Datasheet

DescriptionOption byte no.
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
0: No reset generated on halt if WWDG active
1: Reset generated on halt if WWDG active
EXTCLK: External clock selectionOPT4
0: External crystal connected to OSCIN/OSCOUT
1: External clock signal on OSCIN
CKAWUSEL:Auto wake-up unit/clock
0: LSI clock source selected for AWU
1: HSE clock with prescaler selected as clock source for for AWU
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 timeOPT5
0x00: 2048 HSE cycles
0xB4: 128 HSE cycles
0xD2: 8 HSE cycles
0xE1: 0.5 HSE cycles
51/124DocID14771 Rev 12
Option bytesSTM8S105xx