D a t a S h e e t
8.9
Sector Protection
The device features several levels of sector protection, which can disable both the program and erase
operations in certain sectors:
8.9.1
Persistent Sector Protection
A command sector protection method that replaces the old 12 V controlled protection method.
8.9.2
8.9.3
Password Sector Protection
A highly sophisticated protection method that requires a password before changes to certain sectors are
permitted
WP# Hardware Protection
A write protect pin that can prevent program or erase operations in the outermost sectors.
The WP# Hardware Protection feature is always available, independent of the software managed protection
method chosen.
8.9.4
Selecting a Sector Protection Mode
All parts default to operate in the Persistent Sector Protection mode. The customer must then choose if the
Persistent or Password Protection method is most desirable. There are two one-time programmable non-
volatile bits that define which sector protection method is used. If the customer decides to continue using the
Persistent Sector Protection method, they must set the Persistent Sector Protection Mode Locking Bit.
This permanently sets the part to operate only using Persistent Sector Protection. If the customer decides to
use the password method, they must set the Password Mode Locking Bit. This permanently sets the part to
operate only using password sector protection.
It is important to remember that setting either the Persistent Sector Protection Mode Locking Bit or the
Password Mode Locking Bit permanently selects the protection mode. It is not possible to switch between
the two methods once a locking bit is set. It is important that one mode is explicitly selected when the
device is first programmed, rather than relying on the default mode alone. This is so that it is not
possible for a system program or virus to later set the Password Mode Locking Bit, which would cause an
unexpected shift from the default Persistent Sector Protection Mode into the Password Protection Mode.
The device is shipped with all sectors unprotected. The factory offers the option of programming and
protecting sectors at the factory prior to shipping the device through the ExpressFlash™ Service. Contact
your sales representative for details.
It is possible to determine whether a sector is protected or unprotected. See Autoselect Command Sequence
on page 42 for details.
8.10 Advanced Sector Protection
Advanced Sector Protection features several levels of sector protection, which can disable both the program
and erase operations in certain sectors.
Persistent Sector Protection is a method that replaces the old 12V controlled protection method.
Password Sector Protection is a highly sophisticated protection method that requires a password before
changes to certain sectors are permitted.
30
S29GL-N MirrorBit® Flash Family
S29GL-N_01_09 November 16, 2007
SPANSION [ SPANSION ]
