AN2430

General description

13/24

1.4.7

Write Unprotection command

Description:

This command allows the user to temporarily disable the write protection for all the Flash

sectors.

When the bootloader receives the write unprotection command, it transmits to the user the

ACK byte.

After the transmission of the ACK byte, the bootloader disables the write protection for all

the Flash sectors.

Finally, at the end of the command, the bootloader transmits the ACK byte if the

unprotection is completed successfully otherwise a NACK byte (0x3F) is returned to the

user and the command is exited.

Figure 7.

Write unprotection command flowchart

Start UN

Received byte

No

== 0x71?

Send ACK byte

Disable the write protection for all

Send ACK byte

End of UN

Unprotection error?

Send NACK byte

the Flash sectors

Yes