AT45DB321E-DWF datasheet(38/80 Pages) RENESAS

38 / 80 page

DS-AT45DB321E-8784 Rev. N

Page 38

9/1/23

AT45DB321E Datasheet

Additional Commands

9.1

Main Memory Page to Buffer Transfer

A page of data can be transferred from the main memory to either Buffer 1 or Buffer 2. To transfer a page of data

using the standard DataFlash page size (528 bytes), an opcode of 53h for Buffer 1 or 55h for Buffer 2 must be

clocked into the device followed by three address bytes comprised of one dummy bit, 13 page address bits (PA12

- PA0) which specify the page in main memory to be transferred, and 10 dummy bits. To transfer a page of data

using the binary page size (512 bytes), an opcode of 53h for Buffer 1 and 55h for Buffer 2 must be clocked into the

device followed by three address bytes comprised of two dummy bits, 13 page address bits (A21 - A9) which

specify the page in the main memory to be transferred, and nine dummy bits.

The CS pin must be low while toggling the SCK pin to load the opcode and the three address bytes from the input

pin (SI). The transfer of the page of data from the main memory to the buffer begins when the CS pin transitions

from a low to a high state. During the page transfer time (tXFR), the RDY/BUSY bit in the Status Register can be

read to determine whether or not the transfer has been completed.

9.2

Main Memory Page to Buffer Compare

A page of data in main memory can be compared to the data in Buffer 1 or Buffer 2 as a method to ensure that

data was successfully programmed after a Buffer to Main Memory Page Program command. To compare a page

of data with the standard DataFlash page size (528 bytes), an opcode of 60h for Buffer 1 or 61h for Buffer 2 must

be clocked into the device followed by three address bytes comprised of one dummy bit, 13 page address bits

(PA12 - PA0) which specify the page in the main memory to be compared to the buffer, and 10 dummy bits. To

compare a page of data with the binary page size (512 bytes), an opcode of 60h for Buffer 1 or 61h for Buffer 2

must be clocked into the device followed by three address bytes comprised of two dummy bits, 13 page address

bits (A21 - A9) which specify the page in the main memory to be compared to the buffer, and nine dummy bits.

The CS pin must be low while toggling the SCK pin to load the opcode and the address bytes from the input pin

(SI). On the low-to-high transition of the CS pin, the data bytes in the selected Main Memory Page are compared

with the data bytes in Buffer 1 or Buffer 2. During the compare time (tCOMP), the RDY/BUSY bit in the Status

updated with the result of the compare.

9.3

Auto Page Rewrite

This command only needs to be used if the possibility exists that static (non-changing) data can be stored in a

page or pages of a sector and the other pages of the same sector are erased and programmed a large number of

times. Applications that modify data in a random fashion within a sector can fall into this category. To preserve

data integrity of a sector, each page within a sector must be updated/rewritten at least once within every 50,000

cumulative page erase/program operations within that sector. The Auto Page Rewrite command provides a simple

and efficient method to “refresh” a page in the main memory array in a single operation.

The Auto Page Rewrite command is a combination of the Main Memory Page to Buffer Transfer and Buffer to

Main Memory Page Program with Built-In Erase commands. With the Auto Page Rewrite command, a page of

data is first transferred from the main memory to Buffer 1 or Buffer 2 and then the same data (from Buffer 1 or

Buffer 2) is programmed back into the same page of main memory, essentially “refreshing” the contents of that

page. To start the Auto Page Rewrite operation with the standard DataFlash page size (528 bytes), a 1-byte

opcode, 58H for Buffer 1 or 59H for Buffer 2, must be clocked into the device followed by three address bytes

comprised of one dummy bit, 13 page address bits (PA12-PA0) that specify the page in main memory to be

rewritten, and 10 dummy bits.

To initiate an Auto Page Rewrite with the a binary page size (512 bytes), the opcode 58H for Buffer 1 or 59H for

Buffer 2, must be clocked into the device followed by three address bytes consisting of two dummy bits, 13 page

address bits (A21 - A9) that specify the page in the main memory that is to be rewritten, and nine dummy bits.

When a low-to-high transition occurs on the CS pin, the part first transfers data from the page in main memory to

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