ST10F272M-4Q3 STMICROELECTRONICS [STMicroelectronics], ST10F272M-4Q3 Datasheet - Page 37

• 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
5.5.6
5.5.7
Flash non-volatile access protection register 1 high (FNVAPR1H)
FNVAPR1H (0x08 DFBE)
PEN15PEN14PEN13PEN12PEN11PEN10 PEN9 PEN8 PEN7 PEN6 PEN5 PEN4 PEN3 PEN2 PEN1 PEN0
Table 22.
XBus Flash volatile temporary access unprotection register
(XFVTAUR0)
XFVTAUR0 (0x00 EB50)
Table 23.
Access protection
The IFlash module has one level of access protection (access to data both in Reading and
Writing).
When bit ACCP of FNVAPR0 is programmed at 0 and bit TAUB in XFVTAUR0 is set at 0, the
IFlash module becomes access protected (data in the IFlash module can be read only if the
current execution is from the IFlash module itself).
Trying to read into the access protected Flash from internal RAM or external memories will
output a dummy data (software trap 009Bh).
When the Flash module is protected in access, data access through PEC transfers is also
forbidden. To read/write data through PEC in a protected Bank, first it is necessary to
temporarily unprotect the Flash module.
15:0 PEN[15:0]
RW
Bit
Bit
15
15
0
RW
14
14
Name
Name
TAUB
RW
Flash non-volatile access protection register 1 high
XBus Flash volatile temporary access unprotection register
13
13
Temporary Access Unprotection bit
If this bit is set to 1, the Access Protection is temporary disabled.
The fact that this bit can be written only while executing from IFlash guarantees that
only a code executed in IFlash can unprotect the IFlash when it is Access
Protected.
Protections Enable 15-0
If bit PENx is programmed at 0 and bit PDSx+1 is erased at 1, the action of bit
ACCP is enabled again. Bit PENx can be programmed at 0 only if bit PDSx has
already been programmed at 0.
RW
12
12
RW
11
11
RW
10
10
RW
9
9
Reserved
NVR
NVR
RW
8
8
-
RW
7
7
Function
Function
RW
6
6
RW
5
5
RW
4
4
Internal Flash memory
RW
3
3
Delivery value: FFFFh
Reset value: 0000h
RW
2
2
RW
1
1
37/176
TAUB
RW
RW
0
0