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Xbee Unable to communicate with modem — Parallax Forums

Xbee Unable to communicate with modem

egenrietheregenriether Posts: 29
edited 2013-09-06 03:55 in Accessories
Hi,

I'm trying to use a Propeller professional development board to set up an Xbee to PC link using Serial_Pass_Through.spin and X-CTU software. I have two S1 Xbees. I'm not using a Xbee USB adapter, just the adapter for the pin spacing. I keep getting the same error when I hit the Test/Query button: "Unable to communicate with the modem" The Xbees are unused. I have 3.3V connected to Vcc, Ground connected to Vss and Dout and Din connected to P7 and P6 respectively although I've tried swapping them. I'm not at the loopback test yet, just trying to get a communication with my PC. (I'm using Windows xp on an iMac via VMWare) Here's what I've checked so far:

3.3V on Vcc
Ground connected correctly to Vss
Correct COM port using 9600 Baud
COM port not otherwise busy
Tried both antennas and pin adapters in case one was faulty
Tried changing the pins for DOUT and DIN
Updated USB driver to COM port
Got updates to X-CTU versions

What's happening is weird: If I press the Test/Query button the green Rx light on the PDB blinks twice then it fails to communicate. But if I unplug the DOUT wire to the prop the Tx light comes on. It's as though the pin being connected shorts out the Tx and it fails (though I doubt that's happening). If I leave it unconnected it just keeps trying forever. As soon as I plug it back in it fails to communicate again. Once I got it to say comms with the modem were OK in the midst of plugging and unplugging wires to the pins but I can't replicate that. Any ideas as to what might be wrong?

Thanks,

Brian

Comments

  • FranklinFranklin Posts: 4,747
    edited 2013-09-04 18:20
    On the PC side how are you connecting things? The xbees need 3.3v Max on lines you are connecting. Without some form of level shifting you probably are not doing that.
  • egenrietheregenriether Posts: 29
    edited 2013-09-04 18:42
    Well I'm assuming my problem must be something like what you're referring to. I just have the dev board powered with the normal power supply and the voltage on the xbees is the 3.3v from that. The pc just has a USB cable going to it. What other connections are required? Every tutorial only mentions connecting by USB. They don't mention any power from the pc. Thanks for your reply!
    Brian
  • Martin HebelMartin Hebel Posts: 1,239
    edited 2013-09-05 03:34
    Since writing the text and testing recently, I've not been able to configure or loopback test using serial-pass-through. My apologies and I'll ask Parallax to list it as errata, that this option is not supported.

    Sincerely,
    Martin Hebel
  • egenrietheregenriether Posts: 29
    edited 2013-09-05 05:55
    Martin,

    Thank you much for your reply. Are you getting the same modem error that I am getting? I still don't know if my problem is the object I'm using or my connections/hardware. Any advice on which objects to use to communicate with the computer?

    Brian
  • Martin HebelMartin Hebel Posts: 1,239
    edited 2013-09-06 03:55
    Serial pass through should work fine for sending/receiving from the terminal, just not for configuration changes or test/query and loopback test. I don't know if its a timing issue or what.

    Martin
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