ST10F276-4TR3 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST10F276-4TR3

16-bit MCU with MAC unit 832 Kbyte Flash memory and 68 Kbyte RAM

STMicroelectronics 

Internal Flash memory

ST10F276E

4.4.8

Flash non-volatile access protection register 1 high

FNVAPR1H (0x0E DFBE)

NVR

Delivery value: FFFFh

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

PEN15 PEN14 PEN13 PEN12 PEN11 PEN10 PEN9 PEN8 PEN7 PEN6 PEN5 PEN4 PEN3 PEN2 PEN1 PEN0

RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW

Table 25. Flash non-volatile access protection register 1 high

Bit

Function

PEN15-0

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.

4.4.9

Access protection

The Flash modules have one level of access protection (access to data both in Reading and

Writing): if bit ACCP of FNVAPR0 is programmed at 0, the IFlash module become access

protected: data in the IFlash module can be read/written only if the current execution is from

the IFlash module itself.

Protection can be permanently disabled by programming bit PDS0 of FNVAPR1H, in order

to analyze rejects. Allowing PDS0 bit programming only when ACCP bit is programmed,

guarantees that only an execution from the Flash itself can disable the protections.

Protection can be permanently enabled again by programming bit PEN0 of FNVAPR1L. The

action to disable and enable again Access Protections in a permanent way can be executed

a maximum of 16 times.

Trying to write into the access protected Flash from internal RAM will be unsuccessful.

Trying to read into the access protected Flash from internal RAM will output a dummy data.

When the Flash module is protected in access, also the data access through PEC of a

peripheral is forbidden. To read/write data in PEC mode from/to a protected bank, first it is

necessary to temporary unprotect the Flash module.

Due to ST10 architecture, the XFLASH is seen as external memory: this makes impossible

to access protect it from real external memory or internal RAM. Table 26 summarizes all

levels of possible Access protection: in particular, supposing to enable all possible access

protections, when fetching from a memory as listed in the first column, what is possible and

what is not possible to do (see column headers) is shown in the table.

Table 26. Summary of access protection level

Memory fetch source

Read IFLASH/ Read XFLASH/

Jump to

Jump to

IFLASH

XFLASH

Read FLASH

Registers

Fetching from IFLASH

Yes / Yes

Yes / Yes

Yes

Fetching from XFLASH

No / Yes

Yes / Yes

Yes

Fetching from IRAM

No / Yes

Yes / Yes

Yes

Write FLASH

Registers

Yes

No

No

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Doc ID 12303 Rev 3

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