P r e l i m i n a r y
Write cycles also internally latch addresses and data needed for the programming
and erase operations. Reading data out of the device is similar to reading from
other Flash or EPROM devices.
The Erase Suspend/Erase Resume feature enables the user to put erase on
hold for any period of time to read data from, or program data to, any sector that
is not selected for erasure. True background erase can thus be achieved.
The hardware RESET# pin terminates any operation in progress and resets the
internal state machine to reading array data. The RESET# pin may be tied to the
system reset circuitry. A system reset would thus also reset the device, enabling
the system microprocessor to read boot-up firmware from the Flash memory
device.
The host system can detect whether a program or erase operation is complete by
using the device status bit DQ7 (Data# Polling) and DQ6/DQ2 (toggle bits). After
a program or erase cycle has been completed, the device automatically returns
to reading array data.
The sector erase architecture allows memory sectors to be erased and repro-
grammed without affecting the data contents of other sectors. The device is fully
erased when shipped from the factory.
Hardware data protection measures include a low VCC detector that automat-
ically inhibits write operations during power transitions. The device also offers
two types of data protection at the sector level. The sector lock/unlock com-
mand sequence disables or re-enables both program and erase operations in
any sector. When at VIL, WP# locks sectors 0 and 1 (bottom boot device) or sec-
tors 68 and 69 (top boot device).
The device offers two power-saving features. When addresses have been stable
for a specified amount of time, the device enters the automatic sleep mode.
The system can also place the device into the standby mode. Power consump-
tion is greatly reduced in both modes.
Spansion flash technology combines years of flash memory manufacturing expe-
rience to produce the highest levels of quality, reliability and cost effectiveness.
The device electrically erases all bits within a sector simultaneously via Fowler-
Nordheim tunnelling. The data is programmed using hot electron injection.
October 1, 2003 27243B1
Am29BDS320G
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SPANSION [ SPANSION ]
