ADVANCED INFORMATION
SECURITY SECTOR
The security sector of the ES29DL320 device pro-
vides an extra flash memory space that enables
permanent part identification through an Electronic
Serial Number (ESN). The security sector uses a
Security
Lock-Indicator Bit (DQ7)
to indicate
whether or not the security sector is locked when
shipped from the factory. This bit is permanently set
at the factory and cannot be changed, which pre-
vents cloning of a factory locked part. This ensures
the security of the ESN once the product is shipped
to the field. Note that the ES29DL320 has a secu-
rity sector size of
256 bytes.
E S I
I
ES
Excel Semiconductor inc.
- A random, secure ESN (16 bytes ) only
- Customer code through the ESI’s special-code
service
- Both a random, secure ESN and customer
code through the ESI’s special-code service.
ESN ( Electronic Serial Number )
In devices that have an ESN, a Bottom Boot device
will have the 16-byte (8-word) ESN in sector 0 at
addresses 000000h-00000Fh in byte mode (or
000000h-000007h in word mode). In the Top Boot
device the ESN will be in sector 70 at addresses
3FFF00h-3FFF0Fh in byte mode (or 1FFF80h-
1FFF87h in word mode). Note that in upcoming top
boot versions of this device, the ESN will be located
in sector 70 at addresses 3FFF00h-3FFF0Fh in byte
mode (or 1FFF80h-1FFF87h in word mode).
Security Lock-Indicator Bit (DQ7)
In the device, the security sector can be provided in
either factory locked version or customer lockable
version. The
factory-locked version
is always pro-
tected when shipped from the factory, and has the
security lock-indicator bit permanently set to a “1”.
The
customer-lockable version
is shipped with
the security sector unprotected, allowing customers
to utilize the sector in any manner they choose. The
customer-lockable version has the security lock-
indicator bit permanently set to a “0”. Thus, the
security lock-Indicator bit prevents customer-lock-
ble devices from being used to replace devices that
are factory locked.
ESI’s Special-Code Service
Customers may opt to have their code programmed
by ESI through the ESI’s Special-Code service. ESI
programs the customer’s code, with or without the
random ESN. The devices are then shipped from
ESI’s factory with the Security Sector permanently
locked. Contact an ESI representative for details on
using ESI’s Special-Code service.
Customer-Lockable Device
The customer lockable version allows the security
sector to be freely programmed or erased and then
permanently locked. Note that the ES29DL320 has
a security sector size of 256 bytes (128 words). Note
that the accelerated programming (ACC) and unlock
bypass functions are not available when program-
ming the security sector.
Access to the Security Sector
The security sector can be accessed through a
command sequence:
Enter security
and
Exit
security
sector commands. After the system has
written the Enter security sector command
sequence, it may read the security sector by using
the addresses normally occupied by the boot sec-
tors. This mode of operation continues until the sys-
tem issues the exit security sector command
sequence, or until power is removed from the
device. On power-up, or following a hardware reset,
the device returns to read mode in which the nor-
mal boot sectors can be accessed, instead of the
security sector.
Protection of the Security Sector
The security sector area can be protected using the
following procedures: Write the three-cycle
“Enter
security sector command”
sequence, and then fol-
lowing the in-system sector protect algorithm as
shown in Fig. 2, except that RESET# may be at
either V
IH
or V
ID
. This allows
in-system protection
of the security sector without raising any device pin
to a high voltage. Note that this method is only appli-
cable to the security sector. To verify the protect/
unprotect status of the security sector. follow the
algorithm shown in Fig. 2.
Factory-Locked Device
In a factory-locked device, the security sector is
protected when the device is shipped from the fac-
tory. The security sector cannot be modified in any
way. The device is available preprogrammed with
one of the following:
ES29DL320
10
Rev. 0E May 25, 2006
EXCELSEMI [ EXCEL SEMICONDUCTOR INC. ]
