STM32 SDK Terms

RCC

• HSI internal high speed crystal
• HSE external high speed crystal

• LSE external low speed crystal, 32.768Khz

• HSE = High-speed external clock signal
• HSI = High-speed internal clock signal
• LSI = Low-speed internal clock signal
• LSE = Low-speed external clock signal
• MSI = Multispeed internal clock signal

• clock source (SYSCLKS)
• PCLK1 low speed / The APB1 clock (PCLK1) = APB low-speed clock (PCLK1)

• PCLK2 high speed / The APB2 clock (PCLK2) = APB highspeed clock (PCLK2)

• AHB clock (HCLK)

reference

• RM0377 Reference manual - https://www.st.com/resource/en/reference_manual/dm00108282-ultralowpower-stm32l0x1-advanced-armbased-32bit-mcus-stmicroelectronics.pdf
• clock tree