AT29BV040A-25 ATMEL Corporation, AT29BV040A-25 Datasheet - Page 3

• Manufacturer Part Number: AT29BV040A-25
• Description: 4 Megabit 512K x 8 Single 2.7-volt Battery-Voltage CMOS Flash Memory
• Manufacturer: ATMEL Corporation

Absolute Maximum Ratings*
Device Operation (Continued)
PRODUCT IDENTIFICATION: The product identifica-
tion mode identifies the device and manufacturer as At-
mel. It may be accessed by hardware or software opera-
tion. The hardware operation mode can be used by an ex-
ternal programmer to identify the correct programming al-
gorithm for the Atmel product. In addition, users may wish
to use the software product identification mode to identify
the part (i.e. using the device code), and have the system
software use the appropriate sector size for program op-
erations. In this manner, the user can have a common
board design for 256K to 4-megabit densities and, with
each density’s sector size in a memory map, have the sys-
tem software apply the appropriate sector size.
For details, see Operating Modes (for hardware operation)
or Software Product Identification. The manufacturer and
device code is the same for both modes.
DATA POLLING:
polling to indicate the end of a program cycle. During a
program cycle an attempted read of the last byte loaded
will result in the complement of the loaded data on I/O7.
Once the program cycle has been completed, true data is
valid on all outputs and the next cycle may begin. DATA
polling may begin at any time during the program cycle.
TOGGLE BIT:
AT29BV040A provides another method for determining
the end of a program or erase cycle. During a program or
erase operation, successive attempts to read data from
the device will result in I/O6 toggling between one and
zero. Once the program cycle has completed, I/O6 will
stop toggling and valid data will be read. Examining the
toggle bit may begin at any time during a program cycle.
OPTIONAL CHIP ERASE MODES: The entire device
may be erased by using a 6-byte software code. Please
see Software Chip Erase application note for details.
Temperature Under Bias................. -55°C to +125°C
Storage Temperature ...................... -65°C to +150°C
All Input Voltages
(including NC Pins)
with Respect to Ground.................... -0.6V to +6.25V
All Output Voltages
with Respect to Ground..............-0.6V to V
Voltage on A9
(including NC Pins)
with Respect to Ground.................... -0.6V to +13.5V
I n a d d i t i o n t o DATA p o l l i n g t h e
The AT29BV040A features DATA
CC
+ 0.6V
*NOTICE: Stresses beyond those listed under “Absolute Maxi-
BOOT BLOCK PROGRAMMING LOCKOUT: The
AT29BV040A has two designated memory blocks that
have a programming lockout feature. This feature pre-
vents programming of data in the designated block once
the feature has been enabled. Each of these blocks con-
sists of 16K bytes; the programming lockout feature can
be set independently for either block. While the lockout
feature does not have to be activated, it can be activated
for either or both blocks.
These two 16K memory sections are referred to as boot
blocks . Secure code which will bring up a system can be
contained in a boot block. The AT29BV040A blocks are
located in the first 16K bytes of memory and the last 16K
bytes of memory. The boot block programming lockout
feature can therefore support systems that boot from the
lower addresses of memory or the higher addresses.
Once the programming lockout feature has been acti-
vated, the data in that block can no longer be erased or
programmed; data in other memory locations can still be
changed through the regular programming methods. To
activate the lockout feature, a series of seven program
commands to specific addresses with specific data must
be performed. Please see Boot Block Lockout Feature En-
able Algorithm.
If the boot block lockout feature has been activated on
either block, the chip erase function will be disabled.
BOOT BLOCK LOCKOUT DETECTION: A software
method is available to determine whether programming of
either boot block section is locked out. See Software Prod-
uct Identification Entry and Exit sections. When the device
is in the software product identification mode, a read from
location 00002H will show if programming the lower ad-
dress boot block is locked out while reading location
FFFF2H will do so for the upper boot block. If the data is
FE, the corresponding block can be programmed; if the
data is FF, the program lockout feature has been activated
and the corresponding block cannot be programmed. The
software product identification exit mode should be used
to return to standard operation.
mum Ratings” may cause permanent damage to the device.
This is a stress rating only and functional operation of the
device at these or any other conditions beyond those indi-
cated in the operational sections of this specification is not
implied. Exposure to absolute maximum rating conditions
for extended periods may affect device reliability.
AT29BV040A
4-25