at26f004 ATMEL Corporation, at26f004 Datasheet - Page 23

• Manufacturer Part Number: at26f004
• Description: At26f004 4-megabit 2.7-volt Only Serial Firmware Dataflash Memory
• Manufacturer: ATMEL Corporation

11. Other Commands and Functions
11.1
3588C–DFLASH–04/06
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 ven-
dor specific Extended Device Information.
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 out-
putting 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 11-1.
Byte No.
1
2
3
4
Manufacturer and Device ID Information
Data Type
Manufacturer ID
Device ID (Part 1)
Device ID (Part 2)
Extended Device Information String Length
AT26F004
Value
1FH
04H
00H
00H
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