GD25LQ40xIGx 1.8V Uniform Sector Dual and Quad Serial Flash
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7.5. Write Status Register (WRSR) (01H)
The Write Status Register (WRSR) command allows new values to be written to the Status Register. Before it
can be accepted, a Write Enable (WREN) command must previously have been executed. After the Write Enable
(WREN) command has been decoded and executed, the device sets the Write Enable Latch (WEL).
The Write Status Register (WRSR) command has no effect on S15, S10, S1 and S0 of the Status Register. CS#
must be driven high after the eighth or sixteen bit of the data byte has been latched in. If not, the Write Status
Register (WRSR) command is not executed. If CS# is driven high after eighth bit of the data byte, the CMP and
QE and SRP1 bits will be cleared to 0. As soon as CS# is driven high, the self-timed Write Status Register cycle
(whose duration is tW) is initiated. While the Write Status Register cycle is in progress, the Status Register may
still be read to check the value of the Write In Progress (WIP) bit. The Write In Progress (WIP) bit is 1 during
the self-timed Write Status Register cycle, and is 0 when it is completed. When the cycle is completed, the Write
Enable Latch (WEL) is reset.
The Write Status Register (WRSR) command allows the user to change the values of the Block Protect (BP4,
BP3, BP2, BP1 and BP0) bits, to define the size of the area that is to be treated as read-only, as defined in Ta-
ble1. The Write Status Register (WRSR) command also allows the user to set or reset the Status Register Protect
(SRP1 and SRP0) bits in accordance with the Write Protect (WP#) signal. The Status Register Protect (SRP1
and SRP0) bits and Write Protect (WP#) signal allow the device to be put in the Hardware Protected Mode. The
Write Status Register (WRSR) command is not executed once the Hardware Protected Mode is entered.
Figure 6. Write Status Register Sequence Diagram
CS#
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
SCLK
Command
01H
Status Register in
SI
7
6
5
4
3
2
1
0
11 10
9
8
15 14 13 12
MSB
High-Z
SO
Figure 6a. Write Status Register Sequence Diagram (QPI)
CS#
0
1
2
3
4
5
SCLK
Command
01H
4
5
6
7
0
1
2
3
12
8
9
IO0
13
IO1
IO2
IO3
14 10
15 11
Status Register in
Rev.1.0
59 - 19
ELM [ ELM ELECTRONICS ]
