Power Supply And Power Selection; Figure 9. St-Link Connections - STMicroelectronics UM1079 User Manual

Hardware and layout
4.3

Power supply and power selection

The power supply is provided either by the host computer through the USB cable, or by an
external 5 V or 3.3 V power supply.
The D1 and D2 protection diodes allow to use the EXT_5V and EXT_3V pins independently
as input or output power supplies (see
• EXT_5V and EXT_3V can be used as output power supplies when the application
board is connected to pins P1 and P2. In this case, the EXT_5V and EXT_3V pins
deliver a 5 V or 3 V power supply and power consumption must be lower than 100 mA.
• EXT_5V and EXT_3V can also be used as input power supplies when the USB
connector is not connected to the computer. In this case, the power of the board must
be provided by a power supply unit or by an auxiliary equipment complying with
standard EN-60950-1: 2006+A11/2009. This power source must be Safety Extra Low
Voltage (SELV) with limited power capability.
Battery powered (optional)
The 32L152CDISCOVERY board has been designed to run from a CR2032 standalone
battery (no connection with USB or other power supply is required).
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Figure 9. ST-Link connections

Figure 3):
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UM1079