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參數(shù)資料
| 型號： | S29NS064N0SBJW002 |
| 廠商： | SPANSION LLC |
| 元件分類： | DRAM |
| 英文描述： | Simultaneous Read/Write, Multiplexed, Burst Mode Flash Memory |
| 中文描述： | 4M X 16 FLASH 1.8V PROM, 80 ns, PBGA44 |
| 封裝： | 7.70 X 6.20 MM, LEAD FREE, FBGA-44 |
| 文件頁數(shù)： | 23/86頁 |
| 文件大?。?/td> | 1036K |
| 代理商： | S29NS064N0SBJW002 |
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S29NS-N_00_A12 June 13, 2006
S29NS-N MirrorBit Flash Family
21
D a t a
S h e e t
( A d v a n c e
I n f o r m a t i o n )
8.14
Persistent Sector Protection
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:
Persistently Locked
—A 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 command
In order to achieve these states, three types of “bits” namely Persistent Protection Bit (PPB), Dynamic
Protection Bit (DYB), and Persistent Protection Bit Lock (PPB Lock) are used to achieve the desired sector
protection scheme:
8.14.1
Persistent Protection Bit (PPB)
PPB is used to as an advanced security feature to protect individual sectors from being programmed or
erased thereby providing additional level of protection. Every sector is assigned a Persistent Protection Bit.
Each PPB is individually programmed through the
PPB Program Command
. However all PPBs are erased
in parallel through the
All PPB Erase Command
. Prior to erasing, these bits don’t have to be pre
programmed. The Embedded Erase algorithm automatically preprograms and verifies prior to an electrical
erase. The system is not required to provide any controls or timings during these operations.
The PPBs retain their state across power cycles because they are Non-Volatile. The PPBs has the same
endurance as the flash memory.
8.14.2
Persistent Protection Bit Lock (PPB Lock Bit) in Persistent Sector Protection
Mode
PPB Lock Bit is a global volatile bit and provides an additional level of protection to the sectors. When
programmed (set to “0”)
, all the PPBs are locked and hence none of them can be changed. When
erased
(cleared to “1”)
, the PPBs are changeable. There is only one PPB Lock Bit in every device. Only a hardware
reset or a power-up clears the PPB Lock Bit. It is to be noted that there is no software solution, i.e. command
sequence to unlock the PPB Lock Bit.
Once all PPBs are configured to the desired settings, the PPB Lock Bit may be set (programmed to “0”). The
PPB Lock Bit is set by issuing the PPB Lock Bit Set Command. Programming or setting the PPB Lock Bit
disables program and erase commands to all the PPBs. In effect, the PPB Lock Bit locks the PPBs into their
current state. The only way to clear the PPB Lock Bit is to go through a hardware or power-up reset. System
boot code can determine if any changes to the PPB are needed e.g. to allow new system code to be
downloaded. If no changes are needed then the boot code can disable the PPB Lock Bit to prevent any
further changes to the PPBs during system operation.
8.14.3
Dynamic Protection Bit (DYB)
DYB is a security feature used to protect individual sectors from being programmed or erased inadvertently. It
is a volatile protection bit and is assigned to each sector. Upon power-up, the contents of all DYBs are set
(programmed to “0”). Each DYB can be individually modified through the DYB Set Command or the DYB
Clear Command.
The Protection Status for a particular sector is determined by the status of the PPB and the DYB relative to
that sector. For the sectors that have the PPBs cleared (erased to “1”), the DYBs control whether or not the
sector is protected or unprotected. By issuing the DYB Set or Clear command sequences, the DYBs will be
set (programmed to “0”) or cleared (erased to “1”), thus placing each sector in the protected or unprotected
state respectively. These states are the so-called Dynamic Locked or Unlocked states due to the fact that
they can switch back and forth between the protected and unprotected states. This feature allows software to
easily protect sectors against inadvertent changes yet does not prevent the easy removal of protection when
changes are needed. The DYBs maybe set (programmed to “0”) or cleared (erased to “1”) as often as
needed.
When the parts are first shipped, the PPBs are cleared (erased to “1”) and upon power up or reset, the DYBs
are set (programmed to “0”). The PPB Lock Bit defaults to the cleared state (erased to “1”) after power up and
the PPBs retain their previous state as they are non-volatile.
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| S29NS064N0SBJW003 | Simultaneous Read/Write, Multiplexed, Burst Mode Flash Memory |
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| S29NS064N0SBJW003 | 制造商:SPANSION 制造商全稱:SPANSION 功能描述:Simultaneous Read/Write, Multiplexed, Burst Mode Flash Memory |
| S29NS128J0LBAW00 | 制造商:SPANSION 制造商全稱:SPANSION 功能描述:110 nm CMOS 1.8-Volt only Simultaneous Read/Write, Burst Mode Flash Memories |
| S29NS128J0LBAW000 | 制造商:SPANSION 制造商全稱:SPANSION 功能描述:Burst Mode Flash Memories |
| S29NS128J0LBAW002 | 制造商:SPANSION 制造商全稱:SPANSION 功能描述:Burst Mode Flash Memories |
| S29NS128J0LBAW003 | 制造商:SPANSION 制造商全稱:SPANSION 功能描述:Burst Mode Flash Memories |
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