S25FL128S, S25FL256S
Figure 9.9 BRAC (B9h) Command Sequence
CS#
SCK
SI
SO
0 12 3 4 5 6 7
Instruction
76543210
MSB
High Impedance
9.3.7
Write Registers (WRR 01h)
The Write Registers (WRR) command allows new values to be written to both the Status Register-1 and Configuration Register.
Before the Write Registers (WRR) command can be accepted by the device, a Write Enable (WREN) command must be received.
After the Write Enable (WREN) command has been decoded successfully, the device will set the Write Enable Latch (WEL) in the
Status Register to enable any write operations.
The Write Registers (WRR) command is entered by shifting the instruction and the data bytes on SI. The Status Register is one data
byte in length.
The Write Registers (WRR) command will set the P_ERR or E_ERR bits if there is a failure in the WRR operation. Any Status or
Configuration Register bit reserved for the future must be written as a 0.
CS# must be driven to the logic high state after the eighth or sixteenth bit of data has been latched. If not, the Write Registers (WRR)
command is not executed. If CS# is driven high after the eighth cycle then only the Status Register-1 is written; otherwise, after the
sixteenth cycle both the Status and Configuration Registers are written. When the configuration register QUAD bit CR[1] is 1, only
the WRR command format with 16 data bits may be used.
As soon as CS# is driven to the logic high state, the self-timed Write Registers (WRR) operation is initiated. While the Write
Registers (WRR) operation 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 a 1 during the self-timed Write Registers (WRR) operation, and is a 0 when it is completed. When
the Write Registers (WRR) operation is completed, the Write Enable Latch (WEL) is set to a 0. The maximum clock frequency for the
WRR command is 133 MHz.
Figure 9.10 Write Registers (WRR) Command Sequence – 8 data bits
CS#
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
SCK
Instruction
Status Register In
SI
7654321 0
MSB
High Impedance
SO
Document Number: 001-98283 Rev. *I
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