Reset and clock control (RCC)
RM0365
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DocID025202 Rev 7
When the programmable factor is ‘1’, the AHB prescaler must be equal to ‘1’.
FCLK acts as Cortex-M4
®
F free-running clock. For more details refer to the
STM32F3xx/F4xx Cortex
®
-M4 programming manual (PM0214)
.
9.2.1 HSE
clock
The high speed external clock signal (HSE) can be generated from two possible clock
sources:
•
HSE external crystal/ceramic resonator
•
HSE user external clock
The resonator and the load capacitors have to be placed as close as possible to the
oscillator pins in order to minimize output distortion and startup stabilization time. The
loading capacitance values must be adjusted according to the selected oscillator.
Figure 15. HSE/ LSE clock sources
Clock source
Hardware configuration
External clock
Crystal/Ceramic
resonators
06Y9
26&B,1
26&B287
*3,2
([WHUQDO
VRXUFH
06Y9
26&B,1
26&B287
&
/
&
/
/RDG
FDSDFLWRUV