V58C2128 datasheet(21/59 Pages) MOSEL

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MOSEL VITELIC

V58C2128(804/404/164)S

V58C2128(804/404/164)S Rev. 1.6 March 2002

Data Mask Function

The DDR SDRAM has a Data Mask function that is used in conjunction with the Write cycle, but not the

Read cycle. When the Data Mask is activated (DM high) during a Write operation, the Write is blocked (Mask

to Data Latency = 0).

When issued, the Data Mask must be referenced to both the rising and falling edges of Data Strobe.

Data Mask Timing

Burst Interruption

Read Interrupted by a Read

A Burst Read can be interrupted before completion of the burst by issuing a new Read command to any

bank. When the previous burst is interrupted, the remaining addresses are overridden with a full burst length

starting with the new address. The data from the first Read command continues to appear on the outputs until

the CAS latency from the interrupting Read command is satisfied. At this point, the data from the interrupting

Read command appears on the bus. Read commands can be issued on each rising edge of the system clock.

It is illegal to interrupt a Read with autoprecharge command with a Read command.

Read Interrupted by a Read Command Timing

(CAS Latency = Any; Burst Length = 8)

NOP

Write

CK, CK

Command

DQS

tDMDQSS

tDMDQSH

(CAS Latency = 2; Burst Length = 4)

ReadB

NOP

DA0 DA1 DB0 DB1

ReadA

DB2 DB3

CK, CK

Command

DQS

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