ST Nucleo-64 STM32U3 User Manual page 23

USB_USER is the DC power source coming from the 5 V of the USB Type-C
selection (JP3) must be on pins [9-10] and must be connected as shown in
USB user
connector
(CN3)
External 3V3 power supply input. In some situations, it is interesting to use an external 3.3 V source on the 3V3
input (CN6 pin 4, CN7 pin 16), for instance in case the 3.3 V is provided by an extension board. When the
Nucleo-64 is powered with only a 3.3 V source, STLINK-V3EC is not powered thus programming and debugging
are unavailable.
When using the 3V3 input, the STLINK-V3EC part is not supplied
For this configuration, it is recommended to remove SB8 to avoid backward voltage to 5V through U15.
VDD power supply input. In some situations, it is interesting to use an external power source from 1.71 to 3.6 V
to power only the MCU power supply pins (JP5 pin 2 or JP4 pin 2). In this configuration, external functions like
debug, LED, or expansion connector are not powered. This option can be used to optimize MCU power
consumption measurement.
UM3062 - Rev 2
Figure 14. 5V jumper selection JP3[9-10]: USB USER power source
®
connector (CN3). The 5V jumper
Figure
STM32
microcontroller
UM3062
Hardware layout and configuration
14.
5V LED
(LD3)
USB user
selection
(JP3 [9-10])
USB user
5V LED
(LD6)
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