S29GL512N SPANSION, S29GL512N Datasheet - Page 41

• Manufacturer Part Number: S29GL512N
• Description: Page Mode Flash Memory
• Manufacturer: SPANSION

S29GL-N_00_B3 October 13, 2006
Lock Register
Persistent Sector Protection
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 aborts the Lock Register back to the default
11 state. The programming time of the Lock Register is same as the typical word program-
ming time without utilizing the Write Buffer of the device. During a Lock Register
programming sequence execution, the DQ6 Toggle Bit I toggles until the programming of the
Lock Register has completed to indicate programming status. All Lock Register bits are read-
able 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 accessible 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 Sector and then set the device either permanently into Password Protection
Mode or Persistent Protection Mode and then lock the Secured Silicon Sector at separate in-
stances and time frames.
The Persistent Sector Protection method replaces the old 12 V controlled protection method
while at the same time enhancing flexibility by providing three different sector protection
states:
In order to achieve these states, three types of “bits” are going to be used:
Dynamic Protection Bit (DYB)
A volatile protection bit is assigned for each sector. After power-up or hardware reset, the
contents of all DYB bits are in the “unprotected state”. Each DYB is individually modifiable
through the DYB Set Command and DYB Clear Command. When the parts are first shipped,
all of the Persistent Protect Bits (PPB) are cleared into the unprotected state. The DYB bits
and PPB Lock bit are defaulted to power up in the cleared state or unprotected state - meaning
the all PPB bits are changeable.
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 PPB bits cleared, the DYB bits control
whether or not the sector is protected or unprotected. By issuing the DYB Set and DYB Clear
command sequences, the DYB bits is protected or unprotected, thus placing each sector in
the protected or unprotected state. These are the so-called Dynamic Locked or Unlocked
Secured Silicon Sector Protection allows the user to lock the Secured Silicon Sector area
Persistent Protection Mode Lock Bit allows the user to set the device permanently to op-
erate in the Persistent Protection Mode
Password Protection Mode Lock Bit allows the user to set the device permanently to op-
erate in the Password Protection Mode
Dynamically Locked-The sector is protected and can be changed by a simple command
Persistently Locked-A sector is protected and cannot be changed
Unlocked-The sector is unprotected and can be changed by a simple command
Don’t Care
DQ15-3
D a t a
S29GL-N MirrorBit™ Flash Family
Password Protection
Mode Lock Bit
S h e e t
DQ2
Table 6. Lock Register
Persistent Protection
Mode Lock Bit
DQ1
Secured Silicon Sector
Protection Bit
DQ0
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