iiiiiPEM

PEM

PEM

PEM

PEM

2.4G

2.4G

2.4G

2.4G

2.4Gb SDRAM-DDR

b SDRAM-DDR

b SDRAM-DDR

b SDRAM-DDR

b SDRAM-DDR

AS4DDR32M72PBG

AS4DDR32M72PBG

Rev. 1.2 06/09

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

9

Austin Semiconductor, Inc.

NAME (FUNCTION)

CS#

RAS#

CAS#

WE#

ADDR

DESELECT (NOP)(9)

H

XXXX

NO OPERATION (NOP) (9)

L

H

H

H

X

ACTIVE (Select bank and activate row) (3)

L

L

H

H

Bank/Row

READ (Select bank and column, and start READ burst) (4)

L

H

L

H

Bank/Col

WRITE (Select bank and column, and start WRITE burst) (4)

L

H

L

L

Bank/Col

BURST TERMINATE (8)

L

H

H

L

X

PRECHARGE (Deactivate row in bank or banks) (5)

L

L

H

L

Code

AUTO REFRESH or SELF REFRESH (Enter self refresh mode) (6,7)

L

L

L

H

X

LOAD MODE REGISTER (2)

LLLL

Op-Code

TRUTH TABLE - DM OPERATION

NAME (FUNCTION)

DM

DQs

WRITE ENABLE (10)

L

Valid

WRITE INHIBIT (10)

H

X

TRUTH TABLE - COMMANDS (NOTE 1)

NOTES:

1 . CKE is HIGH for all commands shown except SELF REFRESH.

2 . A0-12 define the op-code to be written to the selected Mode Register.

BA0, BA1 select either the mode register (0, 0) or the extended mode

register (1, 0).

3. A0-12 provide row address, and BA0, BA1 provide bank address.

4. A0-8 provide column address; A10 HIGH enables the auto precharge

feature (non-persistent), while A10 LOW disables the auto precharge

feature; BA0, BA1 provide bank address.

5. A10 LOW: BA0, BA1 determine the bank being precharged. A10 HIGH:

All banks precharged and BA0, BA1 are “Don’t Care.”

6 . This command is AUTO REFRESH if CKE is HIGH; SELF REFRESH if

CKE is LOW.

7 . Internal refresh counter controls row addressing; all inputs and I/Os are

“Don’t Care” except for CKE.

8. Applies only to read bursts with auto precharge disabled; this command

is undefined (and should not be used) for READ bursts with auto

precharge enabled and for WRITE bursts.

9 . DESELECT and NOP are functionally interchangeable.

10. Used to mask write data; provided coincident with the corresponding

data.

READ

The READ command is used to initiate a burst read

access to an active row. The value on the BA0, BA1 inputs

selects the bank, and the address provided on inputs A0-

9 selects the starting column location. The value on input

A10 determines whether or not AUTO PRECHARGE is

used. If AUTO PRECHARGE is selected, the row being

accessed will be precharged at the end of the READ burst;

if AUTO PRECHARGE is not selected, the row will remain

open for subsequent accesses.

WRITE

The WRITE command is used to initiate a burst write

access to an active row. The value on the BA0, BA1 inputs

selects the bank, and the address provided on inputs A0-

9 selects the starting column location. The value on input

A10 determines whether or not AUTO PRECHARGE is

used. If AUTO PRECHARGE 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 accesses. Input data

appearing on the D/Qs iswritten to the memory array

subject to the DQM input logic level appearing coincident

with the data. If a given DQM signal is registered LOW, the

corresponding data will be written to memory; if the DQM

signal is registered HIGH, the corresponding data inputs

will be ignored, and a WRITE will not be executed to that

byte/column location.

PRECHARGE

The PRECHARGE command is used to deactivate the open

row in a particular bank or the open row in all banks. The

bank(s) will be available for a subsequent row access a

issued. Except in the case of concurrent auto precharge,

where a READ or WRITE command to a different bank is

allowed as long as it does not interrupt the data transfer in

the current bank and does not violate any other timing

parameters. Input A10 determines whether one or all banks

are to be precharged, and in the case where only one bank

is to be precharged, inputs BA0, BA1 select the bank.

Otherwise BA0, BA1 are treated as “Don’t Care.” Once a

bank has been precharged, it is in the idle state and must

be activated prior to any READ or WRITE commands being

issued to that bank. A PRECHARGE command will be

treated as a NOP if there is no open row in that bank (idle

state), or if the previously open row is already in the process

of precharging.