Option bytes
STM8S903K3 STM8S903F3
Option byte no.
Description
Note: Refer to the family reference manual (RM0016) section on
Flash/EEPROM memory readout protection for details.
OPT1
UBC[7:0] User boot code area
0x00: no UBC, no write-protection
0x01: Page 0 defined as UBC, memory write-protected
0x02: Pages 0 to 1 defined as UBC, memory write-protected.
Page 0 and 1 contain the interrupt vectors.
...
0x7F: Pages 0 to 126 defined as UBC, memory write-protected
Other values: Pages 0 to 127 defined as UBC, memory
write-protected
Note: Refer to the family reference manual (RM0016) section on
Flash write protection for more details.
OPT2
OPT3
AFR[7:0]
Refer to following section for alternate function remapping decriptions
of bits [7:2] and [1:0] respectively.
HSITRIM:High speed internal clock trimming register size
0: 3-bit trimming supported in CLK_HSITRIMR register
1: 4-bit trimming supported in CLK_HSITRIMR register
LSI_EN:Low speed internal clock enable
0: LSI clock is not available as CPU clock source
1: LSI clock is available as CPU clock source
IWDG_HW: Independent watchdog
0: IWDG Independent watchdog activated by software
1: IWDG Independent watchdog activated by hardware
WWDG_HW: Window watchdog activation
0: WWDG window watchdog activated by software
1: WWDG window watchdog activated by hardware
WWDG_HALT: Window watchdog reset on halt
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STMICROELECTRONICS [ ST ]
