2 Mbit / 4 Mbit SPI Serial Flash
SST25LF020A / SST25LF040A
Data Sheet
Sector-Erase
The Sector-Erase instruction clears all bits in the selected 4
KByte sector to FFH. A Sector-Erase instruction applied to
a protected memory area will be ignored. Prior to any Write
operation, the Write-Enable (WREN) instruction must be
executed. CE# must remain active low for the duration of
the any command sequence. The Sector-Erase instruction
is initiated by executing an 8-bit command, 20H, followed
by address bits [A23-A0]. Address bits [AMS-A12]
(AMS = Most Significant address) are used to determine the
sector address (SAX), remaining address bits can be VIL or
VIH. CE# must be driven high before the instruction is exe-
cuted. The user may poll the Busy bit in the software status
register or wait TSE for the completion of the internal self-
timed Sector-Erase cycle. See Figure 8 for the Sector-
Erase sequence.
CE#
MODE 3
0
1
2
3
4
5
6
7
8
15 16
23
31
24
MODE 0
SCK
20
ADD.
MSB
ADD.
ADD.
SI
MSB
HIGH IMPEDANCE
SO
1242 F08.0
FIGURE 8: SECTOR-ERASE SEQUENCE
Block-Erase
The Block-Erase instruction clears all bits in the selected 32
KByte block to FFH. A Block-Erase instruction applied to a
protected memory area will be ignored. Prior to any Write
operation, the Write-Enable (WREN) instruction must be
executed. CE# must remain active low for the duration of
any command sequence. The Block-Erase instruction is
initiated by executing an 8-bit command, 52H, followed by
address bits [A23-A0]. Address bits [AMS-A15] (AMS = Most
significant address) are used to determine block address
(BAX), remaining address bits can be VIL or VIH. CE# must
be driven high before the instruction is executed. The user
may poll the Busy bit in the software status register or wait
TBE for the completion of the internal self-timed Block-
Erase cycle. See Figure 9 for the Block-Erase sequence.
CE#
MODE 3
0
1
2
3
4
5
6
7
8
15 16
23
31
24
MODE 0
SCK
52
ADD.
MSB
ADD.
ADD.
SI
MSB
HIGH IMPEDANCE
SO
1242 F09.0
FIGURE 9: BLOCK-ERASE SEQUENCE
©2006 Silicon Storage Technology, Inc.
S71242-05-000
1/06
13
SST [ SILICON STORAGE TECHNOLOGY, INC ]
