I'm working on a project with the STM32F407 discovery board. My question is related to powering the board from external source. In the datasheet, it is specified that power can be provided either by USB through a host PC or through external power supply if USB is not connected, using the 5V or 3V pins.

My question is the following:

Can I use the USB port to power the board from a cell phone adapter that can output 5V/2A?

It is possible to power the board by this adapter (5V/2A) through the 5V pin without causing any harm?

this image is taken from the board's user manual

  • \$\begingroup\$ Yes and yes. At least, according to the screenshot. \$\endgroup\$
    – Eugene Sh.
    Jul 13, 2015 at 14:45
  • \$\begingroup\$ There is a diode on the board that will blow if you try to pull more than 100mA (I think) from the USB regulator circuit. You can buy a better diode, of course. It is not difficult to replace. \$\endgroup\$
    – Mewa
    Jul 13, 2015 at 19:00

1 Answer 1


From STM32F4DISCOVERYDiscovery kit with STM32F407VG MCU

Board power supply: through USB bus or from an external 5 V supply voltage

USB provides power during programming. This can be replaced by a charger only USB or separate 5V power connected to P2.

STM32F407 Discovery Board Pin Outs STM32F407 Discovery Board 5V USB

  • \$\begingroup\$ thank you StainlessSteelRat for the answer Does this means it is safe to connect the 5V cell phone adapter (usb mini-B ) to the to the usb port (cn1 ) of the board to power it with no harm ? or that i'd better cut the adapter's "mini-B" connector and connect the wires directly to the P2 5V pin ? \$\endgroup\$ Jul 15, 2015 at 14:20
  • 1
    \$\begingroup\$ Yes. Either will work for running. I've used both with no problems. Diode allows mini-B to be used for programming if external 5V source is used. Sorry for size of graphics. \$\endgroup\$ Jul 15, 2015 at 20:20

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