S25FL128SDPMFIG11 Datasheet, PDF (85/153 Pages) SPANSION – MirrorBit Flash Non-Volatile Memory CMOS 3.0 Volt Core with Versatile I/O Serial Peripheral Interface with Multi-I/O

Data Sheet
Figure 10.11 Write Registers (WRR) Command Sequence – 16 data bits
CS#
SCK
SI
SO
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Instruction
High Impedance
Status Register In
Configuration Register In
7654321 07654321 0
MSB
MSB
The Write Registers (WRR) command allows the user to change the values of the Block Protect (BP2, BP1,
and BP0) bits to define the size of the area that is to be treated as read-only. The Write Registers (WRR)
command also allows the user to set the Status Register Write Disable (SRWD) bit to a 1 or a 0. The Status
Register Write Disable (SRWD) bit and Write Protect (WP#) signal allow the BP bits to be hardware
protected.
When the Status Register Write Disable (SRWD) bit of the Status Register is a 0 (its initial delivery state), it is
possible to write to the Status Register provided that the Write Enable Latch (WEL) bit has previously been
set by a Write Enable (WREN) command, regardless of the whether Write Protect (WP#) signal is driven to
the logic high or logic low state.
When the Status Register Write Disable (SRWD) bit of the Status Register is set to a 1, two cases need to be
considered, depending on the state of Write Protect (WP#):
 If Write Protect (WP#) signal is driven to the logic high state, it is possible to write to the Status and
Configuration Registers provided that the Write Enable Latch (WEL) bit has previously been set to a 1 by
initiating a Write Enable (WREN) command.
 If Write Protect (WP#) signal is driven to the logic low state, it is not possible to write to the Status and
Configuration Registers even if the Write Enable Latch (WEL) bit has previously been set to a 1 by a Write
Enable (WREN) command. Attempts to write to the Status and Configuration Registers are rejected, and
are not accepted for execution. As a consequence, all the data bytes in the memory area that are protected
by the Block Protect (BP2, BP1, BP0) bits of the Status Register, are also hardware protected by WP#.
The WP# hardware protection can be provided:
 by setting the Status Register Write Disable (SRWD) bit after driving Write Protect (WP#) signal to the logic
low state;
 or by driving Write Protect (WP#) signal to the logic low state after setting the Status Register Write Disable
(SRWD) bit to a 1.
The only way to release the hardware protection is to pull the Write Protect (WP#) signal to the logic high
state. If WP# is permanently tied high, hardware protection of the BP bits can never be activated.
July 12, 2012 S25FL128S_256S_00_05
S25FL128S and S25FL256S
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