1
\$\begingroup\$

Really quick question here - is it possible to use the GND/5V from the USB cable to power the Arduino through the USB connector but use the RX/TX pins to a motherboard's USB pin headers (D+/D-)?

The D+ = TX
The D- = RX

Then connect the common grounds (5V, GND and motherboard GND together).

So:

5V (psu) ---------> Arduino USB \$V_{cc}\$ connector
GND (psu) --------> Arduino USB GND connector
TX (Arduino pin) -> motherboard USB header D+
RX (Arduino pin) -> motherboard USB header D- 
GND (Arduino pin -> motherboard USB header GND

Will the GND pin on the Arduino be considered "combined" since the PSU GND is connected via the USB connector (grounding both USB GND and motherboard GND)?

The Arduino I am using is this:

Freaduino Micro V1.2

\$\endgroup\$
  • \$\begingroup\$ Well, as of this writing it has been 12 hours sisnce you asked this question and I am the first comment. I think that supports what I am about to say which is: What are you talking about? What motherboard where? My suggestion would be that you will need to provide some more information to get a good answer. \$\endgroup\$ – mikeY Oct 2 '13 at 15:13
0
\$\begingroup\$

It sounds like you want to power the Arduino with a different power supply than the motherboard. This is common for self-powered devices and the device's datasheet will have a section with the recommended schematic for that configuration. The GND will be tied together and IIRC the +5V is used to detect the connection.

You can consult the datasheet and the board's schematic to see whether you can reproduce the datasheet's schematic for self-powered devices with a hacked USB cable.

| improve this answer | |
\$\endgroup\$
1
\$\begingroup\$

If you are talking about http://elecfreaks.com/store/download/Freaduino%20microV1.2.pdf board you can power from USB connector and use serial RX/TX 32u2' 5V serial pins. D+/- are high frequency USB data wires dedicated to USB only. You can make ugly hack, unsolder R3&R10 and wire D+/- to RX/TX. But it's really really awfull reusing USB connector as 5V serial.

| improve this answer | |
\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.