W25Q80BV
- 54 -
7.2.34
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 W25Q80BV 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.
/CS
CLK
DI
(IO
0
)
DO
(IO
1
)
Mode 0
Mode 3
0
1
2
3
4
5
6
7
Instruction (4Bh)
High Impedance
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
/CS
CLK
DI
(IO
0
)
DO
(IO
1
)
24
25
26
27
28
29
30
31
32
33
34
36
37
38
35
23
Mode 0
Mode 3
*
Dummy Byte 1
Dummy Byte 2
39
40
41
42
Dummy Byte 3
Dummy Byte 4
63
62
61
2
1
0
64-bit Unique Serial Number
100
101
102
High Impedance
= MSB
*
Figure 32. Read Unique ID Number Instruction Sequence