©2011 Silicon Storage Technology, Inc.

S71295-06-000

02/11

21

4 Mbit SPI Serial Flash

SST25VF040B

Data Sheet

A Microchip Technology Company

Read-ID (RDID)

The Read-ID instruction (RDID) identifies the devices as SST25VF040B and manufacturer as SST.

This command is backward compatible to all SST25xFxxxA devices and should be used as default

device identification when multiple versions of SPI Serial Flash devices are used in a design. The

device information can be read from executing an 8-bit command, 90H or ABH, followed by address

and the device ID is located in address 00001H. Once the device is in Read-ID mode, the manufac-

turer’s and device ID output data toggles between address 00000H and 00001H until terminated by a

low to high transition on CE#.

Refer to Tables 6 and 7 for device identification data.

Figure 21:Read-ID Sequence

Table 7: Product Identification

Address

Data

Manufacturer’s ID

00000H

BFH

Device ID

SST25VF040B

00001H

8DH

T7.0 1295

1295 RdID.0

CE#

SO

SI

SCK

00

01 2 3 4 5 6 7 8

00

90 or AB

HIGH IMPEDANCE

15 16

23 24

31 32

39 40

47 48

55 56

63

BF

Device ID

BF

Device ID

Note: The manufacturer s and device ID output stream is continuous until terminated by a low to high transition on CE#.

Device ID = 8DH for SST25VF040B

1. 00H will output the manfacturer s ID first and 01H will output device ID first before toggling between the two.

HIGH

IMPEDANCE

MODE 3

MODE 0

MSB

MSB

MSB