FOR MOBILE APPLICATIONS
W25Q256FV
- 77 -
8.2.39
Read JEDEC ID (9Fh)
For compatibility reasons, the W25Q256FV provides several instructions to electronically determine the
identity of the device. The Read JEDEC ID instruction is compatible with the JEDEC standard for SPI
compatible serial memories that was adopted in 2003. The instruction is initiated by driving the /CS pin low
and shifting the instruction code “9Fh”. The JEDEC assigned Manufacturer ID byte for Winbond (EFh) and
two Device ID bytes, Memory Type (ID15-ID8) and Capacity (ID7-ID0) are then shifted out on the falling
edge of CLK with most significant bit (MSB) first as shown in Figure 43a & 43b. For memory type and
capacity values refer to Manufacturer and Device Identification table.
/CS
CLK
DI
(IO
0
)
DO
(IO
1
)
Mode 0
Mode 3
0
1
2
3
4
5
6
7
Instruction (9Fh)
High Impedance
8
9
10
12
13
14
15
Capacity ID7-0
/CS
CLK
DI
(IO
0
)
DO
16
(IO
1
)
17
18
19
20
21
22
23
Manufacturer ID (EFh)
24
25
26
28
29
30
7
6
5
4
3
2
1
0
*
27
15
Mode 0
Mode 3
11
7
6
5
4
3
2
1
0
*
Memory Type ID15-8
= MSB
*
Figure 43a. Read JEDEC ID Instruction (SPI Mode)
/CS
CLK
Mode 0
Mode 3
0
1
IO
0
IO
1
IO
2
IO
3
9Fh
2
3
4
5
12
8
13
9
14
10
15
11
EFh
6
4
0
5
1
6
2
7
3
ID15-8
ID7-0
IOs switch from
Input to Output
Instruction
Mode 0
Mode 3
Figure 43b. Read JEDEC ID Instruction (QPI Mode)
