Reset and Clock Control (RCC) stm32l

Reset:

1. System Reset: A Systems Reset Sets all registers-their reset values except for the RTC, RTC Backup
Registers and Control/status Register, RCC_CSR

Reset Source view: RCC_CSR

Option byte loader:stm32l15xxx Flash Programming Manual (PM0062)

2. Power RESET:A Power Reset sets all registers to their reset values including for the RTC domain

3. RTC and Backup registers Reset:

Reset Source: A software reset, triggered by setting the Rtcrst bit in the RCC_CSR register

Power Reset (BOR/POR/PDR)

Clocks:

Features of each clock:

1, HSE: High precision

2. HSI: Low cost, faster start-up time than HSE

3, MSI: Reset, Wake up. MSI is the system clock.

Reduced power consumption and wake-up time

4, Pll:provide A-MHz clock to the USB or SDIO. Multiply frequency for each range of VCore

5, LSE: Low power consumption, high precision. For rtc/calendars, timings, etc.

6, LSI: low power consumption. Clock is provided for IWDG in Stop standby mode

System Clock Source: Hsi,hse,pll,msi

Clock safety system: take corresponding measures when external clocks fail to protect application execution

RTC vs. LCD Clock Source: LSE or LSI

Watchdog Clock:lsi

MCO: Clock output pin (PA8)

Clock measured by: TIM9/TIM10/TIM11

Reset and Clock Control (RCC) stm32l