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E.3 dual-data rate ssrams, Dual-data rate ssrams, Dual-data rate ssram data pin usage – Compaq 21264 User Manual

Page 325: E.3 dual-data rate ssrams

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Alpha 21264/EV67 Hardware Reference Manual 21264/EV67-to-Bcache Pin Interconnections

E–3

Dual-Data Rate SSRAMs

E.3 Dual-Data Rate SSRAMs

Table E–4 provides the data pin connections between dual-data rate SSRAMs and the
21264/EV67 or the system board. Table E–5 provides the same information for the tag
pins.

Data and Tag Pin Usage

Set from board to 1/2 the 21264/EV67 core voltage

CK_L

Set from board to 1/2 the 21264/EV67 core voltage

VREF1_H
VREF2_H

Set from board (implementation dependent)

ZQ_H

BcTagValid_H

DQx

BcTagDirty_H

DQx

BcTagShared_H

DQx

Unconnected

TMS_H

Unconnected

TDI_H

Unconnected

TCK_H

Unconnected

TDC_H

Table E–4 Dual-Data Rate SSRAM Data Pin Usage

21264/EV67 Signal Name or Board
Connection

Dual-Data Rate SSRAM Data Pin Name

BcAdd_H[21:4]

SA_H[17:0]

BcData_H[33:20]/
BcCheck_H[15:0]

DQx

BcLoad_L

LD_L (B1)

BcDataWr_L

R/W_L(B2)

From board, pulled up to VDD

LBO_L

From board, pulled down to VSS

Q_L

BcDataInClk_H

CQ_H

BcDataOutClk_H

CK_H

BcDataOutClk_L

CK_L

Set from board to 1/2 the 21264/EV67 core
voltage

VREF1_H
VREF2_H

Set from board (implementation-dependent)

ZQ_H

Unconnected or terminated

CQ_L

From board, pulled up to VDD

TCK_H

Unconnected

TDO_H

Table E–3 Late-Write Non-Bursting SSRAMs Tag Pin Usage (Continued)

21264/EV67 Signal Name or Board Connection

Late-Write SSRAM Tag Pin Name