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I am attempting to power on a Texas Instruments Tiva TM4C123GH6PM with an external power supplied by the VCC pin from a generic ESC.

In the board, there is a non-soldered pin named VBUS which I wonder is available for this purpose. So the question is this point: Can I connect my VCC/GND pins from the ESC into the Tiva so the board will work out? I did not find it very clear in Tiva's datasheet.

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  • \$\begingroup\$ Where does that signal go on the schematic? Unless the device is intended to be powered by a USB host, probably not to its power rails - it may either be ignored or only be sensed to detect if there is a host connected. \$\endgroup\$ – Chris Stratton Jul 23 '14 at 16:56
  • \$\begingroup\$ It depends on what you are talking about. You cannot use IC VBUS pin to power your device but you can use Tiva Launchpad VBUS pin to do so. I find your question lacking information. \$\endgroup\$ – Maciej Kucia Jul 30 '14 at 7:15
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there is a detail from this documentation, provided by Texas Instruments.

enter image description here

In the final pages of this document are the circuit diagrams of the device. As you can see in detail, + VBUS connection is taken from the ICDI section or from the USB connection associated to the microcontroller.
This means that you can select with the switch, the source of power supply, from emulation block or from the external USB.
Then, the voltage level +VBUS enters a + 3.3V regulator that feeds the microcontroller. In short, you can connect an external source of 5V on the +VBUS pin, but you must be careful not to connect power from the emulator block, to avoid conflicts.

You may need to adapt your application allowing you to select the external power supply (through the VBUS pin) or from block emulation, to monitor the implementation of the software in the hardware implementation.

Note
It is very important that the two GND pins are connected when using external power.

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  • \$\begingroup\$ Martin, I have to power a Tiva Launchpad externally, what do you mean with "the two GND pins are connected"? \$\endgroup\$ – user96499 Jan 8 '16 at 14:48
  • \$\begingroup\$ The board has two 20 pin connectors (IDC). There is a GND pin on each connector. Take care of the supply selector switch. \$\endgroup\$ – Martin Petrei Jan 8 '16 at 18:08

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