ST10F272M-4Q3 STMICROELECTRONICS [STMicroelectronics], ST10F272M-4Q3 Datasheet - Page 35

• Manufacturer Part Number: ST10F272M-4Q3
• Description: 16-bit MCU with 256 Kbyte Flash memory and 20 Kbyte RAM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ST10F272M
5.5
5.5.1
5.5.2
Table 18.
Protection strategy
The protection bits are stored in Non-Volatile Flash cells inside IFlash module, that are read
once at reset and stored in four 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 four 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)
FNVWPIR (0x08 DFB0)
Bit
6
7
8
15
SEQER
RESER
Name
14
WPF
Flash error register (continued)
13
Sequence Error
This bit is automatically set when the control registers (FCR1H/L-FCR0H/L,
FARH/L, FDR1H/L-FDR0H/L) are not correctly filled to execute a valid Write
Operation. In this case no Write Operation is executed. This bit has to be software
reset.
Resume Error
This bit is automatically set when a suspended Program or Erase operation is not
resumed correctly due to a protocol error. In this case the suspended operation is
aborted. This bit has to be software reset.
Write Protection Flag
This bit is automatically set when trying to program or erase in a sector write
protected. In case of multiple Sector Erase, the not protected sectors are erased,
while the protected sectors are not erased and bit WPF is set. This bit has to be
software reset.
Reserved
12
-
11
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