Hardware layout
UM1690
14/27
UM1690 Rev 3
5.2
Power supply and power selection
The power supply is provided either by the host PC through the USB ST-LINK or USB
USER connector, 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, for instance when the USB connector is
not connected to the PC.
In this case, the STM32F072 Discovery kit 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.
5.3 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: This red LED indicates that the board is powered.
•
User LD3: This red user LED is connected to the I/O PC6 of the STM32F072RBT6.
•
User LD4: This orange user LED is connected to the I/O PC8 of the STM32F072RBT6.
•
User LD5: This green user LED is connected to the I/O PC9 of the STM32F072RBT6.
•
User LD6: This blue user LED is connected to the I/O PC7 of the STM32F072RBT6.
5.4 Pushbuttons
B1 USER: User and Wake-Up button connected to the I/O PA0 of the STM32F072RBT6.
B2 RESET: The push button connected to NRST is used to reset the STM32F072RBT6.