UM1974 Datasheet, PDF (22/62 Pages) List of Unclassifed Manufacturers – STM32 Nucleo-144 board

Hardware layout and configuration
UM1974
6.5
Push buttons
B1 USER: the user button is connected to the I/O PC13 by default (Tamper support, SB173
ON and SB180 OFF) or PA0 (Wakeup support, SB180 ON and SB173 OFF) of the STM32
microcontroller.
B2 RESET: this push button is connected to NRST and is used to RESET the STM32
microcontroller.
6.6
JP5 (IDD)
Jumper JP5, labeled IDD, is used to measure the STM32 microcontroller consumption by
removing the jumper and by connecting an ammeter.
• JP5 ON: STM32 is powered (default).
• JP5 OFF: an ammeter must be connected to measure STM32 current. If there is no
ammeter, the STM32 is not powered.
In order to get a correct current consumption, Ethernet PHY should be set in power down
mode or SB13 should be removed. Refer to Section 6.10: Ethernet for details.
6.7
6.7.1
OSC clock
OSC clock supply
There are four ways to configure the pins corresponding to 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
PF0/PH0-OSC_IN of STM32 microcontroller. The following configuration is needed:
– SB148 OFF
– SB112 and SB149 ON
– SB8 and SB9 OFF
• HSE oscillator on-board from X3 crystal (not provided): for typical frequencies and
its capacitors and resistors, refer to STM32 microcontroller datasheet and to the
AN2867 for 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 following configuration is
needed:
– SB148 and SB163 OFF
– SB8 and SB9 soldered
– C37 and C38 soldered with 4.3 pF capacitors
– SB112 and SB149 OFF
• Oscillator from external PF0/PH0: from an external oscillator through pin 29 of CN11
connector. The following configuration is needed:
– SB148 ON
– SB112 and SB149 OFF
– SB8 and SB9 removed
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