Embedded Flash memory (FLASH) for category 2 devices RM0440
200/2126 RM0440 Rev 4
5.4 FLASH option bytes
5.4.1 Option bytes description
The option bytes are configured by the end user depending on the application requirements.
As a configuration example, the watchdog may be selected in hardware or software mode
(refer to Section 5.4.2: Option bytes programming).
A double word is split up as follows in the option bytes:
The organization of these bytes inside the information block is as shown in Table 31: Option
byte organization.
The option bytes can be read from the memory locations listed in Table 31: Option byte
organization or from the Option byte registers:
• Flash option register (FLASH_OPTR)
• Flash PCROP1 Start address register (FLASH_PCROP1SR)
• Flash PCROP1 End address register (FLASH_PCROP1ER)
• Flash WRP area A address register (FLASH_WRP1AR)
• Flash WRP area B address register (FLASH_WRP1BR)
User and read protection option bytes
Flash memory address: 0x1FFF 7800
ST production value: 0xFFEF F8AA
Table 30. Option byte format
63-24 23-16 15 -8 7-0 31-24 23-16 15 -8 7-0
Complemented
option byte 3
Complemented
option byte 2
Complemented
option byte 1
Complemented
option byte 0
Option
byte 3
Option
byte 2
Option
byte 1
Option
byte 0
Table 31. Option byte organization
Address [63:56] [55:48] [47:40] [39:32] [31:24] [23:16] [15:8] [7:0]
1FFF7800 USER OPT
RDP USER OPT RDP
1FFF7808 Unused
Unused and
PCROP1_STRT[13:0]
Unused
Unused and
PCROP1_STRT[13:0]
1FFF7810
PCROP_RDP and
Unused
Unused and
PCROP1_END[13:0]
PCROP_RDP and
Unused
Unused and
PCROP1_END[13:0]
1FFF7818 Unused
WRP1A
_END
[5:0]
Unused
WRP1A
_STRT
[5:0]
Unused
WRP1A_
END [5:0]
Unused
WRP1A
_STRT [5:0]
1FFF7820 Unused
WRP2A
_END
[5:0]
Unused
WRP2A
_STRT
[5:0]
Unused
WRP2A_
END [5:0]
Unused
WRP2A
_STRT [5:0]
1FFF7828 Unused
BOOT_
LOCK
Unused
SEC_
SIZE1
Unused
BOOT_
LOCK
Unused
SEC_
SIZE1
To Next Page
General
