Proprietary Code Readout Protection (Pcrop) - ST STM32F446 Series Reference Manual

Embedded Flash memory interface
If an erase operation is requested, the WRPERR bit is set when:
•
Mass, bank, sector erase are configured (MER and SER = 1)
•
A sector erase is requested and the Sector Number SNB field is not valid
•
A mass erase is requested while at least one of the user sector is write protected by
option bit (MER = 1 and nWRPi = 0 with 0 ≤ i ≤ 117 bits in the FLASH_OPTCRx register
•
A sector erase is requested on a write protected sector. (SER = 1, SNB = i and
nWRPi = 0 with 0 ≤ i ≤ 117 bits in the FLASH_OPTCRx register)
•
The Flash memory is readout protected and an intrusion is detected.
If a program operation is requested, the WRPERR bit is set when:
•
A write operation is performed on system memory or on the reserved part of the user
specific sector.
•
A write operation is performed to the user configuration sector
• A write operation is performed on a sector write protected by option bit.
•
A write operation is requested on an OTP area which is already locked
•
The Flash memory is read protected and an intrusion is detected.
3.6.5

Proprietary code readout protection (PCROP)

Flash memory user sectors (0 to 7) can be protected against D-bus read accesses by using
the proprietary readout protection (PCROP).
The PCROP protection is selected as follows, through the SPRMOD option bit in the
FLASH_CR register:
•
SPRMOD = 0: nWRPi control the write protection of respective user sectors
•
SPRMOD = 1: nWRPi control the read and write protection (PCROP) of respective
user sectors.
When a sector is readout protected (PCROP mode activated), it can only be accessed for
code fetch through ICODE Bus on Flash interface:
•
Any read access performed through the D-bus triggers a RDERR flag error.
•
Any program/erase operation on a PCROPed sector triggers a WRPERR flag error.
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