28F320D18
Product Preview
31
5.0
Data Protection
The 1.8 Volt Dual-Plane Flash memory architecture features dynamic hardware block-locking so
critical code can be kept secure while non-locked blocks are programmed or erased.
5.1
V
PP
≤
V
PPLK
for Complete Protection
The V
PP
programming voltage can be held low for complete write protection of all flash device
blocks. When V
PP
is below V
PPLK
, block erase or program operations result in an error in the
corresponding partition’s status register; bit (SR.3) is set.
5.2
WP# = V
IL
for Block Lock Down
Locked down blocks are securely or permanently locked down when WP# = V
IL
; any block erase
or program operation to a locked-down block will result in an error, which will be reflected in the
status register.
6.0
Program and Erase Voltages
Intel 1.8 Volt Dual-Plane Flash memory provides in-system programming and erase in the 1.8 V
range. For fast production programming, 1.8 Volt Dual-Plane Flash memory includes a low-cost,
backward-compatible high-performance Improved-12 V programming feature.
When V
PP
is between V
PP1
min and V
PP1
max, all program and erase current is drawn through the
V
CC
pin. Note that if V
PP
is driven by a logic signal, V
PP
must remain above V
PP1
min to perform
in-system flash modifications. When V
PP
is connected to a 12 V power supply, the device draws
program and erase current directly from the V
PP
pin. This eliminates the need for an external
switching transistor to control the V
PP
voltage.
Figure 13, “Example Power Supply Configurations” on page 34
, shows examples of how the flash
power supplies can be configured for various usage models.
6.1
Improved-12 V Programming Operation for Fast
Manufacturing
The 12 V V
PP
mode enhances programming performance during the short period of time typically
found in manufacturing processes; however, it is not intended for extended use. 12 V may be
applied to V
PP
during program and erase operations for a maximum of 1000 cycles on the main
blocks and 2500 cycles on the parameter blocks. V
PP
may be connected to 12 V for a total of 80
hours maximum. Stressing the device beyond these limits may cause permanent damage.