Datasheet
Factory
default
setting
Option bitsOption
byte no.
Option
name
Addr.
01234567
FFhReserved
NOPT6
0x480C
00hReserved
OPT7
Reserved0x480D
FFhReserved
NOPT7
0x480E
00hBL[7:0]
OPTBL
Bootloader0x487E
FFhNBL[7:0]
NOPTBL
0x487F
Table 13: Option byte description
DescriptionOption byte no.
ROP[7:0] Memory readout protection (ROP)OPT0
AAh: Enable readout protection (write access via SWIM protocol)
Note: Refer to the family reference manual (RM0016) section on
Flash/EEPROM memory readout protection for details.
UBC[7:0] User boot code areaOPT1
0x00: no UBC, no write-protection
0x01: Page 0 to 1 defined as UBC, memory write-protected
0x02: Page 0 to 3 defined as UBC, memory write-protected
0x03: Page 0 to 4 defined as UBC, memory write-protected
...
0x3E: Pages 0 to 63 defined as UBC, memory write-protected
Other values: Reserved
Note: Refer to the family reference manual (RM0016) section on
Flash write protection for more details.
AFR[7:0]OPT2
Refer to following table for the alternate function remapping
decriptions of bits [7:2].
HSITRIM:High speed internal clock trimming register sizeOPT3
0: 3-bit trimming supported in CLK_HSITRIMR register
1: 4-bit trimming supported in CLK_HSITRIMR register
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STM8S105xxOption bytes