Cache And External Interfaces; Introduction To The External Interfaces - Compaq 21264 Hardware Reference Manual

This chapter describes the 21264/EV67 cache and external interface, which includes the
second-level cache (Bcache) interface and the system interface. It also describes locks,
interrupt signals, and ECC/parity generation. It is organized as follows:
•

Introduction to the external interfaces

•
Physical address considerations
•
Bcache structure
•
Victim data buffer
•
Cache coherency
•
Lock mechanism
•
System port
•
Bcache port
•
Interrupts
Chapter 3 lists and defines all 21264/EV67 hardware interface signal pins. Chapter 9
describes the 21264/EV67 hardware interface electrical requirements.
4.1 Introduction to the External Interfaces
A 21264/EV67-based system can be divided into three major sections:
•
21264/EV67 microprocessor
•
Second-level Bcache
•
System interface logic
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The 21264/EV67 external interface is flexible and mandates few design rules, allowing
a wide range of prospective systems. The external interface is composed of the Bcache
interface and the system interface.
•
Input clocks must have the same frequency as their corresponding output clock. For
example, the frequency of SysAddInClk_L must be the same as
SysAddOutClk_L.
Alpha 21264/EV67 Hardware Reference Manual

Cache and External Interfaces

Optional duplicate tag store
Optional lock register
Optional victim buffers
Cache and External Interfaces
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