D A T A S H E E T
at VHH for operations other than accelerated program- this mode when addresses remain stable for tACC
+
ming, or device damage may result. In addition, no ex-
ternal pullup is necessary since the WP#/ACC pin has
internal pullup to VCC.
30 ns. The automatic sleep mode is independent of
the CE#, WE#, and OE# control signals. Standard ad-
dress access timings provide new data when ad-
dresses are changed. While in sleep mode, output
data is latched and always available to the system.
Refer to the DC Characteristics table for the automatic
sleep mode current specification.
Autoselect Functions
If the system writes the autoselect command se-
quence, the device enters the autoselect mode. The
system can then read autoselect codes from the inter-
nal register (which is separate from the memory array)
on DQ7–DQ0. Standard read cycle timings apply in
this mode. Refer to the Autoselect Mode and Autose-
lect Command Sequence sections for more informa-
tion.
RESET#: Hardware Reset Pin
The RESET# pin provides a hardware method of re-
setting the device to reading array data. When the RE-
SET# pin is driven low for at least a period of tRP, the
device immediately terminates any operation in
progress, tristates all output pins, and ignores all
read/write commands for the duration of the RESET#
pulse. The device also resets the internal state ma-
chine to reading array data. The operation that was in-
terrupted should be reinitiated once the device is
ready to accept another command sequence, to en-
sure data integrity.
Standby Mode
When the system is not reading or writing to the de-
vice, it can place the device in the standby mode. In
this mode, current consumption is greatly reduced,
and the outputs are placed in the high impedance
state, independent of the OE# input.
Current is reduced for the duration of the RESET#
pulse. When RESET# is held at VSS 0.3 V, the device
draws CMOS standby current (ICC4). If RESET# is held
at VIL but not within VSS 0.3 V, the standby current will
be greater.
The device enters the CMOS standby mode when the
CE# and RESET# pins are both held at VIO 0.3 V.
(Note that this is a more restricted voltage range than
VIH.) If CE# and RESET# are held at VIH, but not within
VIO 0.3 V, the device will be in the standby mode, but
the standby current will be greater. The device re-
quires standard access time (tCE) for read access
when the device is in either of these standby modes,
before it is ready to read data.
The RESET# pin may be tied to the system reset cir-
cuitry. A system reset would thus also reset the Flash
memory, enabling the system to read the boot-up firm-
ware from the Flash memory.
If the device is deselected during erasure or program-
ming, the device draws active current until the
operation is completed.
Refer to the AC Characteristics tables for RESET# pa-
rameters and to Figure 16 for the timing diagram.
Output Disable Mode
When the OE# input is at VIH, output from the device is
disabled. The output pins are placed in the high
impedance state.
Refer to the DC Characteristics table for the standby
current specification.
Automatic Sleep Mode
The automatic sleep mode minimizes Flash device en-
ergy consumption. The device automatically enables
12
Am29LV640MH/L
December 14, 2005
SPANSION [ SPANSION ]
