MX29LV640BU Macronix International, MX29LV640BU Datasheet - Page 16

• Manufacturer Part Number: MX29LV640BU
• Description: 64M-BIT [4M x 16] CMOS EQUAL SECTOR FLASH MEMORY
• Manufacturer: Macronix International

www.DataSheet4U.com
P/N:PM1081
SECURED SILICON SECTOR
The MX29LV640BU features a OTP region where the sys-
tem may access through a command sequence to cre-
ate a permanent part identification as so called Elec-
tronic Serial Number (ESN) in the device. Once this re-
gion is programmed, any further modification on the re-
gion is impossible. The secured silicon sector is a 128
words in length, and uses a Secured Silicon Sector Indi-
cator Bit (Q7) 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 cannot be
changed, which prevent duplication of a factory locked
part. This ensures the security of the ESN once the prod-
uct is shipped to the field.
The MX29LV640BU offers the device with Secured Sili-
con Sector either factory locked or customer lockable.
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". The cus-
tomer-lockable version is shipped with the Secured Sili-
con Sector unprotected, allowing customs to utilize that
sector in any form they prefer. The customer-lockable
version has the secured sector Indicator Bit permanently
set to a "0". Therefore, the Secured Silicon Sector Indi-
cator Bit permanently set to a "0". Therefore, the Sec-
ond Silicon Sector Indicator Bit prevents customer, lock-
able device 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 access the Secured Silicon Sector through
a command sequence (refer to "Enter Secured Silicon/
Exit Secured Silicon Sector command Sequence). After
the system has written the Enter Secured Silicon Sector
command sequence, it may read the Secured Silicon
Sector by using the address normally occupied by the
first sector (SA0). This mode of operation continues until
Secured Silicon Standard
Sector Address Factory
Range
000000h-
000007h
000008h-
00007Fh
Locked
ESN
Unavailable Determined
Express Flash Customer
Factory
Locked
ESN or
Determined
by Customer
by Customer
Lockable
Determined
by
Customer
16
the system issues the Exit Secured Silicon Sector com-
mand sequence, or until power is removed from the de-
vice. On power-up, or following a hardware reset, the
device reverts to sending command to sector SA0.
FACTORY LOCKED:Secured Silicon Sector
Programmed and Protected At the Factory
In device with an ESN, the Secured Silicon Sector is
protected when the device is shipped from the factory.
The Secured Silicon Sector cannot be modified in any
way. A factory locked device has an 8-word random ESN
at address 000000h-000007h.
CUSTOMER LOCKABLE:Secured Silicon
Sector NOT Programmed or Protected At the
Factory
As an alternative to the factory-locked version, the device
may be ordered such that the customer may program
and protect the 128-word Secured Silicon Sector.
Programming and protected the Secured Silicon Sector
must be used with caution since, once protected, there
is no procedure available for unprotecting the Secured
Silicon Sector area and none of the bits in the Secured
Silicon Sector memory space can be modified in any
way.
The Secured Silicon Sector area can be protected using
one of the following procedures:
Write the three-cycle Enter Secured Silicon Sector Region
command sequence, and then follow the in-system
sector protect algorithm as shown in Figure 14, except
that RESET# may be at either VIH or VID. This allows in-
system protection of the Secured Silicon Sector without
raising any device pin to a high voltage. Note that method
is only applicable to the Secured Silicon Sector.
Write the three-cycle Enter Secured Silicon Sector Region
command sequence, and then alternate method of sector
protection described in the :Sector Group Protection and
Unprotect" section.
Once the Secured Silicon Sector is programmed, locked
and verified, the system must write the Exit Secured
Silicon Sector Region command sequence to return to
reading and writing the remainder of the array.
MX29LV640BU
REV. 1.0, MAR. 08, 2005