Power Supply And Power Selection; Leds; Pushbuttons - ST STM32F401 User Manual

Hardware layout
4.3

Power supply and power selection

The power supply is provided either by the host PC through the USB cable, or by an
external 5 V power supply.
The D1 and D2 diodes protect the 5 V and 3 V pins from external power supplies:
•
5 V and 3 V can be used as output power supplies when another application board is
connected to pins P1 and P2.
In this case, the 5 V and 3 V pins deliver a 5 V or 3 V power supply and the power
consumption must be lower than 100 mA.
•
5 V can also be used as input power supplies, e.g. when the USB connector is not
connected to the PC.
In this case, the STM32F401 Discovery board must be powered by a power supply unit
or by an auxiliary equipment complying with standard EN-60950-1: 2006+A11/2009,
and must be Safety Extra Low Voltage (SELV) with limited power capability.
4.4

LEDs

• LD1 COM:
LD1 default status is red. LD1 turns to green to indicate that communications are in
progress between the PC and the ST-LINK/V2.
•
LD2 PWR:
The red LED indicates that the board is powered.
•
User LD3:
The orange LED is a user LED connected to the I/O PD13 of the STM32F401VCT6.
•
User LD4:
The green LED is a user LED connected to the I/O PD12 of the STM32F401VCT6.
• User LD5:
The red LED is a user LED connected to the I/O PD14 of the STM32F401VCT6.
•
User LD6:
The blue LED is a user LED connected to the I/O PD15 of the STM32F401VCT6.
•
USB LD7:
The green LED indicates when VBUS is present on CN5 and is connected to PA9 of
the STM32F401VCT6.
•
USB LD8:
The red LED indicates an overcurrent from VBUS of CN5 and is connected to the I/O
PD5 of the STM32F401VCT6.
4.5

Pushbuttons

•
B1 USER:
User and Wake-Up button connected to the I/O PA0 of the STM32F401VCT6.
•
B2 RESET:
The pushbutton connected to NRST is used to RESET the STM32F401VCT6.
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