General description

AN2430

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1.4.8

Readout Permanent Protect command

Description:

This command allows the user to permanently enable the readout protection for the entire

Flash.

When the bootloader receives the Readout Permanent Protect command, it transmits to the

user the ACK byte.

After the transmission of the ACK byte, the bootloader permanently enables the readout

protection for the entire Flash.

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

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

and the command is exited.

Note:

When the readout protection is enabled only the following commands are available:

–

The Get Command,

–

The Readout Temporary Unprotect command,

–

The Readout Permanent Unprotect command.

When the readout protection is enabled, in order to boot from the SystemMemory it is

mandatory to reset to ground the pin NJRST.

Figure 8.

Readout permanent protect command flowchart

Start ROP_PRM

Received byte

No

== 0x82?

Send ACK byte

Permanently Enable the Readout

Send ACK byte

End of ROP_PRM

Protection error?

Send NACK byte

protection for the entire Flash

Yes