STMicroelectronics Nucleo Development Board for STM32 Microcontrollers NUCLEO-F103RB NUCLEO-F103RB Data Sheet

22/54

DocID025833 Rev 5

There are four ways to configure the pins corresponding to external high-speed clock 
external high-speed clock (HSE):
•

MCO from ST-LINK: MCO output of ST-LINK MCU is used as input clock. This 
frequency cannot be changed, it is fixed at 8 MHz and connected to PF0/PD0/PH0-
OSC_IN of STM32 microcontroller. 
The following configuration is needed:
–

SB54, SB55 OFF

–

R35,R37

 

removed

–

SB16, SB50

 

ON

•

HSE oscillator on-board from X3 crystal (not provided): for typical frequencies and 
its capacitors and resistors, please refer to STM32 microcontroller datasheet. Please 
refer to the AN2867 for oscillator design guide for STM32 microcontrollers..
The following configuration is needed:
–

SB54, SB55 OFF

–

R35, R37 soldered

–

C33, C34 soldered

–

SB16, SB50

 

OFF

•

Oscillator from external PF0/PD0/PH0: from an external oscillator through pin 29 of 
the CN7 connector. 
The following configuration is needed:
–

SB55  ON

–

SB50

 

OFF

–

R35,R37 removed

•

HSE not used: PF0/PD0/PH1 and PF1/PD1/PH1 are used as GPIO instead of Clock
The following configuration is needed:
–

SB54 & SB55 ON

–

R35 and R37 removed

–

SB50 (MCO) OFF

There are two possible default configurations of the HSE pins depending on the version of 
NUCLEO board hardware.

The board version MB1136 C-01 or MB1136 C-02 is mentioned on sticker  placed on bottom 
side of the PCB.

The board marking MB1136 C-01 corresponds to a board, configured for HSE not used.

The board marking MB1136 C-02 corresponds to a board, configured to use ST-LINK MCO 
as clock input.