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M25PE80
Write to Lock Register (WRLR)
The Write to Lock Register (WRLR) instruction al-
lows bits to be changed in the Lock Registers. Be-
fore it can be accepted, a Write Enable (WREN)
instruction must previously have been executed.
After the Write Enable (WREN) instruction has
been decoded, the device sets the Write Enable
Latch (WEL).
The Write to Lock Register (WRLR) instruction is
entered by driving Chip Select (S) Low, followed
by the instruction code, three address Bytes
(pointing to any address in the targeted sector/
sub-sector) and one data Byte on Serial Data Input
(D).
The instruction sequence is shown in
Figure 17.
Chip Select (S) must be driven High after the
eighth bit of the data Byte has been latched in, oth-
erwise the Write to Lock Register (WRLR) instruc-
tion is not executed.
When the Write to Lock Register (WRLR) instruc-
tion has been successfully executed, the Write En-
able Latch (WEL) bit is reset after a delay time less
than t
SHSL
minimum value.
Any Write to Lock Register (WRLR) instruction,
while an Erase, Program or Write cycle is in
progress, is rejected without having any effects on
the cycle that is in progress.
Figure 17. Write to Lock Register (WRLR) Instruction Sequence
Table 9. Lock Register In
Note: 1. b6-b4 and b1-b0 must be reset to ‘0’.
2. b6-b2 must be reset to ‘0’.
Sector
Bit
Value
All Sectors Except for Sector 0
and Sector 15
b7-b2
‘0’
b1
Sector Lock Down Bit Value (refer to
Table 8.
)
b0
Sector Write Lock Bit Value (refer to
Table 8.
)
Sector 0
Sector 15
b7
‘1’
Only b3 and b2 are taken into account to modify the sub-
sector Write Lock and Lock Down bits
(1)
‘0’
Only b1 and b0 are taken into account to modify the sector
Write Lock and Lock Down bits
(2)
b3
Sub-sector Lock Down Bit value (refer to
Table 8.
)
b2
Sub-sector Write Lock Bit Value (refer to
Table 8.
)
b1
Sector Lock Down Bit Value (refer to
Table 8.
)
b0
Sector Write Lock Bit Value (refer to
Table 8.
)
AI10784
C
D
S
23
2
1
3
4
5
6
7
8
9 10
28 29 30 31 32 33 34 35
22 21
3
2
1
0
36 37 38
Instruction
24-Bit Address
0
7
6
5
4
3
2
0
1
Lock Register
In
39
MSB
MSB