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Xbee problem — Parallax Forums

Xbee problem

Rich103Rich103 Posts: 2
edited 2013-03-11 21:10 in Accessories
I am using an Xbee s1 with a 5V/3.3V adaptor. However, the TX led on the adaptor is constantly lit, what could be the problem. Additionally, I can transmit to it and I can see the RX led light up but no transmission from the S1. Please advise.

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2013-03-11 09:12
    How about posting your source code and a description of what I/O pins are connected to which pins on the adapter (or a schematic)? Do you have the xBee installed correctly?

    attachment.php?attachmentid=78421&d=1297987572
  • Rich103Rich103 Posts: 2
    edited 2013-03-11 11:13
    We have used the Xbee in other projects and it worked OK. I have attached a schematic of our application.
    pdf
    pdf
    Xbee #1.pdf
    217K
  • Mike GreenMike Green Posts: 23,101
    edited 2013-03-11 21:10
    It looks like you damaged the xBee Adapter by hooking it up to a MAX232. The xBee Adapter is made to connect an xBee, which is a 3.3V device, to a 5V logic device. The Adapter has a 3.3V regulator on it to drop the 5V supply to the 3.3V that the xBee uses. It also has a buffer (74LVC244A) that accepts 5V signals and produces 3.3V signals for the xBee. It also takes 3.3V signals and buffers them for 5V devices (although only goes to 3.3V which is acceptable for 5V devices). The MAX232 is a 5V device that produces and accepts RS232 signals which can range from -6V/+6V to as much as -15V/+15V. These RS232 signals are also inverted with respect to the 5V logic signals. In any event, the MAX232 won't work with the xBee Adapter and it may damage it since the Adapter's buffer is not designed to withstand negative signals less than about -0.5V.
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