s71ws512ne0bfwzz Meet Spansion Inc., s71ws512ne0bfwzz Datasheet - Page 30

• Manufacturer Part Number: s71ws512ne0bfwzz
• Description: Stacked Multi-chip Product Mcp Flash Memoy And Psram Cmos 1.8 Volt, Simultaneous Operation, Burst Mode Flash Memory And Pseudo-static Ram
• Manufacturer: Meet Spansion Inc.

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Sector Protection
Persistent Sector Protection
from potential hackers locking the device by placing the device in password sec-
tor protection mode and then changing the password accordingly.
Password Mode Lock Bit
In order to select the Password Sector Protection scheme, the customer must first
program the password. Spansion LLC recommends that the password be some-
how correlated to the unique Electronic Serial Number (ESN) of the particular
flash device. Each ESN is different for every flash device; therefore each pass-
word should be different for every flash device. While programming in the
password region, the customer may perform Password Verify operations.
Once the desired password is programmed in, the customer must then set the
Password Mode Locking Bit. This operation achieves two objectives:
1.It permanently sets the device to operate using the Password Sector Protection
Mode. It is not possible to reverse this function.
2.It also disables all further commands to the password region. All program and
read operations are ignored.
Both of these objectives are important, and if not carefully considered, may lead
to unrecoverable errors. The user must be sure that the Password Sector Protec-
tion method is desired when setting the Password Mode Locking Bit. More
importantly, the user must be sure that the password is correct when the Pass-
word Mode Locking Bit is set. Due to the fact that read operations are disabled,
there is no means to verify what the password is after it is set. If the password
is lost after setting the Password Mode Lock Bit, there will be no way to clear the
PPB Lock Bit.
The Password Mode Lock Bit, once set, prevents reading the 64-bit password on
the DQ bus and further password programming. The Password Mode Lock Bit
is not erasable. Once the Password Mode Lock Bit is programmed, the Persistent
Mode Lock Bit is disabled from programming, guaranteeing that no changes to
the protection scheme are allowed.
The device features several levels of sector protection, which can disable both the
program and erase operations in certain sectors.
The Persistent Sector Protection method replaces the old 12 V controlled protec-
tion method while at the same time enhancing flexibility by providing three
different sector protection states:
Persistent Sector Protection: A software enabled command sector protection
method that replaces the old 12 V controlled protection method.
Password Sector Protection: A highly sophisticated software enabled protec-
tion method that requires a password before changes to certain sectors or
sector groups are permitted
WP# Hardware Protection: A write protect pin (WP#) can prevent program or
erase operations in the outermost sectors.The WP# Hardware Protection fea-
ture is always available, independent of the software managed protection
method chosen.
Persistently Locked—A sector is protected and cannot be changed.
Dynamically Locked—The sector is protected and can be changed by a simple
command
S29WSxxxN MirrorBit™ Flash Family For Multi-chip Products (MCP) S71WS512NE0BFWZZ_00_ A1 June 28, 2004
A d v a n c e
I n f o r m a t i o n