Device Electronic Signature; Unique Device Id Register (96 Bits) - ST STM32F446 Series Reference Manual

RM0390
34

Device electronic signature

The electronic signature is stored in the Flash memory area. It can be read using the
JTAG/SWD or the CPU. It contains factory-programmed identification data that allow the
user firmware or other external devices to automatically match its interface to the
characteristics of the STM32F446xx microcontrollers.
34.1

Unique device ID register (96 bits)

The unique device identifier is ideally suited:
•
for use as serial number (USB string serial number, or other end applications)
• for use as part of the security keys, to increase the security of code in Flash memory
while using and combining this unique ID with software cryptographic primitives and
protocols before programming the memory
•
to activate processes such as secure boot.
The 96-bit unique device identifier provides a reference number, unique for a given device
and in any context. These bits cannot be altered by the user.
The 96-bit unique device identifier can also be read in single bytes/half-words/words in
different ways and then be concatenated using a custom algorithm.
Base address: 0x1FFF 7A10
Address offset: 0x00
Read only = 0xXXXX XXXX, where X is factory-programmed
31 30 29
r r r
15 14 13
r r r
Bits 31:0 U_ID[31:0]: 31:0 unique ID bits
Address offset: 0x04
Read only = 0xXXXX XXXX, where X is factory-programmed
31 30 29 28
r r r r
15 14 13 12
r r r r
Bits 31:0 U_ID[63:32]: 63:32 unique ID bits
28 27 26 25
r r r r
12 11 10 9
r r r r
27 26 25
r r r
11 10 9
r r r
24 23 22
U_ID(31:16)
r r r
8 7 6
U_ID(15:0)
r r r
24 23 22 21
U_ID[63:48]
r r r
8 7 6
U_ID[47:32]
r r r
RM0390 Rev 4
Device electronic signature
21 20 19 18
r r r r
5 4 3 2
r r r r
20 19 18
r r r r
5 4 3 2
r r r r
17 16
r r
1 0
r r
17 16
r r
1 0
r r
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