Datasheet

©2013 Silicon Storage Technology, Inc. DS20005054C 04/13
5
2 Mbit SPI Serial Flash
SST25VF020B
Data Sheet
Memory Organization
The SST25VF020B SuperFlash memory array is organized in uniform 4 KByte erasable sectors with 32
KByte overlay blocks and 64 KByte overlay erasable blocks.
Device Operation
The SST25VF020B 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 select the device, and data is
accessed through the Serial Data Input (SI), Serial Data Output (SO), and Serial Clock (SCK).
The SST25VF020B 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 3, 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.
Figure 3: SPI Protocol
1417 SPIprot.0
MODE 3
SCK
SI
SO
CE#
MODE 3
DON'T CARE
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
MODE 0MODE 0
HIGH IMPEDANCE
MSB
MSB