4

AT29C256

0046P–FLASH–10/04

PRODUCT IDENTIFICATION:

The product identification mode identifies the device

and manufacturer and may be accessed by a hardware operation. For details, see

Operating Modes or Product Identification.

DATA POLLING:

The AT29C256 features DATA polling to indicate the end of a pro-

gram 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 com-

pleted, 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 AT29C256 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 MODE:

The entire device can be erased by using a six-byte

software code. Please see Software Chip Erase application note for details.

Absolute Maximum Ratings*

Temperature Under Bias................................ -55

°C to +125°C

*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.

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