Write Protections - ST STM32F413 Reference Manual

Embedded Flash memory interface
--
Memory area
Main Flash Memory
Option Bytes
OTP
1. The main Flash memory is only erased when the RDP changes from level 1 to 0. The OTP area remains unchanged.
Figure 5
3.6.4

Write protections

Up to 12 user sectors in Flash memory can be protected against unwanted write operations
due to loss of program counter contexts. When the non-write protection nWRPi bit
(0 ≤ i ≤ 11) in the FLASH_OPTCR registers is low, the corresponding sector cannot be
erased or programmed. Consequently, a mass erase cannot be performed if one of the
sectors is write-protected.
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Table 11. Access versus read protection level
Debug features, Boot from RAM or
Protection
from System memory bootloader
Level
Read
Level 1
Level 2
Level 1
Level 2
Level 1
Level 2
shows how to go from one RDP level to another.
DocID029473 Rev 3
Write Erase
(1)
NO NO
NO
YES
NO
NO NA
NO NA
Figure 5. RDP levels
Booting from Flash memory
Read Write
YES
YES
YES
NO
YES
YES
RM0430
Erase
NA
NA