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AT49BV/LV2048A

1914D–FLASH–03/02

PRODUCT IDENTIFICATION: The product identification mode identifies the device and man-

ufacturer as Atmel. It may be accessed by hardware or software operation. The hardware

operation mode can be used by an external programmer to identify the correct programming

algorithm for the Atmel product.

For details, see “Operating Modes” (for hardware operation) or “Software Product Identifica-

tion Entry/Exit” on page 13. The manufacturer and device codes are the same for both modes.

DATA POLLING: The AT49BV/LV2048A 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 completed, true

data is valid on all outputs and the next cycle may begin. During a chip or sector erase opera-

tion, an attempt to read the device will give a “0” on I/O7. Once the program or erase cycle has

completed, true data will be read from the device. Data Polling may begin at any time during

the program cycle.

TOGGLE BIT: In addition to Data Polling, the AT49BV/LV2048A provides another method for

determining the end of a program or erase cycle. During a program or erase operation, suc-

cessive 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

sense level, the device will automatically time out 10 ms (typical) before programming. (c) Pro-

gram inhibit: holding any one of OE low, CE high or WE high inhibits program cycles. (d) Noise

filter: pulses of less than 15 ns (typical) on the WE or CE inputs will not initiate a program

cycle.

INPUT LEVELS: While operating with a 2.7V to 3.6V power supply, the address and control

inputs (OE,CE and WE) may be driven from 0 to 5.5V without adversely affecting the opera-