s71gl128nc0 Meet Spansion Inc., s71gl128nc0 Datasheet - Page 55

• Manufacturer Part Number: s71gl128nc0
• Description: Stacked Multi-chip Product Mcp 512/256/128 Megabit 32/16/8 M X 16-bit Cmos 3.0 Volt-only Mirrorbittm Page-mode Flash Memory With 64 Megabit 4m X 16-bit Psram
• Manufacturer: Meet Spansion Inc.

December 15, 2004 S29GLxxxN_MCP_A1
Advanced Sector Protection
Lock Register
using the Persistent Sector Protection method, they must set the Persistent
Sector Protection Mode Locking Bit. This will permanently set the part to op-
erate only using Persistent Sector Protection. If the customer decides to use the
password method, they must set the Password Mode Locking Bit. This will
permanently set the part to operate only using password sector protection.
It is important to remember that setting either the Persistent Sector Protec-
tion 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 has been 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 unex-
pected 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
toselect Command Sequence” section on page 67
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.
The Lock Register consists of 3 bits (DQ2, DQ1, and DQ0). These DQ2, DQ1, DQ0
bits of the Lock Register are programmable by the user. Users are not allowed to
program both DQ2 and DQ1 bits of the Lock Register to the 00 state. If the user
tries to program DQ2 and DQ1 bits of the Lock Register to the 00 state, the device
will abort the Lock Register back to the default 11 state. The programming time
of the Lock Register is same as the typical word programming time without uti-
lizing the Write Buffer of the device. During a Lock Register programming
sequence execution, the DQ6 Toggle Bit I will toggle until the programming of the
Lock Register has completed to indicate programming status. All Lock Register
bits are readable to allow users to verify Lock Register statuses.
The Customer Secured Silicon Sector Protection Bit is DQ0, Persistent Protection
Mode Lock Bit is DQ1, and Password Protection Mode Lock Bit is DQ2 are acces-
sible by all users. Each of these bits are non-volatile. DQ15-DQ3 are reserved and
must be 1's when the user tries to program the DQ2, DQ1, and DQ0 bits of the
Lock Register. The user is not required to program DQ2, DQ1 and DQ0 bits of the
Lock Register at the same time. This allows users to lock the Secured Silicon Sec-
tor and then set the device either permanently into Password Protection Mode or
Persistent Protection Mode and then lock the Secured Silicon Sector at separate
instances and time frames.
Secured Silicon Sector Protection allows the user to lock the Secured Silicon
Sector area
A d v a n c e
S29GLxxxN MirrorBit
I n f o r m a t i o n
TM
Flash Family
for details.
“Au-
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