
2 Mbit SPI Serial Flash
A Microchip Technology Company
SST25VF020B
Data Sheet
CE#
SCK
MODE 3
MODE 0
0 1 2 3 4 5 6 7
MODE 3
MODE 0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
STATUS
STATUS
REGISTER
REGISTER 1
SI
50 or 06
01
7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
SO
MSB
MSB
HIGH IMPEDANCE
MSB
MSB
1417 EWSR1.0
Figure 21: Enable-Write-Status-Register (EWSR) or Write-Enable (WREN) and
Write-Status-Register (WRSR) Word-Data Input Sequence
The WRSR instruction can either execute a byte-data or a word-data input. Extra data/clock input, or
within byte-/word-data input, will not be executed. The reason for the byte support is for backward com-
patibility to products where WRSR instruction sequence is followed by only a byte-data.
JEDEC Read-ID
The JEDEC Read-ID instruction identifies the device as SST25VF020B and the manufacturer as SST.
The device information can be read from executing the 8-bit command, 9FH. Following the JEDEC
Read-ID instruction, the 8-bit manufacturer’s ID, BFH, is output from the device. After that, a 16-bit
device ID is shifted out on the SO pin. Byte 1, BFH, identifies the manufacturer as SST. Byte 2, 25H,
identifies the memory type as SPI Serial Flash. Byte 3, 8CH, identifies the device as SST25VF020B.
The instruction sequence is shown in Figure 22. The JEDEC Read ID instruction is terminated by a low
to high transition on CE# at any time during data output.
CE#
MODE 3
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
SCK
SI
MODE 0
9F
SO
HIGH IMPEDANCE
BF
25
8C
MSB
MSB
1417 JEDECID.1
Figure 22: JEDEC Read-ID Sequence
Table 7: JEDEC Read-ID Data
Device ID
Manufacturer’s ID
Byte1
BFH
Memory Type
Byte 2
25H
Memory Capacity
Byte 3
8CH
T7.0 25054
?2012 Silicon Storage Technology, Inc.
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