W25X10BL Datasheet, PDF (37/53 Pages) Winbond – 1M-BIT, 2M-BIT AND 4M-BIT 2.5V SERIAL FLASH MEMORY WITH 4KB SECTORS AND DUAL I/O SPI

W25X10BL/20BL/40BL
9.2.23 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 W25X10BL/20BL/40BL 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 24.
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
*=MSB
*
63 62 61 60 59 2 1 0
Figure 24. Read Unique ID Number Instruction Sequence
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Publication Release Date: October 14, 2009
Preliminary -- Revision A