S29GL-A SPANSION [SPANSION], S29GL-A Datasheet - Page 40

• Manufacturer Part Number: S29GL-A
• Description: S29GL-A MirrorBit Flash Family
• Manufacturer: SPANSION [SPANSION]

38
Write Protect (WP#)
Hardware Data Protection
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 or-
dering ESN Factory Locked devices.
Customers may opt to have their code programmed by the factory through the
Spansion programming service (Customer 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 Spansion program-
ming service.
The Write Protect function provides a hardware method of protecting the first or
last sector group without using V
vided by the WP#/ACC input.
If the system asserts V
erase functions in the first or last sector group independently of whether those
sector groups were protected or unprotected. Note that if WP#/ACC is at V
when the device is in the standby mode, the maximum input load current is in-
creased. See the table in
If the system asserts V
whether the first or last sector was previously set to be protected or un-
protected using the method described in
Unprotection on page
when unconnected, WP# is at V
The command sequence requirement of unlock cycles for programming or eras-
ing provides data protection against inadvertent writes (refer to
page 54
lowing hardware data protection measures prevent accidental erasure or
programming, which might otherwise be caused by spurious system level signals
during V
Low V
When V
protects data during V
Write the three-cycle Enter Secured Silicon Sector Region command se-
quence, and then follow the in-system sector protect algorithm as shown in
Figure 2, on page
allows in-system protection of the Secured Silicon Sector without raising any
device pin to a high voltage. Note that this method is only applicable to the
Secured Silicon Sector.
Write the three-cycle Enter Secured Silicon Sector Region command se-
quence, and then use the alternate method of sector protection described in
the
Sector Group Protection and Unprotection on page 31
CC
CC
CC
and
is less than V
Write Inhibit
power-up and power-down transitions, or from system noise.
Table 31 on page 55
36, except that RESET# may be at either V
CC
IL
LKO
power-up and power-down. The command register and
S29GL-A MirrorBit™ Flash Family
on the WP#/ACC pin, the device disables program and
31. Note that WP# contains an internal pullup;
DC Characteristics on page
IH
A d v a n c e
, the device does not accept any write cycles. This
on the WP#/ACC pin, the device reverts to
ID
for command definitions). In addition, the fol-
IH
. Write Protect is one of two functions pro-
.
I n f o r m a t i o n
Sector Group Protection and
64.
section.
IH
Table 30 on
or V
ID
. This
S29GL-A_00_A3 April 22, 2005
IL