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S29PL127J/S29PL064J/S29PL032J for MCP
S29PL127J_064J_032J_MCP_00_A3 August 12, 2004
A d v a n c e I n f o r m a t i o n
It is possible to determine whether a sector is protected or unprotected. See Au-
toselect Mode for details.
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-
erwise, a previously erased sector PPBs can potentially be over-erased. The flash
device does not have a built-in means of preventing sector PPBs over-erasure.
Persistent Protection Bit Lock (PPB Lock)
The Persistent Protection Bit Lock (PPB Lock) is a global volatile bit. When set to
“1”, the PPBs cannot be changed. When cleared (“0”), the PPBs are changeable.
There is only one PPB Lock bit per device. The PPB Lock is cleared after power-
up or hardware reset. There is no command sequence to unlock the PPB Lock.
Dynamic Protection Bit (DYB)
A volatile protection bit is assigned for each sector. After power-up or hardware
reset, the contents of all DYBs is “0”. Each DYB is individually modifiable through
the DYB Write Command.
When the parts are first shipped, the PPBs are cleared, the DYBs are cleared, and
PPB Lock is defaulted to power up in the cleared state – meaning the PPBs are
changeable.
When the device is first powered on the DYBs power up cleared (sectors not pro-
tected). The Protection State for each sector is determined by the logical OR of
the PPB and the DYB related to that sector. For the sectors that have the PPBs
cleared, the DYBs control whether or not the sector is protected or unprotected.
By issuing the DYB Write command sequences, the DYBs will be set or cleared,
thus placing each sector in the protected or unprotected state. These are the so-
called Dynamic Locked or Unlocked states. They are called dynamic states be-
cause it is very easy to switch back and forth between the protected and
unprotected conditions. This allows software to easily protect sectors against in-