2 Mbit / 4 Mbit SPI Serial Flash
SST25LF020A / SST25LF040A
Data Sheet
Block Protection (BP1, BP0)
Block Protection Lock-Down (BPL)
The Block-Protection (BP1, BP0) bits define the size of the
memory area, as defined in Table 5, to be software pro-
tected against any memory Write (Program or Erase)
operations. The Write-Status-Register (WRSR) instruction
is used to program the BP1 and BP0 bits as long as WP#
is high or the Block-Protect-Lock (BPL) bit is 0. Chip-Erase
can only be executed if Block-Protection bits are both 0.
After power-up, BP1 and BP0 are set to 1.
WP# pin driven low (VIL), enables the Block-Protection-
Lock-Down (BPL) bit. When BPL is set to 1, it prevents any
further alteration of the BPL, BP1, and BP0 bits. When the
WP# pin is driven high (VIH), the BPL bit has no effect and
its value is “Don’t Care”. After power-up, the BPL bit is
reset to 0.
1
TABLE 5: SOFTWARE STATUS REGISTER BLOCK PROTECTION
Status
Register
Bit
Protected Memory Area
Protection Level
0
BP1
BP0
2 Mbit
4 Mbit
0
0
1
1
0
1
0
1
None
None
1 (1/4 Memory Array)
2 (1/2 Memory Array)
3 (Full Memory Array)
030000H-03FFFFH
020000H-03FFFFH
000000H-03FFFFH
060000H-07FFFFH
040000H-07FFFFH
000000H-07FFFFH
T5.0 1242
1. Default at power-up for BP1 and BP0 is ‘11’.
Auto Address Increment (AAI)
The Auto Address Increment Programming-Status bit pro-
vides status on whether the device is in AAI programming
mode or Byte-Program mode. The default at power up is
Byte-Program mode.
©2006 Silicon Storage Technology, Inc.
S71242-05-000
1/06
7
SST [ SILICON STORAGE TECHNOLOGY, INC ]
