604 family of processors is designed for
implementation in desktop, workstation, and server systems and provides extensive
support both for multiprocessing and for power management.
Although this book can be used as a general guide for the PowerPC 602 processor, it does
not include descriptions of the specific operations that are unique to that processor.
1.1 PowerPC 60x Microprocessor Interface
The 601, 603, and 604 support a range of systems, including low-power and notebook
machines, low-cost desktop personal computers, high-performance workstations, and
multiprocessor server systems. To meet those needs, the interface to these processors was
defined with a minimum set of functions and 32-bit or 64-bit data bus modes, as well as
optional performance and function enhancement signals and modes.