RM0440 Rev 4 121/2126
RM0440 Embedded Flash memory (FLASH) for category 3 devices
228
Only when both banks are erased, options are re-programmed with their previous values.
This is also true for FLASH_PCROPxSR and FLASH_PCROPxER registers (x=1,2).
Note: Full mass erase or partial mass erase is performed only when Level 1 is active and Level 0
requested. When the protection level is increased (0->1, 1->2, 0->2) there is no mass erase.
To validate the protection level change, the option bytes must be reloaded through the
OBL_LAUNCH bit in Flash control register.
Figure 4. Changing the read protection (RDP) level
MS33468V2
Options write (RDP level increase) includes:
- Options page erase
- New options program
RDP ≠ 0xAA and RDP ≠ 0xCC
Others options modified
Write options including
RDP = 0xAA
Write options Including
RDP = 0xCC
Write options including
RDP ≠ 0xCC and RDP ≠ 0xAA
Level 1
RDP ≠ 0xAA
RDP ≠ 0xCC
default
Level 2
RDP = 0xCC
Level 0
RDP = 0xAA
RDP = 0xAA
Other(s) option(s) modified
Write options including
RDP = 0xCC
Options write (RDP level decrease) includes
- Full Mass erase or Partial Mass erase to not
erase PCROP pages if PCROP_RDP is cleared
- Backup registers and CCM SRAM erase
- Options page erase
- New options program
Options write (RDP level identical) includes
- Options page erase
- New options program
Table 13. Access status versus protection level and execution modes
Area
Protection
level
User execution (BootFromFlash)
Debug/ BootFromRam/
BootFromLoader
(1)
Read Write Erase Read Write Erase
Flash main
memory
1 Yes Yes Yes No No No
(3)
2 Yes Yes Yes N/A N/A N/A
System
memory
(2)
1 Yes No No Yes No No
2 Yes No No N/A N/A N/A
Option bytes
1 Yes Yes
(3)
Yes Yes Yes
(3)
Yes
2 Yes No No N/A N/A N/A
To Next Page
Loading...
Need help?
General
