JS48F4400PCZ00 datasheet(74/102 Pages) NUMONYX

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Numonyx™ Wireless Flash Memory (W18)

Datasheet

November 2007

Order Number: 290701-18

Numonyx™ Wireless Flash Memory (W18)

13.1.7

WP# Lock-Down Control

The Write Protect signal, WP#, adds an additional layer of block security. WP# only

affects blocks that once had the Lock-Down command written to them. After the lock-

down status bit is set for a block, asserting WP# forces that block into the lock-down

state [011] and prevents it from being unlocked. After WP# is deasserted, the block’s

state reverts to locked [111] and software commands can then unlock the block (for

erase or program operations) and subsequently re-lock it. Only device reset or power-

down can clear the lock-down status bit and render WP# ineffective.

13.2

Protection Register

The Numonyx Wireless Flash Memory (W18) includes a 128-bit Protection Register. This

protection register is used to increase system security and for identification purposes.

The protection register value can match the flash component to the system’s CPU or

ASIC to prevent device substitution.

The lower 64 bits within the protection register are programmed by Numonyx with a

unique number in each flash device. The upper 64 OTP bits within the protection

segment can be locked to prevent further programming.

Note:

The individual bits of the user segment of the protection register are OTP, not the

desired. After the protection register is locked, however, the entire user segment is

locked and no more user bits can be programmed.

Figure 32: Locking Operations Flowchart

Start

Write 60h

Block Address

Write 90h

BBA + 02h

Read Block Lock

Status

Locking

Change?

Lock Change

Complete

Write 01,D0,2Fh

Block Address

Write FFh

Partition Address

Yes

Write

(Optional)

Read

(Optional)

Standby

(Optional)

Write

Lock

Setup

Lock,

Unlock, or

Lockdown

Confirm

Read ID

Plane

Block Lock

Status

Read

Array

Data = 60h

Addr = Block to lock/unlock/lock-down (BA)

Data = 01h (Lock block)

D0h (Unlock block)

2Fh (Lockdown block)

Addr = Block to lock/unlock/lock-down (BA)

Data = 90h

Addr = BBA + 02h

Block Lock status data

Addr = BBA + 02h

Confirm locking change on DQ[1:0].

(See Block Locking State Transitions Table

for valid combinations.)

Data = FFh

Addr = Any address in same partition

Bus

Operation

Command

Comments

LOCKING OPERATIONS PROCEDURE

JS48F4400PCZ00 Datasheet(PDF) 74 Page - Numonyx B.V

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