AT45DB642 datasheet(9/37 Pages) ATMEL

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AT45DB642

1638F–DFLSH–09/02

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. To initiate the operation, a 1-byte opcode, 60H for

buffer 1 and 61H for buffer 2, must be clocked into the device, followed by three address bytes

consisting of 13 page address bits (PA12 - PA0) that specify the page in the main memory that

is to be compared to the buffer, and 11 don’t carebits. TheCS pin must be low while toggling

the SCK/CLK pin to load the opcode and the address bytes from the input pins (SI or I/O7 -

I/O0). On the low-to-high transition of the CS pin, the 1056 bytes in the selected main memory

page will be compared with the 1056 bytes in buffer 1 or buffer 2. During this time (tXFR), the

status register and the RDY/BUSY pin will indicate that the part is busy. On completion of the

compare operation, bit 6 of the status register is updated with the result of the compare.

AUTO PAGE REWRITE: This mode is only needed if multiple bytes within a page or multiple

pages of data are modified in a random fashion. This mode is a combination of two operations:

Main Memory Page to Buffer Transfer and Buffer to Main Memory Page Program with Built-in

Erase. 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 its original page of

main memory. To start the rewrite operation, 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 13

page address bits (PA12 - PA0) that specify the page in main memory to be rewritten and 11

don’t care bits. When a low-to-high transition occurs on the CS pin, the part will first transfer

data from the page in main memory to a buffer and then program the data from the buffer back

into same page of main memory. The operation is internally self-timed and should take place

in a maximum time of tEP. During this time, the status register and the RDY/BUSY pin will indi-

cate that the part is busy.

If a sector is programmed or reprogrammed sequentially page by page, then the programming

algorithm shown in Figure 1 (page 33) is recommended. Otherwise, if multiple bytes in a page

or several pages are programmed randomly in a sector, then the programming algorithm

shown in Figure 2 (page 34) is recomm ended. Each page within a sector m ust be

updated/rewritten at least once within every 10,000 cumulative page erase/program opera-

tions in that sector.

Operation Mode

Summary

The modes described can be separated into two groups – modes that make use of the Flash

memory array (Group A) and modes that do not make use of the Flash memory array

(Group B).

Group A modes consist of:

Main Memory Page to Buffer 1 (or 2) Transfer

Main Memory Page to Buffer 1 (or 2) Compare

Buffer 1 (or 2) to Main Memory Page Program with Built-in Erase

Buffer 1 (or 2) to Main Memory Page Program without Built-in Erase

Page Erase

Block Erase

Main Memory Page Program through Buffer

Auto Page Rewrite

Group B modes consist of:

10. Buffer 1 (or 2) Read

11. Buffer 1 (or 2) Write

12. Status Register Read

If a Group A mode is in progress (not fully completed), then another mode in Group A should

not be started. However, during this time in which a Group A mode is in progress, modes in

Group B can be started.

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