AT25DF321A-MH-T datasheet(37/52 Pages) ATMEL

37 / 52 page

3686D–DFLASH–12/09

Atmel AT25DF321A

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 specific Device ID,

and the vendor specific Extended Device Information.

The Read Manufacturer and Device ID command is limited to a maximum clock frequency of f

CLK. 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)

47h

Device ID (Part 2)

01h

Extended Device Information String Length

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 Atmel)

00011111

Device ID (Part 1)

Family Code

Density Code

47h

Family Code:

010 (AT25DF/26DFxxx series)

Density Code: 00111 (32-Mbit)

01000111

Device ID (Part 2)

Sub Code

Product Version Code

01h

Sub Code:

000 (Standard series)

Product Version:00001 (First major revision)

00000001

AT25DF321A-MH-T Datenblatt(PDF) 37 Page - ATMEL Corporation

AT25DF321A-MH-T Datenblatt(HTML) 37 Page - ATMEL Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

Datenblatt Download

Link URL