W25X10BV/20BV/40BV
9.2.22 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 W25X10BV/20BV/40BV 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 23.
DO
24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 101 102 103
*
DO
63 62 61 60 59
2
1
0
*=MSB
Figure 23. Read Unique ID Number Instruction Sequence
Publication Release Date: August 20, 2009
Preliminary -- Revision B
- 35 -
WINBOND [ WINBOND ]
