9

3626A–FLASH–2/07

AT49BV802D(T)

4.13

Common Flash Interface (CFI)

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 determine 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 31. on page 25. To exit the CFI Query mode, the product ID

exit command must be given.

4.14

Hardware Data Protection

The Hardware Data Protection feature protects against inadvertent programs to the

AT49BV802D(T) in the following ways: (a) V

function is inhibited. (b) V

device will automatically time out 10 ms (typical) before programming. (c) Program inhibit: hold-

ing any one of OE low, CE high or WE high inhibits program cycles.

4.15

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