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Rev. 0A | October 2022

www.issi.com - dram@issi.com

IS43/46LR32320C

IS43/46LR16640C

Figure21 : Write Burst (BL=4)

Write

The WRITE command is used to initiate a Burst Write access to an active row. The value of BA0, BA1 selects the bank and address inputs

select the starting column location.

The value of A10 determines whether or not auto precharge is used.If autoprecharge is selected, the row being accessed will be precharged

at the end of the write burst; if auto precharge is not selected, the row will remain open for subsequent access. Input data appearing on the

data bus, is written to the memory array subject to the DM input logic level appearing coincident with the data. If a given DM signal is

registered low, the corresponding data will be written to the memory; if the DM signal is registered high, the corresponding data-inputs will

be ignored, and a write will not be executed to that byte/column location. The memory controller drives the DQS during write operations.

The initial low state of the DQS is known as the write preamble and the low state following the last data-in element is write postamble. Upon

completion of a burst, assuming no new commands have been initiated, the I/O's will stay high-Z and any additional input data will be

ignored.

Figure20 : Write command

Notes :

1. CA : Column address

2. BA : Bank address

3. A10=High : Enable Auto precharge

A10=Low : Disable Auto precharge

Notes:

1. Din n = Data-In from Column n.

CLK

/CLK

CKE

/CS

/RAS

/CAS

/WE

CA

A0~A9

A10

BA

BA0, BA1

Don’t care

Bank a

COL m

Bank a

COL n

WRITE

NOP

WRITE

/CLK

CLK

T0

T1

T2

T3

T1n

T2n

DQ

tDQSS

tWPST

Don’ t care

DQS

tWPRES

tWPRE

tDH

tDS

DM

DIN

n

DIN

n+1

DIN

n+2

DIN

n+3

Address

Command

tDQSH