IS25LQ080 Datasheet, PDF (51/54 Pages) Integrated Silicon Solution, Inc – 8 Mbit Single Operating Voltage Serial Flash Memory With 104

IS25LQ080
Appendix2: Sector Unlock function
Instruction Name
SECT_UNLOCK
SECT_LOCK
Hex
Code
26h
24h
Operation
Sector unlock
Sector lock
SEC_UNLOCK COMMAND OPERATION
The Sector unlock command allows the user to
select a specific sector to allow program and erase
operations. This instruction is effective when the
blocks are designated as write-protected through
the BP0, BP1, BP2 and BP3 bits in the status
register. Only one sector can be enabled at any
time. To enable a different sector, a previously
Figure d. Sector Unlock Sequence
Sector unlock
Command
Cycle
4 Bytes
1 Byte
Maximum
Frequency
100 MHz
100 MHz
enabled sector must be disabled by executing a
Sector Lock command. The instruction code is
followed by a 24-bit address specifying the target
sector, but A0 through A11 are not decoded. The
remaining sectors within the same block remain in
read-only mode.
CS
SCK
12
78
12
7 8 9 10
15 16 17 18
23 24 25 26
31 32
SI
06h
26h
A23-A16 A15-A8 A7-A0
In the sector unlock procedure, [A11:A0] needs equal to “0”, unlock procedure is
completed, otherwise chip will regard it as illegal command.
Note: 1.If the clock number will not match 8 clocks(command)+ 24 clocks (address), it will be ignored.
2.It must be executed write enable (06h) before sector unlock instructions.
Integrated Silicon Solution, Inc.- www.issi.com
Rev. A
10/18/2012
51