ST10F272B_12 STMICROELECTRONICS [STMicroelectronics], ST10F272B_12 Datasheet - Page 39

• Manufacturer Part Number: ST10F272B_12
• Description: 16-bit MCU with 256 Kbyte Flash memory and 12/20 Kbyte RAM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ST10F272B/ST10F272E
5.5
5.5.1
5.5.2
Protection strategy
The protection bits are stored in Non Volatile Flash cells inside IFLASH module, that are
read once at reset and stored in 4 Volatile registers. Before they are read from the Non
Volatile cells, all the available protections are forced active during reset.
The protections can be programmed using the Set Protection operation (see Flash Control
Registers paragraph), that can be executed from all the internal or external memories
except from the Flash itself.
Two kind of protections are available: write protections to avoid unwanted writings and
access protections to avoid piracy. In next paragraphs all different level of protections are
shown, and architecture limitations are highlighted as well.
Protection registers
The 4 Non Volatile Protection Registers are one time programmable for the user.
One register (FNVWPIR) is used to store the Write Protection fuses respectively for each
sector IFLASH module. The other three Registers (FNVAPR0 and FNVAPR1L/H) are used
to store the Access Protection fuses.
Flash non volatile write protection I register
FNVWPIR (0x08 DFB0)
Table 19.
W0P(9:0)
15
Bit
14
Flash non volatile write protection I register
13
Write Protection Bank 0 / Sectors 9-0 (IFLASH)
These bits, if programmed at 0, disable any write access to the sectors of Bank 0
(IFLASH)
12
reserved
11
Doc ID 11917 Rev 3
10
9
NVR
8
W0P7W0P6W0P5W0P4W0P3W0P2W0P1W0P0
RW
7
Function
RW
6
RW
5
RW
4
Internal Flash memory
RW
3
Reset value: FFFFh
RW
2
RW
1
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RW
0