AT49F040-55PI Atmel, AT49F040-55PI Datasheet - Page 3

• Manufacturer Part Number: AT49F040-55PI
• Manufacturer: Atmel

Specifications of AT49F040-55PI

• Cell Type: NOR
• Density: 4Mb
• Access Time (max): 55ns
• Interface Type: Parallel
• Boot Type: Bottom
• Address Bus: 19b
• Operating Supply Voltage (typ): 5V
• Operating Temp Range: -40C to 85C
• Package Type: PDIP
• Program/erase Volt (typ): 4.5 to 5.5V
• Sync/async: Asynchronous
• Operating Temperature Classification: Industrial
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (max): 5.5V
• Word Size: 8b
• Number Of Words: 512K
• Supply Current: 50mA
• Mounting: Through Hole
• Pin Count: 32
• Lead Free Status / Rohs Status: Not Compliant

Once the feature is enabled, the data in the boot block can
no longer be erased or programmed. Data in the main
memory block can still be changed through the regular pro-
gramming method. To activate the lockout feature, a series
of six program commands to specific addresses with spe-
cific data must be performed. Please refer to the Command
Definitions table.
BOOT BLOCK LOCKOUT DETECTION: A software
method is available to determine if programming of the boot
block section is locked out. When the device is in the soft-
ware product identification mode (see Software Product
Identification Entry and Exit sections) a read from address
location 00002H will show if programming the boot block is
locked out. If the data on I/O0 is low, the boot block can be
programmed; if the data on I/O0 is high, the program lock-
out feature has been activated and the block cannot be
programmed. The software product identification code
should be used to return to standard operation.
PRODUCT IDENTIFICATION: The product identification
mode identifies the device and manufacturer as Atmel. It
may be accessed by hardware or software operation. The
hardware operation mode can be used by an external pro-
grammer to identify the correct programming algorithm for
the Atmel product.
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: The AT49F040 features DATA 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 pro-
gram 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: In addition to DATA polling the AT49F040
provides another method for determining the end of a pro-
gram 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.
HARDWARE DATA PROTECTION: Hardware features
protect against inadvertent programs to the AT49F040 in
the following ways: (a) V
ical), the program function is inhibited. (b) Program inhibit:
holding any one of OE low, CE high or WE high inhibits
program cycles. (c) Noise filter: pulses of less than 15 ns
(typical) on the WE or CE inputs will not initiate a
program cycle.
AT49F040
CC
sense: if V
CC
is below 3.8V (typ-
3