SST25VF040B SST, SST25VF040B Datasheet - Page 4

• Manufacturer Part Number: SST25VF040B
• Description: 4 Mbit SPI Serial Flash
• Manufacturer: SST

Data Sheet
MEMORY ORGANIZATION
The SST25VF040B SuperFlash memory array is orga-
nized in uniform 4 KByte erasable sectors with 32 KByte
overlay blocks and 64 KByte overlay erasable blocks.
DEVICE OPERATION
The SST25VF040B is accessed through the SPI (Serial
Peripheral Interface) bus compatible protocol. The SPI bus
consist of four control lines; Chip Enable (CE#) is used to
©2006 Silicon Storage Technology, Inc.
FIGURE 2: SPI P
SCK
CE#
SO
SI
MODE 3
MODE 0
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
MSB
ROTOCOL
HIGH IMPEDANCE
4
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
MSB
select the device, and data is accessed through the Serial
Data Input (SI), Serial Data Output (SO), and Serial Clock
(SCK).
The SST25VF040B supports both Mode 0 (0,0) and Mode
3 (1,1) of SPI bus operations. The difference between the
two modes, as shown in Figure 2, is the state of the SCK
signal when the bus master is in Stand-by mode and no
data is being transferred. The SCK signal is low for Mode 0
and SCK signal is high for Mode 3. For both modes, the
Serial Data In (SI) is sampled at the rising edge of the SCK
clock signal and the Serial Data Output (SO) is driven after
the falling edge of the SCK clock signal.
DON'T CARE
4 Mbit SPI Serial Flash
MODE 3
MODE 0
SST25VF040B
1295 SPIprot.0
S71295-01-000
1/06