AN4286 datasheet(33/38 Pages) STMICROELECTRONICS

33 / 38 page

Bootloader command set

AN4286

33/38

DocID024458 Rev 2

Figure 25. Readout Protect command: slave side

2.12

Readout Unprotect command

The Readout Unprotect command is used to disable the Flash memory read protection.

When the bootloader receives the Readout Unprotect command, it transmits the ACK byte

to the master. After transmission of the ACK byte, the bootloader erases all the Flash

memory sectors and it disables the read protection for the entire Flash memory. If the erase

operation is successful, the bootloader deactivates the RDP.

If the erase operation is unsuccessful, the bootloader transmits a NACK and the read

protection remains active.

The Master has to wait enough time for the read protection disable (which is equivalent to

the Mass Erase time on most products - refer to product datasheet for more information)

before polling for a slave response.

At the end of the Readout Unprotect command, the bootloader transmits an ACK and

generates a system reset to take into account the new configuration of the option byte.

AN4286 데이터시트(PDF) 33 Page - STMicroelectronics