FOR MOBILE APPLICATIONS
W25Q256FV
Publication Release Date: May 13, 2012
- 78 - Preliminary - Revision M1
8.2.40
Read SFDP Register (5Ah)
The W25Q256FV features a 256-Byte Serial Flash Discoverable Parameter (SFDP) register that contains
information about device configurations, available instructions and other features. The SFDP parameters
are stored in one or more Parameter Identification (PID) tables. Currently only one PID table is specified,
but more may be added in the future. The Read SFDP Register instruction is compatible with the SFDP
standard initially established in 2010 for PC and other applications, as well as the JEDEC standard
JESD216 that is published in 2011. Most Winbond SpiFlash Memories shipped after June 2011 (date
code 1124 and beyond) support the SFDP feature as specified in the applicable datasheet.
The Read SFDP instruction is initiated by driving the /CS pin low and shifting the instruction code “5Ah”
followed by a 24-bit address (A23-A0)
(1)
into the DI pin. Eight “dummy” clocks are also required before the
SFDP register contents are shifted out on the falling edge of the 40
th
CLK with most significant bit (MSB)
first as shown in Figure 44. For SFDP register values and descriptions, please refer to the Winbond
Application Note for SFDP Definition Table.
Note: 1. A23-A8 = 0; A7-A0 are used to define the starting byte address for the 256-Byte SFDP Register.
/CS
CLK
DI
(IO
0
)
DO
(IO
1
)
Mode 0
Mode 3
0
1
2
3
4
5
6
7
Instruction (5Ah)
High Impedance
8
9
10
28
29
30
31
24-Bit Address
23
22
21
3
2
1
0
Data Out 1
*
/CS
CLK
DI
(IO
0
)
DO
32
(IO
1
)
33
34
35
36
37
38
39
Dummy Byte
High Impedance
40
41
42
44
45
46
47
48
49
50
51
52
53
54
55
7
6
5
4
3
2
1
0
7
Data Out 2
7
6
5
4
3
2
1
0
43
31
0
*
7
6
5
4
3
2
1
0
= MSB
*
*
Figure 44. Read SFDP Register Instruction Sequence Diagram (SPI Mode only)
Only 24-Bit Address is required when the device is operating in either 3-Byte or 4-Byte Address Mode
