4 Mbit SPI Serial Flash
SST25VF040B
Data Sheet
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 multi-
ple 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 bits
[A23-A0]. Following the Read-ID instruction, the manufac-
turer’s ID is located in address 00000H and the device ID is
located in address 00001H. Once the device is in Read-ID
mode, the manufacturer’s and device ID output data tog-
gles between address 00000H and 00001H until termi-
nated by a low to high transition on CE#.
Refer to Tables 6 and 7 for device identification data.
CE#
MODE 3
MODE 0
0
1
2
3
4
5
6
7
8
15 16
23
31
39
40
47 48
55 56
63
24
32
SCK
90 or AB
00
00
ADD1
MSB
SI
MSB
HIGH
IMPEDANCE
HIGH IMPEDANCE
Device ID
Device ID
BF
BF
SO
MSB
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.
1295 RdID.0
FIGURE 21: Read-ID Sequence
TABLE 7: Product Identification
Address
Data
Manufacturer’s ID
Device ID
00000H
BFH
SST25VF040B
00001H
8DH
T7.0 1295
©2009 Silicon Storage Technology, Inc.
S71295-05-000
10/09
21
SST [ SILICON STORAGE TECHNOLOGY, INC ]
