7

AT49BV802A(T)

3405C–FLASH–9/04

RDY/BUSY: An open-drain READY/BUSY output pin provides another method of detecting

the end of a program or erase operation. RDY/BUSY is actively pulled low during the internal

program and erase cycles and is released at the completion of the cycle. The open-drain con-

nection allows for OR-tying of several devices to the same RDY/BUSY line. Please see

“Status Bit Table” on page 10 for more details.

CFI: Common Flash Interface (CFI) is a published, standardized data structure that may be

read from a flash device. CFI allows system software to query the installed device to deter-

mine the configurations, various electrical and timing parameters, and functions supported by

the device. CFI is used to allow the system to learn how to interface to the flash device most

optimally. The two primary benefits of using CFI are ease of upgrading and second source

availability. The command to enter the CFI Query mode is a one-bus cycle command which

requires writing data 98h to address 55h. The CFI Query command can be written when the

device is ready to read data or can also be written when the part is in the product ID mode.

Once in the CFI Query mode, the system can read CFI data at the addresses given in Table 1

on page 23. To exit the CFI Query mode, the product ID exit command must be given.

HARDWARE DATA PROTECTION: The Hardware Data Protection feature protects against

inadvertent programs to the AT49BV802A(T) in the following ways: (a) V

below 1.8V (typical), the program function is inhibited. (b) V

reached the V

gramming. (c) Program inhibit: holding any one of OE low, CE high or WE high inhibits

program cycles.

INPUT LEVELS: While operating with a 2.65V to 3.6V power supply, the address inputs and

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

operation of the device. The I/O lines can only be driven from 0 to V