時鐘供給分類
外部時鐘
外部高速時鐘 // HSE
– external 4-to-26 MHz crystal oscillator // 需要外接
外部低速時鐘 // LSE
LSE OSC 32.768K
內部時鐘
內部高速時鐘 // HSI
– Internal 16 MHz factory-trimmed RC (1% accuracy)
The wakeup times given in Table 25 is measured on a wakeup phase with a 16 MHz HSI RC oscillator.
外部高速時鐘
– Internal 32 kHz RC with calibration
– 32 kHz oscillator for RTC with calibration // 供獨立看門狗和自動喚醒單元使用
時鐘倍頻分頻
PLL
啓動時的時鐘配置
On reset the 16 MHz internal RC oscillator is selected as the default CPU clock.
The 16 MHz internal RC oscillator is factory-trimmed to offer 1% accuracy over the full temperature range.
The application can then select as system clock either the RC oscillator or an external 4-26 MHz clock source.
This clock can be monitored for failure. If a failure is detected, the system automatically switches back to the internal RC oscillator and a software interrupt is generated (if enabled). This clock source is input to a PLL thus allowing to increase the frequency up to 168 MHz.
cpu的頻率
frequency up to 168 MHz