AT45DB021E datasheet(37/69 Pages) RENESAS

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DS-AT45DB021E-8789 Rev. N

Page 37

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AT45DB021E Datasheet

14. Manufacturer and Device ID Read

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

device while it is in the 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 fCLK. Since not all

Flash devices are capable of operating at very high clock frequencies, applications must 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 then the opcode 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 to be output is the Manufacturer ID, followed by two

bytes of the Device ID information. The fourth byte output is the Extended Device Information (EDI) String Length,

which is 01h, indicating that one byte of EDI data follows. After the one byte of EDI data is output, the SO pin goes

into a high-impedance state; therefore, additional clock cycles have no affect on the SO pin and no data are

output. As indicated in the JEDEC Standard, reading the EDI 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 22. Manufacturer and Device ID Information

Byte No.

Data Type

Value

Manufacturer ID

1Fh

Device ID (Byte 1)

23h

Device ID (Byte 2)

00h

Extended Device Information (EDI) String Length

01h

[Optional to Read] EDI Byte 1

00h

Table 23. 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)

111

Device ID (Byte 1)

Family Code

Density Code

23h

Family code: 001 (AT45Dxxx Family)

Density code: 00011 (2-Mbit)

000

Device ID (Byte 2)

Sub Code

Product Variant

00h

Sub code: 000 (Standard Series)

Product variant: 00000

000

Table 24. EDI Data

Byte

Number

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Hex

Value

Details

RFU

Device Revision

00h

RFU: Reserved for Future Use

Device revision: 00000 (Initial Version)

000

0000

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