S29GL512N SPANSION, S29GL512N Datasheet - Page 45

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

S29GL-N_00_B3 October 13, 2006
64-bit Password
Persistent Protection Bit Lock (PPB Lock Bit)
Secured Silicon Sector Flash Memory Region
The 64-bit Password is located in its own memory space and is accessible through the use of
the Password Program and Password Read commands. The password function works in con-
junction with the Password Protection Mode Lock Bit, which when programmed, prevents the
Password Read command from reading the contents of the password on the pins of the
device.
A global volatile bit. The PPB Lock Bit is a volatile bit that reflects the state of the Password
Protection Mode Lock Bit after power-up reset. If the Password Protection Mode Lock Bit is
also programmed after programming the Password, the Password Unlock command must be
issued to clear and unfreeze the PPB Lock Bit after a hardware reset (RESET# asserted) or a
power-up reset. Successful execution of the Password Unlock command clears and unfreezes
the PPB Lock Bit, allowing for sector PPB bits to be modified.
Unlock command, while asserting RESET#, taking the device through a power-on reset, or
issuing the PPB Lock Bit Set command sets the PPB Lock Bit to a the “freeze state”.
If the Password Protection Mode Lock Bit is not programmed, the device defaults to Persistent
Protection Mode. In the Persistent Protection Mode, the PPB Lock Bit is cleared to the unfreeze
state after power-up or hardware reset. The PPB Lock Bit is set to the freeze state by issuing
the PPB Lock Bit Set command. Once set to the freeze state the only means for clearing the
PPB Lock Bit to the “unfreeze state” is by issuing a hardware or power-up reset. The Password
Unlock command is ignored in Persistent Protection Mode.
Reading the PPB Lock Bit requires a 200ns access time.
The Secured Silicon Sector feature provides a Flash memory region that enables permanent
part identification through an Electronic Serial Number (ESN). The Secured Silicon Sector is
256 bytes in length, and uses a Secured Silicon Sector Indicator Bit (DQ7) to indicate whether
or not the Secured Silicon Sector is locked when shipped from the factory. This bit is perma-
nently set at the factory and cannot be changed, which prevents cloning of a factory locked
part. This ensures the security of the ESN once the product is shipped to the field.
The factory offers the device with the Secured Silicon Sector either customer lockable (stan-
dard shipping option) or factory locked (contact an AMD sales representative for ordering
information). The customer-lockable version is shipped with the Secured Silicon Sector un-
protected, allowing customers to program the sector after receiving the device. The
customer-lockable version also has the Secured Silicon Sector Indicator Bit permanently set
to a 0. The factory-locked version is always protected when shipped from the factory, and has
the Secured Silicon Sector Indicator Bit permanently set to a 1. Thus, the Secured Silicon Sec-
tor Indicator Bit prevents customer-lockable devices from being used to replace devices that
are factory locked.
The Secured Silicon sector address space in this device is allocated as follows:
The system accesses the Secured Silicon Sector through a command sequence (see “Write
Protect (WP#)”). After the system has written the Enter Secured Silicon Sector command se-
quence, it may read the Secured Silicon Sector by using the addresses normally occupied by
Secured Silicon Sector
000000h–000007h
000008h–00007Fh
Address Range
D a t a
Customer Lockable
S29GL-N MirrorBit™ Flash Family
Determined by
customer
S h e e t
ESN Factory Locked
Unavailable
ESN
ESN or determined by
Without issuing the Password
Factory Locked
Determined by
ExpressFlash
customer
customer
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