64 Mbit SPI Serial Dual I/O Flash
SST25VF064C
Data Sheet
the new commands are properly received by the device.
CE# must be driven low before the RDSR instruction is
entered and remain low until the status data is read. Read-
Status-Register is continuous with ongoing clock cycles
until it is terminated by a low to high transition of the CE#.
See Figure 16 for the RDSR instruction sequence.
Read-Status-Register (RDSR)
The Read-Status-Register (RDSR) instruction allows read-
ing of the status register. The status register may be read at
any time even during a Write (Program/Erase) operation.
When a Write operation is in progress, the Busy bit may be
checked before sending any new commands to assure that
CE#
MODE 3
MODE 0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
SCK
SI
05
HIGH IMPEDANCE
MSB
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
SO
MSB
Status
Register Out
1392 F17.0
FIGURE 16: Read-Status-Register (RDSR) Sequence
Write-Enable (WREN)
The Write-Enable (WREN) instruction sets the Write-
Enable-Latch bit in the Status Register to ‘1’ allowing Write
operations to occur. The WREN instruction must be exe-
cuted prior to any Write (Program/Erase) operation. The
WREN instruction may also be used to allow execution of
the Write-Status-Register (WRSR) instruction; however,
the Write-Enable-Latch bit in the Status Register will be
cleared upon the rising edge CE# of the WRSR instruction.
CE# must be driven high before the WREN instruction is
executed.
CE#
MODE 3
0
1
2
3
4
5
6
7
SCK
MODE 0
06
SI
MSB
HIGH IMPEDANCE
SO
1392 F18.0
FIGURE 17: Write Enable (WREN) Sequence
©2010 Silicon Storage Technology, Inc.
S71392-04-000
04/10
18
SST [ SILICON STORAGE TECHNOLOGY, INC ]
