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May 21, 2004 S29PL127_064_032J_00_A1
S29PL127J/S29PL064J/S29PL032J for MCP
49
Prelimin ary
Password Mode Locking Bit permanently sets the device to the Password Sec-
tor Protection mode. It is not possible to switch between the two protection
modes once a locking bit has been set. One of the two modes must be se-
lected when the device is first programmed. This prevents a program or
virus from later setting the Password Mode Locking Bit, which would cause an un-
expected shift from the default Persistent Sector Protection Mode into the
Password Protection Mode.
The device is shipped with all sectors unprotected. Optional Spansion program-
ming services enable programming and protecting sectors at the factory prior to
shipping the device. Contact your local sales office for details.
It is possible to determine whether a sector is protected or unprotected. See the
Persistent Sector Protection
The Persistent Sector Protection method replaces the 12 V controlled protection
method in previous Flash devices. This new method provides three different sec-
tor protection states:
Persistently Locked—The sector is protected and cannot be changed.
Dynamically Locked—The sector is protected and can be changed by a simple
command.
Unlocked—The sector is unprotected and can be changed by a simple com-
mand.
To achieve these states, three types of “bits” are used:
Persistent Protection Bit
Persistent Protection Bit Lock
Persistent Sector Protection Mode Locking Bit
Persistent Protection Bit (PPB)
A single Persistent (non-volatile) Protection Bit is assigned to a maximum four
sectors (see the sector address tables for specific sector protection groupings).
All 4 Kword boot-block sectors have individual sector Persistent Protection Bits
(PPBs) for greater flexibility. Each PPB is individually modifiable through the PPB
Write Command.
The device erases all PPBs in parallel. If any PPB requires erasure, the device
must be instructed to preprogram all of the sector PPBs prior to PPB erasure. Oth-
Table 12. Sector Protection Schemes
DYB
PPB
PPB Lock
Sector State
0
Unprotected—PPB and DYB are changeable
0
1
Unprotected—PPB not changeable, DYB changeable
0
1
0
Protected—PPB and DYB are changeable
1
0
1
0
1
Protected—PPB not changeable, DYB is changeable
1
0
1