STM8S003F3 STM8S003K3
Option byte no.
Option bytes
Table 13. Option byte description (continued)
Description
UBC[7:0] User boot code area
0x00: no UBC, no write-protection
0x01: Pages 0 defined as UBC, memory write-protected
0x02: Pages 0 to 1 defined as UBC, memory write-protected
Page 0 and page 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/EEPROM write protection for more details.
OPT1
OPT2
AFR[7:0]
Refer to the following section for alternate function remapping descriptions
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
OPT3
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
0: No reset generated on halt if WWDG active
1: Reset generated on halt if WWDG active
EXTCLK: External clock selection
0: External crystal connected to OSCIN/OSCOUT
1: External clock signal on OSCIN
CKAWUSEL: Auto wakeup unit/clock
0: LSI clock source selected for AWU
1: HSE clock with prescaler selected as clock source for for AWU
OPT4
PRSC[1:0] AWU clock prescaler
0x: 16 MHz to 128 kHz prescaler
10: 8 MHz to 128 kHz prescaler
11: 4 MHz to 128 kHz prescaler
HSECNT[7:0]: HSE crystal oscillator stabilization time
This configures the stabilization time.
0x00: 2048 HSE cycles
OPT5
0xB4: 128 HSE cycles
0xD2: 8 HSE cycles
0xE1: 0.5 HSE cycles
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