Osc Clock; Osc Clock Supply - ST STM32 User Manual

UM1974
6.8

OSC clock

6.8.1

OSC clock supply

There are four ways to configure the pins corresponding to the external high-speed clock
(HSE):
•
MCO from ST-LINK (Default): MCO output of ST-LINK is used as input clock. This
frequency cannot be changed, it is fixed at 8 MHz and connected to the
PF0/PH0-OSC_IN of STM32 microcontroller. The configuration must be:
–
–
–
•
HSE on-board oscillator from X3 crystal (not provided): for typical frequencies and
its capacitors and resistors, refer to the STM32 microcontroller datasheet and to the
Oscillator design guide for STM8S, STM8A and STM32 microcontrollers Application
note (AN2867) for the oscillator design guide. The X3 crystal has the following
characteristics: 8 MHz, 8 pF, 20 ppm. It is recommended to use NX3225GD-8.000M-
EXS00A-CG04874 manufactured by NIHON DEMPA KOGYO CO., LTD. The
configuration must be:
–
–
–
–
•
Oscillator from external PF0/PH0: from an external oscillator through the pin 29 of
the CN11 connector. The configuration must be:
–
–
–
•
HSE not used: PF0/PH1 and PF1/PH1 are used as GPIOs instead of as clock. The
configuration must be:
–
–
–
SB148 OFF
SB112 and SB149 ON
SB8 and SB9 OFF
SB148 and SB163 OFF
SB8 and SB9 ON
C37 and C38 soldered with 4.3 pF capacitors
SB112 and SB149 OFF
SB148 ON
SB112 and SB149 OFF
SB8 and SB9 removed
SB148 and SB163 ON
SB112 and SB149 (MCO) OFF
SB8 and SB9 removed
UM1974 Rev 9
Hardware layout and configuration
25/85
84