s71ws512ne0bfwzz Meet Spansion Inc., s71ws512ne0bfwzz Datasheet - Page 29

• 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.

June 28, 2004 S71WS512NE0BFWZZ_00_A1
Advanced Sector Protection and Unprotection
tion. Note that if a Bank Address (BA) on the four uppermost address bits is
asserted during the third write cycle of the autoselect command, the host system
can read autoselect data from that bank and then immediately read array data
from the other bank, without exiting the autoselect mode.
To access the autoselect codes, the host system must issue the autoselect com-
mand via the command register, as shown in the
section. Refer to the
information.
This advanced security feature provides an additional level of protection to all
sectors against inadvertant program or erase operations.
The advanced sector protection feature disables both programming and erase op-
erations in a sector while the advanced sector unprotection feature re-enables
both program and erase operations in previously protected sectors. Sector pro-
tection/unprotection can be implemented using either or both of the two methods
Persistent/Password Sector Protection is achieved by using the software method
while the sector protection with WP# pin is achieved by using the hardware
method.
All parts default to operate in the Persistent Sector Protection mode. The cus-
tomer 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 will be used.
If the customer decides to continue using the Persistent Sector Protection
method, they must set the Persistent Mode Lock Bit. This will permanently set
the part to operate using only Persistent Sector Protection. However, if the cus-
tomer decides to use the Password Sector Protection method, they must set the
Password Mode Lock Bit. This will permanently set the part to operate using
only Password Sector Protection.
It is important to remember that setting either the Persistent Mode Lock Bit
or the Password Mode Lock 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. If both
are selected to be set at the same time, the operation will abort. This is
done so that it is not possible for a system program or virus to later set the Pass-
word Mode Locking Bit, which would cause an unexpected shift from the default
Persistent Sector Protection Mode into the Password Sector Protection Mode.
The device is shipped with all sectors unprotected. Optional Spansion
ming services enable programming and protecting sectors at the factory prior to
shipping the device. Contact your local sales office for more details.
Persistent Mode Lock Bit
A Persistent Mode Lock Bit exists to guarantee that the device remain in software
sector protection. Once programmed (set to “0”), the Persistent Mode Lock Bit
prevents programming of the Password Mode Lock Bit. This allows protection
Hardware method
Software method
Persistent Mode Lock Bit
Password Mode Lock Bit
A d v a n c e
S29WSxxxN MirrorBit™ Flash Family For Multi-chip Products (MCP)
"Autoselect Command
I n f o r m a t i o n
"Command Definition
Sequence" section for more
TM
Summary"
program-
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