AT45DB641E datasheet(28/69 Pages) RENESAS

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AT45DB641E

DS-45DB641E-027N–DFLASH–2/2022

To initiate an Auto Page Rewrite with the a binary page size (256 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 1 dummy bit, 15 page address bits

(A22 - A8) that specify the page in the main memory that is to be rewritten, and 8 dummy 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 RDY/BUSY Status Register will indicate that the part is busy.

If a sector is programmed or reprogrammed sequentially page by page and the possibility does not exist that there will be

a page or pages of static data, then the programming algorithm shown in Figure 26-1 on page 61 is recommended.

Otherwise, if there is a chance that there may be a page or pages of a sector that will contain static data, then the

programming algorithm shown in Figure 26-2 on page 62 is recommended. Please contact Adesto for availability of

devices that are specified to exceed the 50,000 cycle cumulative limit.

Note:

The Auto Page Rewrite command uses the same opcodes as the Read-Modify-Write command. If data

bytes are clocked into the device, then the device will perform a Read-Modify-Write operation. See the

Read-Modify-Write command description on page 12 for more details.

9.4

Status Register Read

The 2-byte Status Register can be used to determine the device's ready/busy status, page size, a Main Memory Page to

Buffer Compare operation result, the sector protection status, Freeze Sector Lockdown status, erase/program error

status, Program/Erase Suspend status, and the device density. The Status Register can be read at any time, including

during an internally self-timed program or erase operation.

To read the Status Register, the CS pin must first be asserted and then the opcode D7h must be clocked into the device.

After the opcode has been clocked in, the device will begin outputting Status Register data on the SO pin during every

subsequent clock cycle. After the second byte of the Status Register has been clocked out, the sequence will repeat

itself, starting again with the first byte of the Status Register, as long as the CS pin remains asserted and the clock pin is

being pulsed. The data in the Status Register is constantly being updated, so each repeating sequence may output new

data. The RDY/BUSY status is available for both bytes of the Status Register and is updated for each byte.

Deasserting the CS pin will terminate the Status Register Read operation and put the SO pin into a high-impedance

state. The CS pin can be deasserted at any time and does not require that a full byte of data be read.

Table 9-1.

Status Register Format – Byte 1

Note:

1. R = Readable only

Bit

Name

Type

(1)

Description

RDY/BUSY

Ready/Busy Status

Device is busy with an internal operation.

Device is ready.

COMP

Compare Result

Main memory page data matches buffer data.

Main memory page data does not match buffer data.

5:2

DENSITY

Density Code

1111

64-Mbit

PROTECT

Sector Protection Status

Sector protection is disabled.

Sector protection is enabled.

PAGE SIZE

Page Size Configuration

Device is configured for standard DataFlash page size (264 bytes).

Device is configured for “power of 2” binary page size (256 bytes).

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