D a t a
S h e e t
the first sector (SA0). This mode of operation continues until the system issues the Exit Se-
cured Silicon Sector command sequence, or until power is removed from the device. On
power-up, or following a hardware reset, the device reverts to sending commands to sector
SA0.
Customer Lockable: Secured Silicon Sector NOT Programmed or
Protected At the Factory
Unless otherwise specified, the device is shipped such that the customer may program and
protect the 256-byte Secured Silicon sector.
The system may program the Secured Silicon Sector using the write-buffer, accelerated
and/or unlock bypass methods, in addition to the standard programming command sequence.
See
Programming and protecting 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.
To verify the protect/unprotect status of the Secured Silicon Sector, follow the algorithm.
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
within the remainder of the array.
Factory Locked: Secured Silicon Sector Programmed and
Protected At the Factory
In devices 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. An ESN Factory
Locked device has an 16-byte random ESN at addresses 000000h–000007h. Please contact
your sales representative for details on ordering ESN Factory Locked devices.
Customers may opt to have their code programmed by the factory through the ExpressFlash
service (Express Flash Factory Locked). The devices are then shipped from the factory with
the Secured Silicon Sector permanently locked. Contact your sales representative for details
on using the ExpressFlash service.
Write Protect (WP#)
The Write Protect function provides a hardware method of protecting the first or last sector
group without using V
ID
. Write Protect is one of two functions provided by the WP#/ACC
input.
If the system asserts V
IL
on the WP#/ACC pin, the device disables program and erase func-
tions in the first or last sector group independently of whether those sector groups were
protected or unprotected using the method described in
Note that if WP#/ACC is at V
IL
when the device is in the standby mode, the maxi-
mum input load current is increased. See the table in
If the system asserts V
IH
on the WP#/ACC pin, the device reverts to whether the
first or last sector was previously set to be protected or unprotected. Note that WP#
has an internal pullup; when unconnected, WP# is at V
IH
.
44
S29GL-N MirrorBit™ Flash Family
S29GL-N_00_B3 October 13, 2006
SPANSION [ SPANSION ]
