STMicroelectronics STM32F05 series Reference Manual page 109

RM0091
Bits 4:3 LSEDRV LSE oscillator drive capability
Set and reset by software to modulate the LSE oscillator's drive capability. A reset of the
backup domain restores the default value.
00: 'Xtal mode' lower driving capability
01: 'Xtal mode' medium low driving capability
10: 'Xtal mode' medium high driving capability
11: 'Xtal mode' higher driving capability (reset value)
Note: The oscillator is in Xtal mode when it is not in bypass mode.
Bit 2 LSEBYP: LSE oscillator bypass
Set and cleared by software to bypass oscillator in debug mode. This bit can be written only
when the external 32 kHz oscillator is disabled.
0: LSE oscillator not bypassed
1: LSE oscillator bypassed
Bit 1 LSERDY: LSE oscillator ready
Set and cleared by hardware to indicate when the external 32 kHz oscillator is stable. After
the LSEON bit is cleared, LSERDY goes low after 6 external low-speed oscillator clock
cycles.
0: LSE oscillator not ready
1: LSE oscillator ready
Bit 0 LSEON: LSE oscillator enable
Set and cleared by software.
0: LSE oscillator OFF
1: LSE oscillator ON
Doc ID 018940 Rev 1
Reset and clock control (RCC)
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