ST10F276 datasheet(41/229 Pages) STMICROELECTRONICS

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ST10F276

Internal Flash memory

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4.5.10

Write protection

The Flash modules have one level of Write Protections: each Sector of each Bank of each

Flash Module can be Software Write Protected by programming at 0 the related bit WyPx of

FNVWPXRH/L-FNVWPIRH/L registers.

4.5.11

Temporary unprotection

Bits WyPx of FNVWPXRH/L-FNVWPIRH/L can be temporary unprotected by executing the

Set Protection operation and writing 1 into these bits.

Bit ACCP can be temporary unprotected by executing the Set Protection operation and

writing 1 into these bits, but only if these write instructions are executed from the Flash

Modules.

To restore the write and access protection bits it is necessary to reset the microcontroller or

to execute a Set Protection operation and write 0 into the desired bits.

It is not necessary to temporary unprotect an access protected Flash in order to update the

code: it is, in fact, sufficient to execute the updating instructions from another Flash Bank.

In reality, when a temporary unprotection operation is executed, the corresponding volatile

protection set operation), will continue to maintain the 0. For this reason, the User software

must be in charge to track the current protection status (for instance using a specific RAM

area), it is not possible to deduce it by reading the non volatile register content (a temporary

unprotection cannot be detected).

Fetching from XRAM

No / Yes

Yes / Yes

Yes

Fetching from External

Memory

No / Yes

Yes / Yes

Yes

Table 26.

Summary of access protection level

Read IFLASH /

Jump to

IFLASH

Read XFLASH

/Jump to

XFLASH

Read FLASH

Registers

Write FLASH

Registers

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