Introduction to the External Interfaces

Figure 4–1 21264/EV67 System and Bcache Interfaces

SysAddIn_L[14:0]

SysAddInClk_L

SysAddOut_L[14:0]

SysAddOutClk_L

SysVref

SysData_L[63:0]

SysCheck_L[7:0]

SysDataInClk_H[7:0]

SysDataOutClk_L[7:0]

SysDataInValid_L

SysDataOutValid_L

SysFillValid_L

BcAdd_H[23:4]

 

[23:4]

[23:6]

[23:6]

21264

Data

Tag

Status

BcLoad_L

 

 

 

BcData_H[127:0]

 

 

 

BcCheck_H[15:0]

 

 

 

BcDataInClk_H[7:0]

 

 

 

BcDataOutClk_ x[3:0]

 

 

 

BcDataOE_L

 

 

 

BcDataWr_L

 

 

 

BcTag_H[42:20]

 

 

 

BcTagInClk_H

 

 

 

BcTagOutClk_ x

 

 

 

BcVref

 

 

 

BcTagWr_L

 

 

 

BcTagOE_L

 

 

 

BcTagValid_H

 

 

 

BcTagDir ty_H

 

 

 

BcTagShared_H

 

 

 

BcTagParity_H

 

 

 

IRQ_H[5:0]

 

 

 

System

FM-05818B-EV67

4.1.1 System Interface

This section introduces the system (external) bus interface. The system interface is made up of two unidirectional 15-bit address buses, 64 bidirectional data lines, eight bidirectional check bits, two single-ended unidirectional clocks, and a few control pins. The 15-bit address buses provide time-shared address/command/ID in two or four GCLK cycles. The Cbox controls the system interface.

Alpha 21264/EV67 Hardware Reference Manual

Cache and External Interfaces 4–3

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Image 91
Compaq specifications System Interface, 21264/EV67 System and Bcache Interfaces