2-MBIT SmartVoltage BOOT BLOCK FAMILY
E
During erase or program modes, RP# low will abort
either erase or program operations, but the memory
contents are no longer valid as the data has been
corrupted by the RP# function. As in the read mode
above, all internal circuitry is turned off to achieve
the power savings.
3.5
Power Consumption
3.5.1
ACTIVE POWER
With CE# at a logic-low level and RP# at a logic-
high level, the device is placed in the active mode.
Refer to the DC Characteristics table for ICC current
values.
RP# transitions to VIL, or turning power off to the
device will clear the status register.
3.5.2
AUTOMATIC POWER SAVINGS (APS)
3.6
Power-Up/Down Operation
Automatic Power Savings (APS) provides low-
power operation during active mode. Power
Reduction Control (PRC) circuitry allows the device
to put itself into a low current state when not being
accessed. After data is read from the memory
array, PRC logic controls the device’s power
consumption by entering the APS mode where
typical ICC current is less than 1 mA. The device
stays in this static state with outputs valid until a
new location is read.
The device is protected against accidental block
erasure or programming during power transitions.
Power supply sequencing is not required, since the
device is indifferent as to which power supply, VPP
or VCC, powers-up first. The CUI is reset to the read
mode after power-up, but the system must drop
CE# low or present a new address to ensure valid
data at the outputs.
A system designer must guard against spurious
writes when VCC voltages are above VLKO and VPP
is active. Since both WE# and CE# must be low for
a command write, driving either signal to VIH will
inhibit writes to the device. The CUI architecture
provides additional protection since alteration of
memory contents can only occur after successful
completion of the two-step command sequences.
The device is also disabled until RP# is brought to
VIH, regardless of the state of its control inputs. By
holding the device in reset (RP# connected to
system PowerGood) during power-up/down, invalid
bus conditions during power-up can be masked,
providing yet another level of memory protection.
3.5.3
STANDBY POWER
With CE# at a logic-high level (VIH), and the CUI in
read mode, the memory is placed in standby mode,
which disables much of the device’s circuitry and
substantially reduces power consumption. Outputs
(DQ0–DQ15 or DQ0–DQ7) are placed in a high-
impedance state independent of the status of the
OE# signal. When CE# is at logic-high level during
erase or program operations, the device will
continue to perform the operation and consume
corresponding active power until the operation is
completed.
3.6.1
RP# CONNECTED TO SYSTEM
RESET
3.5.4
DEEP POWER-DOWN MODE
The use of RP# during system reset is important
with automated program/erase devices because the
system expects to read from the flash memory
when it comes out of reset. If a CPU reset occurs
The SmartVoltage boot block family supports a low
typical ICC in deep power-down mode, which turns
off all circuits to save power. This mode is activated
by the RP# pin when it is at a logic-low (GND ±
0.2 V).
without
a
flash memory reset, proper CPU
initialization would not occur because the flash
memory may be providing status information
instead of array data. Intel’s Flash memories allow
proper CPU initialization following a system reset
by connecting the RP# pin to the same RESET#
signal that resets the system CPU.
NOTE
Note: BYTE# pin must be at CMOS levels to
meet the ICCD specification.
During read modes, the RP# pin going low de-
selects the memory and places the output drivers in
a high impedance state. Recovery from the deep
power-down state, requires a minimum access time
of tPHQV (see AC Characteristics table).
26
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