AT45DB021D-MU datasheet(23/52 Pages) ATMEL

23 / 52 page

3638B–DFLASH–02/07

AT45DB021D [Preliminary]

data in the buffer. If bit 6 is a 1, then at least one bit of the data in the main memory page does

not match the data in the buffer.

Bit 1 in the Status Register is used to provide information to the user whether or not the sector

protection has been enabled or disabled, either by software-controlled method or hardware-con-

trolled method. A logic 1 indicates that sector protection has been enabled and logic 0 indicates

that sector protection has been disabled.

Bit 0 in the Status Register indicates whether the page size of the main memory array is config-

ured for “power of 2” binary page size (256 bytes) or the DataFlash standard page size

(264 bytes). If bit 0 is a 1, then the page size is set to 256 bytes. If bit 0 is a 0, then the page size

is set to 264 bytes.

The device density is indicated using bits 5, 4, 3, and 2 of the status register. For the

AT45DB021D, the four bits are 0111 The decimal value of these four binary bits does not equate

to the device density; the four bits represent a combinational code relating to differing densities

of DataFlash devices. The device density is not the same as the density code indicated in the

JEDEC device ID information. The device density is provided only for backward compatibility.

Table 11-1.

Status Register Format

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

RDY/BUSY

COMP

PROTECT

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