AT29C040A-90TI Atmel, AT29C040A-90TI Datasheet - Page 5

• Manufacturer Part Number: AT29C040A-90TI
• Description: IC FLASH 4MBIT 90NS 32TSOP
• Manufacturer: Atmel

Specifications of AT29C040A-90TI

• Format - Memory: FLASH
• Memory Type: FLASH
• Memory Size: 4M (512K x 8)
• Speed: 90ns
• Interface: Parallel
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-TSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

4.9
4.10
4.10.1
5. Absolute Maximum Ratings*
0333L–FLASH–9/08
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 OE
with Respect to Ground ...................................-0.6V to +13.5V
Optional Chip Erase Mode
Boot Block Programming Lockout
Boot Block Lockout Detection
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.
The entire device can be erased by using a 6-byte software code. Please see Software Chip
Erase application note for details.
The AT29C040A has two designated memory blocks that have a programming lockout feature.
This feature prevents programming of data in the designated block once the feature has been
enabled. Each of these blocks consists 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 AT29C040A 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 activated, 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 Enable Algorithm.
If the boot block lockout feature has been activated on either block, the chip erase function will
be disabled.
A software method is available to determine whether programming of either boot block section is
locked out. See Software Product 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 address boot block is locked out while reading location 7FFF2H 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 pro-
grammed. The software product identification exit mode should be used to return to standard
operation.
CC
+ 0.6V
*NOTICE:
Stresses beyond those listed under “Absolute
Maximum Ratings” may cause permanent dam-
age to the device. This is a stress rating only and
functional operation of the device at these or any
other conditions beyond those indicated in the
operational sections of this specification is not
implied. Exposure to absolute maximum rating
conditions for extended periods may affect
device reliability.
AT29C040A
5