S70GL01GN00 Datasheet, PDF (36/83 Pages) SPANSION – 3.0 Volt-only Page Mode Flash Memory featuring 110 nm MirrorBit™ Process Technology

Advance Information
Both of these objectives are important, and if not carefully considered, may lead
to unrecoverable errors. The user must be sure that the Password Sector Protec-
tion method is desired when programming the Password Protection Mode Lock
Bit. More importantly, the user must be sure that the password is correct when
the Password Protection Mode Lock Bit is programmed. Due to the fact that read
operations are disabled, there is no means to read what the password is after-
wards. If the password is lost after programming the Password Protection Mode
Lock Bit, there is no way to clear and unfreeze the PPB Lock Bit. The Password
Protection Mode Lock Bit, once programmed, prevents reading the 64-bit pass-
word on the DQ bus and further password programming. The Password Protection
Mode Lock Bit is not erasable. Once Password Protection Mode Lock Bit is pro-
grammed, the Persistent Protection Mode Lock Bit is disabled from programming,
guaranteeing that no changes to the protection scheme are allowed.
64-bit Password
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 conjunction with the Password Protection Mode Lock Bit, which
when programmed, prevents the Password Read command from reading the con-
tents of the password on the pins of the device.
Persistent Protection Bit Lock (PPB Lock Bit)
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 Protec-
tion 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 exe-
cution of the Password Unlock command clears and unfreezes the PPB Lock Bit,
allowing for sector PPB bits to be modified. Without issuing the Password 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.
Secured Silicon Sector Flash Memory Region
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 permanently set at the factory and can-
not 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 (standard shipping option) or factory locked (contact an AMD sales rep-
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S70GL01GN00 MirrorBit^TM Flash
S70GL01GN00_00_A1 June 1, 2005