ST STM32L4+ Series Reference Manual page 245

RM0432
LSI RC 32 kHz
LSCO
OSC32_OUT
LSE OSC
32.768 kHz
OSC32_IN
MCO
/ 1→16
OSC_OUT
HSE OSC
4-48 MHz
OSC_IN
Clock
detector
HSI RC
16 MHz
MSI RC
100 kHz – 48 MHz
RC 48 MHz
PLL
PLLSAI3CLK
/ P
PLL48M1CLK
/ Q
PLLCLK
/ R
PLLSAI1
PLLSAI1CLK
/ P
PLL48M2CLK
/ Q
PLLADC1CLK
/ R
PLLSAI2
PLLSAI2CLK
/ P
/ Q
PLLLCDCLK
/ R
SAI1_EXTCLK
SAI2_EXTCLK
Figure 18. Clock tree for STM32L4P5xx and STM32L4Q5xx devices
LSE
LSI
MSI
HSI16
HSE
SYSCLK
PLLCLK
HSI48
HSE
MSI
HSI16
/ M
HSE
HSI16
/ M
HSI16
/ M
HSI16
/32
AHB PRESC
Clock
source
control
MSI
SYSCLK
HSI16
MSI
MSI
PLLSAI2DIVR
RM0432 Rev 6
Reset and clock control (RCC)
to AHB bus, core, memory and DMA
HCLK FCLK Cortex free running clock
/ 1,2,..512
/ 8
PCLK1
APB1 PRESC
/ 1,2,4,8,16
LSE
HSI16
SYSCLK
HSI16
SYSCLK
LSI
LSE
HSI16
PCLK2
APB2 PRESC
/ 1,2,4,8,16
LSE
HSI16
SYSCLK
48 MHz clock to USB, RNG
SYSCLK
MSI
HSI16
to IWDG
to RTC
to PWR
to Cortex system timer
to APB1 peripherals
x1 or x2
to TIMx
x=2..7
to USARTx
X=2..5
to LPUART1
to I2Cx
x=1,2,3,4
to LPTIMx
x=1,2
to OCTOSPIx
x=1,2
CRS clock
to APB2 peripherals
x1 or x2
to TIMx
x=1,8,15,16,17
to
USART1
to SDMMCx
x=1,2
to ADCx
X=1,2
DFSDM
audio clock
to SAI1
LTDC clock
to SAI2
MSv61129V2
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