18
MBM29LV002T/MBM29LV002B
RESET
Hardware Reset
The MBM29LV002T/002B devices may be reset by driving the RESET pin to V
requirement and has to be kept low (V
IL
) for at least 500 ns in order to properly reset the internal state machine.
Any operation in the process of being executed will be terminated and the internal state machine will be reset
to the read mode 20
μ
s after the RESET pin is driven low. Furthermore, once the RESET pin goes high, the
devices requires an additional 50 ns before it will allow read access. When the RESET pin is low, the device will
be in the standby mode for the duration of the pulse and all the data output pins will be tri-stated. If a hardware
reset occurs during a program or erase operation, the data at that particular location will be corrupted. Please
note that the RY/BY output signal should be ignored during the RESET pulse. See Figure 10 for the timing
diagram. Refer to Temporary Sector Unprotection for additional functionality.
IL
. The RESET pin has a pulse
If hardware reset occurs during Embedded Erase Algorithm, there is a possibility that the erasing sector(s)
cannot be used.
Data Protection
The MBM29LV002T/002B are designed to offer protection against accidental erasure or programming caused
by spurious system level signals that may exist during power transitions. During power up the device automatically
resets the internal state machine in the Read mode. Also, with its control register architecture, alteration of the
memory contents only occurs after successful completion of specific multi-bus cycle command sequences.
The devices also incorporates several features to prevent inadvertent write cycles resulting form V
and power-down transitions or system noise.
CC
power-up
Low V
CC
Write Inhibit
To avoid initiation of a write cycle during V
than 2.5 V (typically 2.4 V). If V
are disabled. Under this condition the device will reset to the Read mode. Subsequent writes will be ignored
until the V
CC
level is greater than V
LKO
. It is the users responsibility to ensure that the control pins are logically
correct to prevent unintentional writes when V
CC
is above 2.5 V.
CC
power-up and power-down, a write cycle is locked out for V
, the command register is disabled and all internal program/erase circuits
CC
less
CC
< V
LKO
If Embedded Erase Algorithm is interrupted, there is possibility that the erasing sector(s) cannot be used.
Write Pulse “Glitch” Protection
Noise pulses of less than 5 ns (typical) on OE, CE, or WE will not initiate a write cycle.
Logical Inhibit
Writing is inhibited by holding any one of OE = V
must be a logical zero while OE is a logical one.
IL
, CE = V
IH
, or WE = V
IH
. To initiate a write cycle CE and WE
Power-Up Write Inhibit
Power-up of the device with WE = CE = V
The internal state machine is automatically reset to the read mode on power-up.
IL
and OE = V
IH
will not accept commands on the rising edge of WE.