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I have just bought a whole bunch of Xbee Pro S2Bs and Freetronics Eleven boards.

When I set up the XBees in AT mode, the Arduino constantly resets. At least that's what I think it is doing - the D13 LED keeps flashing (3 times in quick succession, once per second) and the sketch won't run.

In API Mode it seems fine, but I want to use AT mode for simplicity - anyone have any ideas why AT mode would be causing the Arduino to reset?

I have already asked this question on the Arduino forum but haven't got anywhere yet ...

http://arduino.cc/forum/index.php/topic,60285.0.html

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Is the Arduino board's regulator rated for the XBee Pro's current draw?

I know Sparkfun had some issues with this, where their XBee -> computer interface board had a 150ma 3.3v regulator, and the XBee Pro needs ~ 215mA.

If the 3.3V regulator is too small, the XBee could be browning-out the local power supply as it tries to power on.


How are you connecting the XBee to the Arduino board anyways? From what I could see looking up the Freetronics board you mentioned, it doesn't have an XBee socket.

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  • \$\begingroup\$ Thanks for your answer. I have since worked out that the XBee works OK in that mode with an earlier version of the Freetronics Board the Twenty-Ten. It's connected using a Sparkfun XBee shield. Now the issue is .. why would it work with the Twenty-Ten and not the Eleven!! They are supposed to be basically the same thing... maybe something to do with the power draw as you suggest. \$\endgroup\$ – Stuart W May 12 '11 at 15:40
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Is this a full serial interface? If so, you might need a pull-up resistor to keep the DTR high - Arduino will reset if it's pulled low (used by the IDE for programming).

More details here: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1213719666/28#28

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  • \$\begingroup\$ Thanks for your answer. I did run out and get some resistors to try this solution but it still didn't work.I have since worked out that the XBee works OK in that mode with an earlier version of the Freetronics Board the Twenty-Ten. It's connected using a Sparkfun XBee shield. Now the issue is .. why would it work with the Twenty-Ten and not the Eleven!! They are supposed to be basically the same thing... \$\endgroup\$ – Stuart W May 12 '11 at 15:40
  • \$\begingroup\$ From the schematics Eleven and Ten - the reset circuit is different because the FT232 has been replaced by the AtMega8U2. Also, it seems on the Eleven the CTS triggers the reset, while on the Ten its DTR. The two are notable different. Have a look at the schematics. Is bridge SJ1 (used to enable/disable the serial/programming reset) open or closed on both? \$\endgroup\$ – RJR May 13 '11 at 1:07
  • \$\begingroup\$ One more thing you can try is to use softserial on different AtMega pins - this would eliminate any issues with the boards serial implementation. \$\endgroup\$ – RJR May 13 '11 at 1:13
  • \$\begingroup\$ Last one - have a look here: arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1217201592/0 \$\endgroup\$ – RJR May 13 '11 at 1:20

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