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6.7.2
OSC clock supply
There are four ways to configure the pins corresponding to the external high
‑
speed clock (HSE):
HSE: on-board oscillator X3 crystal (Default: not connected)
For typical frequencies, capacitors, and resistors, refer to the STM32 microcontroller datasheet. Refer to the
application note
Oscillator design guide for STM8AF/AL/S, STM32 MCUs and MPUs
(
). The X3 crystal
has the following characteristics: 16 MHz, 8 pF, 20 ppm. It is recommended to use NX2016SA_16MHz_EXS00A-
CS07826 manufactured by NDK. The following configuration is needed:
•
SB47 and SB49 OFF. PH0/PH1 is not connected to CN11 as I/O.
•
SB48 (MCO) OFF
•
SB4 and SB5 ON are connected to external HSE.
MCO from STLINK-V3E (Default: not connected):
MCO output of STLINK-V3E MCU is used as an input clock. This frequency cannot be changed. It is fixed at 8
MHz, and connected to PH0 OSC_IN of STM32 microcontroller. The following configuration is needed:
•
SB47 OFF and SB49 ON. Only PH1 can be connected to CN11 as I/O.
•
SB48 ON. MCO is connected to PH0 and R5 on the STLINK-V3E side must be connected to provide the
MCO to STLINK-V3E output.
•
SB4 and SB5 OFF. External crystal is not connected to HSE.
External oscillator (Default: not connected)
The input clock comes from an external oscillator through PH0, CN11 connector pin 29. The following
configuration is needed:
•
SB47 and SB49 ON. PH0/PH1 is connected to CN11.
•
SB48 OFF. MCO is not connected to PH0.
•
SB4 and SB5 OFF. External crystal is not connected to HSE.
HSE not used (Default configuration)
PH0 and PH1 are used as GPIOs instead of clocks. The following configuration is needed:
•
SB47 and SB49 ON. PH0/PH1 is connected to CN11 as I/O.
•
SB48 OFF. MCO is not connected to PH0.
•
SB4 and SB5 OFF. External crystal is not connected to HSE.
6.8
Reset sources
The reset signal of the Nucleo board is active LOW and the reset sources include:
•
The RESET button B2
•
The embedded STLINK-V3E
•
The CN8 ARDUINO
®
-included Zio connector pin 5
•
The CN11 ST morpho connector pin 14
UM2861
Reset sources
UM2861
-
Rev 2
page 27/49