V58C2128 datasheet(23/59 Pages) MOSEL

23 / 59 page

MOSEL VITELIC

V58C2128(804/404/164)S

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

Write Interrupted by a Read

A Burst Write can be interrupted by a Read command to any bank. If a burst write operation is interrupted

prior to the end of the burst operation, then the last two pieces of input data prior to the Read command must

be masked off with the data mask (DM) input pin to prevent invalid data from being written into the memory

array. Any data that is present on the DQ pins coincident with or following the Read command will be masked

off by the Read command and will not be written to the array. The memory controller must give up control of

both the DQ bus and the DQS bus at least one clock cycle before the read data appears on the outputs in

order to avoid contention. In order to avoid data contention within the device, a delay is required (t

CDLR) from

the last valid data input before a Read command can be issued to the device. It is illegal to interrupt a Write

with autoprecharge command with a Read command.

Write Interrupted by a Read Command Timing

Auto Refresh

The Auto Refresh command is issued by having CS, RAS, and CAS held low with CKE and WE high at the

rising edge of the clock. All banks must be precharged and idle for a t

RP(min) before the Auto Refresh com-

mand is applied. No control of the address pins is required once this cycle has started because of the internal

address counter. When the Auto Refresh cycle has completed, all banks will be in the idle state. A delay be-

tween the Auto Refresh command and the next Activate command or subsequent Auto Refresh command

must be greater than or equal to the t

RFC(min). Commands may not be issued to the device once an Auto

Refresh cycle has begun. CS input must remain high during the refresh period or NOP commands must be

registered on each rising edge of the CK input until the refresh period is satisfied.

Auto Refresh Timing

(CAS Latency = 2; Burst Length = 8)

T10

T11

Write

NOP

Read

NOP

CK, CK

Command

DQS

T12

D2 D3 D4 D5

D2 D3 D4 D5 D6

Data is masked

by Read command

Data is masked

by DM input

DQS input ignored

D0 D1

tWTR

T10

NOP

CK, CK

Command

CKE

T11

Auto Ref

ANY

High

Pre All

tRFC

tRP

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