AT25DF081A datasheet(38/54 Pages) ETC2

38 / 54 page

8715C–SFLSH–1/2013

AT25DF081A

12.2 Read Manufacturer and Device ID

Identification information can be read from the device to enable systems to electronically query and identify the

device while it is in system. The identification method and the command opcode comply with the JEDEC standard

for “Manufacturer and Device ID Read Methodology for SPI Compatible Serial Interface Memory Devices”. The

type of information that can be read from the device includes the JEDEC defined Manufacturer ID, the vendor spe-

cific Device ID, and the vendor specific Extended Device Information.

The Read Manufacturer and Device ID command is limited to a maximum clock frequency of fCLK. Since not all

Flash devices are capable of operating at very high clock frequencies, applications should be designed to read the

identification information from the devices at a reasonably low clock frequency to ensure that all devices to be used

in the application can be identified properly. Once the identification process is complete, the application can then

increase the clock frequency to accommodate specific Flash devices that are capable of operating at the higher

clock frequencies.

To read the identification information, the CS pin must first be asserted and the opcode of 9Fh must be clocked into

the device. After the opcode has been clocked in, the device will begin outputting the identification data on the SO

pin during the subsequent clock cycles. The first byte that will be output will be the Manufacturer ID followed by two

bytes of Device ID information. The fourth byte output will be the Extended Device Information String Length, which

will be 00h indicating that no Extended Device Information follows. After the Extended Device Information String

Length byte is output, the SO pin will go into a high-impedance state; therefore, additional clock cycles will have no

affect on the SO pin and no data will be output. As indicated in the JEDEC standard, reading the Extended Device

Information String Length and any subsequent data is optional.

Deasserting the CS pin will terminate the Manufacturer and Device ID 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 12-1.

Manufacturer and Device ID Information

Byte No.

Data Type

Value

Manufacturer ID

1Fh

Device ID (Part 1)

45h

Device ID (Part 2)

01h

[Optional to read] Extended Device Information (EDI) String Length

01h

[Optional to read] EDI Byte 1

00h

Table 12-2.

Manufacturer and Device ID Details

Data Type

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Hex

Value

Details

Manufacturer ID

JEDEC Assigned Code

1Fh

JEDEC Code:

0001 1111 (1Fh for Adesto)

00011111

Device ID (Part 1)

Family Code

Density Code

45h

Family Code:

010 (AT25DF/26DFxxx series)

Density Code:

00101 (8-Mbit)

01000101

Device ID (Part 2)

Sub Code

Product Version Code

01h

Sub Code:

000 (Standard series)

Product Version: 00001 (Second major version)

00000001

AT25DF081A Datasheet(PDF) 38 Page - List of Unclassifed Manufacturers

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