MX29LV640BT/BB
REQUIREMENTS FOR READING ARRAY
DATA
ACCELERATED PROGRAM OPERATION
The device offers accelerated program operations through
the ACC function. This is one of two functions provided
by the WP#/ACC pin.This function is primarily intended
to allow faster manufacturing throughput at the factory.
To read array data from the outputs, the system must
drive the CE# and OE# pins to VIL. CE# is the power
control and selects the device. OE# is the output control
and gates array data to the output pins.WE# should re-
main at VIH.
If the system asserts VHH on this pin, the device auto-
matically enters the aforementioned accelerated program
mode, temporarily unprotects any protected sectors, and
uses the higher voltage on the pin to reduce the time
required for program operations. RemovingVHH from the
WP#/ACC pin must not be at VHH for operations other
than accelerated programming, or device damage may
result.
The internal state machine is set for reading array data
upon device power-up, or after a hardware reset. This
ensures that no spurious alteration of the memory con-
tent occurs during the power transition. No command is
necessary in this mode to obtain array data. Standard
microprocessor read cycles that assert valid address on
the device address inputs produce valid data on the de-
vice data outputs. The device remains enabled for read
access until the command register contents are altered.
STANDBY MODE
MX29LV640BT/BB can be set into Standby mode with
two different approaches. One is using both CE# and
RESET# pins and the other one is using RESET# pin
only.
WRITE COMMANDS/COMMAND SEQUENCES
To program data to the device or erase sectors of memory
, the system must drive WE# and CE# to VIL, and OE#
to VIH.
When using both pins of CE# and RESET#, a CMOS
Standby mode is achieved with both pins held at Vcc ±
0.3V. Under this condition, the current consumed is less
than 0.2uA (typ.). If both of the CE# and RESET# are
held at VIH, but not within the range of VCC ±0.3V, the
device will still be in the standby mode, but the standby
current will be larger. During Auto Algorithm operation,
Vcc active current (Icc2) is required even CE# = "H"
until the operation is completed.The device can be read
with standard access time (tCE) from either of these
standby modes.
An erase operation can erase one sector, multiple sec-
tors , or the entire device. Table indicates the address
space that each sector occupies. A "sector address"
consists of the address bits required to uniquely select a
sector.The "Writing specific address and data commands
or sequences into the command register initiates device
operations. Table 1 defines the valid register command
sequences.Writing incorrect address and data values or
writing them in the improper sequence resets the device
to reading array data. Section has details on erasing a
sector or the entire chip, or suspending/resuming the erase
operation.
When using only RESET#, a CMOS standby mode is
achieved with RESET# input held at Vss ±0.3V, Under
this condition the current is consumed less than 1uA
(typ.). Once the RESET# pin is taken high, the device is
back to active without recovery delay.
After the system writes the Automatic Select command
sequence, the device enters the Automatic Select mode.
The system can then read Automatic Select codes from
the internal register (which is separate from the memory
array) on Q7-Q0. Standard read cycle timings apply in
this mode. Refer to the Automatic Select Mode and Au-
tomatic Select Command Sequence section for more
information.
In the standby mode the outputs are in the high imped-
ance state, independent of the OE# input.
MX29LV640BT/BB is capable to provide the Automatic
Standby Mode to restrain power consumption during read-
out of data. This mode can be used effectively with an
application requested low power consumption such as
handy terminals.
ICC2 in the DC Characteristics table represents the ac-
tive current specification for the write mode. The "AC
Characteristics" section contains timing specification
table and timing diagrams for write operations.
To active this mode, MX29LV640BT/BB automatically
P/N:PM1076
REV. 1.2, SEP. 07, 2005
16
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