P r e l i m i n a r y
I n f o r m a t i o n
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. If a read
is needed from the SecSi Sector area (One Time Program area) after an erase
suspend, then the user must use the proper command sequence to enter and exit
this region.
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 de-
vice.
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 V
CC
detector that automat-
ically inhibits write operations during power transitions. The device also offers
two types of data protection at the sector level. When at V
IL
,
WP#
locks the four
highest and four lowest boot sectors.
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.
The device electrically erases all bits within a sector simultaneously via Fowler-
Nordheim tunnelling. The data is programmed using hot electron injection.
4
Am29BDS128H/Am29BDS064H
27024_A5_00_E June 18, 2004
SPANSION [ SPANSION ]
