AT25DF041B datasheet(39/64 Pages) RENESAS

39 / 64 page

DS-AT25DF041B-040 Rev. H

Page 39

12/13/22

AT25DF041B Datasheet

12. Other Commands and Functions

12.1 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 specific

Device ID, and the vendor specific Extended Device Information.

Since not all Flash devices are capable of operating at very high clock frequencies, design applications to read the

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

application can be identified properly. Once the identification process is complete, the application can 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 begins outputting the identification data on the

SO pin during the subsequent clock cycles. The first byte output is the Manufacturer ID, followed by two bytes of

Device ID information. The fourth byte output is the Extended Device Information String Length, which is 00h

indicating that no Extended Device Information follows. After the Extended Device Information String Length byte

is output, the SO pin goes into a high-impedance state; thus, additional clock cycles have no affect on the SO pin,

and no data are output. As indicated in the JEDEC standard, reading the Extended Device Information String

Length and any subsequent data is optional. Deasserting the CS pin terminates 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 13. Manufacturer and Device ID Information

Byte No.

Data Type

Value

Manufacturer ID

1Fh

Device ID (Part 1)

44h

Device ID (Part 2)

02h

Extended Device Information String Length

00h

Table 14. 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 Renesas

Electronics)

0011

111

Device ID (Part 1)

Family Code

Density Code

44h

Family Code: 010 (AT25F/AT25DFxxx series)

Density Code: 00100 (4-Mbit)

1000

100

Device ID (Part 2)

Sub Code

Product Version Code

02h

Sub Code: 000 (Standard series)

Product Version: 00010

0000

010

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