S71PL129JC0 Datasheet, PDF (33/149 Pages) SPANSION – Stacked Multi-Chip Product (MCP) Flash Memory

Advance Information
programmed. This prevents a program or virus from later setting the Password
Mode Locking Bit, which would cause an unexpected shift from the default Per-
sistent 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 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
June 4, 2004 S29PL129J_MCP_00_A0
S29PL129J for MCP
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