s29gl128n Meet Spansion Inc., s29gl128n Datasheet - Page 40

• Manufacturer Part Number: s29gl128n
• Description: 3.0 Volt-only Page Mode Flash Memory Featuring 110 Nm Mirrorbit ?rocess Technology
• Manufacturer: Meet Spansion Inc.

38
Sector Protection
Advanced Sector Protection
The device features several levels of sector protection, which can disable both the program
and erase operations in certain sectors or sector groups:
Persistent Sector Protection
A command sector protection method that replaces the old 12 V controlled protection method.
Password Sector Protection
A highly sophisticated protection method that requires a password before changes to certain
sectors or sector groups 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 man-
aged protection method chosen.
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. I t is important
that one mode is explicit ly 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 pro-
gram 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 program-
ming 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
mand Sequence‚ on page 51
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 Prot ection is a highly sophisticated protection method that requires a
password before changes to certain sectors are permitted.
S29GL-N MirrorBit™ Flash Family
for details.
D a t a
S h e e t
S29GL-N_00_B3 October 13, 2006
Autoselect Com-