20

Rev. 0A | October 2022

www.issi.com - dram@issi.com

IS43/46LR32320C

IS43/46LR16640C

Note:

1. The table applies when both CKEn-1 and CKEn are HIGH, and after tXSR or tXP has been met if the previous state was Self Refresh or

Power Down.

2. DESELECT and NOP are functionally interchangeable.

3. All states and sequences not shown are illegal or reserved.

4. This command may or may not be bank specific. If all banks are being precharged, they must be in a valid state for precharging.

5. A command other than NOP should not be issued to the same bank while a READ or WRITE Burst with auto precharge is enabled.

6. The new Read or Write command could be auto precharge enabled or auto precharge disabled.

7. Current State Definitions:

Idle: The bank has been precharged, and tRP has been met.

Row Active: A row in the bank has been activated, and tRCD has been met.

No data bursts/accesses and no register accesses are in progress.

Read: A READ burst has been initiated, with AUTO PRECHARGE disabled, and has not yet terminated or been terminated.

Write: a WRITE burst has been initiated, with AUTO PRECHARGE disabled, and has not yet terminated or been terminated.

8. The following states must not be interrupted by a command issued to the same bank.

DESELECT or NOP commands or allowable commands to the other bank should be issued on any clock edge occurring during these

states. Allowable commands to the other bank are determined by its current state and Truth Table3, and according to Truth Table 4.

• Precharging: Starts with the registration of a PRECHARGE command and ends when tRP is met.

Once tRP is met, the bank will be in the idle state.

• Row Activating: Starts with registration of an ACTIVE command and ends when tRCD is met.

Once tRCD is met, the bank will be in the ''row active'' state.

• Read with AP Enabled: Starts with the registration of the READ command with AUTO PRECHARGE enabled and ends when tRP has

been met. Once tRP has been met, the bank will be in the idle state.

• Write with AP Enabled: Starts with registration of a WRITE command with AUTO PRECHARGE enabled and ends when tRP has been

met. Once tRP is met, the bank will be in the idle state.

Table7 : Current State BANK

n Truth Table(COMMAND TO BANK n)

Current State

Command

Action

Note

/CS

/RAS

/CAS

/WE

Description

Any

H

X

X

X

DESELECT(NOP)

Continue previous Operation

L

H

H

H

NOP

Continue previous Operation

Idle

L

L

H

H

ACTIVE

Select and activate row

L

L

L

H

AUTO REFRESH

Auto refresh

10

L

L

L

L

MODE REGISTER

SET

Mode register set

10

L

L

H

H

PRECHARGE

No action if bank is idle

Row Active

L

H

L

H

READ

Select Column & start read burst

L

H

L

L

WRITE

Select Column & start write burst

L

L

H

L

PRECHARGE

Deactivate Row in bank (or banks)

4

Read

(without Auto

recharge)

L

H

L

H

READ

Truncate Read & start new Read burst

5,6

L

H

L

L

WRITE

Truncate Read & start new Write burst

5,6,13

L

L

H

L

PRECHARGE

Truncate Read, start Precharge

L

H

H

L

BURST TERMINATE

Burst terminate

11

Write

(without Auto

precharge)

L

H

L

H

READ

Truncate Write & start new Read burst

5,6,12

L

H

L

L

WRITE

Truncate Write & start new Write burst

5,6

L

L

H

L

PRECHARGE

Truncate Write, start Precharge

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