w25q64dw Winbond Electronics Corp America, w25q64dw Datasheet - Page 58

• Manufacturer Part Number: w25q64dw
• Description: 1.8v 64m-bit Serial Flash Memory With Dual/quad Spi & Qpi
• Manufacturer: Winbond Electronics Corp America

10.2.33 Read Unique ID Number (4Bh)
The Read Unique ID Number instruction accesses a factory-set read-only 64-bit number that is unique to
each W25Q64DW device. The ID number can be used in conjunction with user software methods to help
prevent copying or cloning of a system. The Read Unique ID instruction is initiated by driving the /CS pin
low and shifting the instruction code “4Bh” followed by a four bytes of dummy clocks. After which, the 64-
bit ID is shifted out on the falling edge of CLK as shown in Figure 32.
(IO
(IO
(IO
(IO
CLK
CLK
/CS
/CS
DO
DO
DI
DI
0
1
0
1
)
)
)
)
Mode 3
Mode 0
23
*
24
= MSB
25
0
26
Dummy Byte 3
1
27
Instruction (4Bh)
2
28
Figure 32. Read Unique ID Number Instruction (SPI Mode only)
3
High Impedance
29
4
30
5
31
6
32
7
33
8
Dummy Byte 4
34
9
High Impedance
- 58 -
35
10
Dummy Byte 1
36
11
37
12
38
13
39
14
63
*
40
15
64-bit Unique Serial Number
62
41
16
61
42
17
18
Dummy Byte 2
W25Q64DW
19
2
20
1
21
0
22
Mode 3
Mode 0
23