Simple Loopback setup not working.

PlusOn3 · 2011-12-08 17:04

Hey guys, I know this should go in the wireless forum list, but I put it there and haven't gotten any reply yet. And I have had much better results from this forum. And I know this is a really simple question, but I am embarrassingly new to all of this.

I recently purchased a couple of XBee modules (http://www.parallax.com/Store/Accessories/CommunicationRF/tabid/161/CategoryID/36/List/0/SortField/0/catpageindex/2/Level/a/ProductID/638/Default.aspx)
with the appropriate adapter boards.

I am just getting started in trying to figure out how to work with them and I can't get very far. I bought the "Getting Started with XBee RF Modules" book to help me learn about them. I have set up on my propeller breadboard an XBee module with a serial pass through code I copied out of the book. I attached a word document with the code in it.

serialpassthrough.rtf

I have the XBee chip set up on the propeller breadboard and when I connect a battery the LED I connected for power indicator lights up. I have attached an image of the setup here.

When I am in the X-CTU software I can a positive connection when I test it. But when I go to the terminal and start typing there is not response text.

I also have the loopback XBee module setup on the same breadboard on the opposite side (I don't know if that is the issue). I have also attached a picture of that setup. And when I connect a battery I get my power LED to light up here as well.

I'm not sure what I am doing wrong but I am sure it is probably something simple. Any help would be great.

Thanks,
Tyler

StefanL38 · 2011-12-09 07:03

Hello Tyler,

welcome to the propeller-forum.

To narrow down the problem you have to go back to a "working system". hm how to do that.

simply be re
cing possiblebugsources as much as possible.
First step: testing the PC-terminal connectiod

CON
  _clkmode = xtal1 + pll16X
  _xinfreq = 5_000_000

  XB_Rx         = 0
  XB_Tx         = 1
  XB_Baud       = 9600

  PC_Rx         = 31
  PC_Tx         = 30
  PC_Baud       = 9600

VAR

  long stack[50]

OBJ
  PC    : "FullDuplexSerial"

PUB Start
  PC.start(PC_Rx, PC_Tx, 0, PC_Baud)

  repeat
    PC.str(string("Hello World",13))
    WaitCnt(ClkFreq + cnt)

if this works connecting the XBee-serial receive-pin with the PC send-pin and vice versa through WIRES
testing it with the loop-back code

If this works it is something with the XBees

Next step testing two serial PC-sports with a nullmodem-cable
if this works insert Xbees between them. This might requiere voltage-levelshifters as a standard-PC-port has +-12V and the xbee might have 5V or 3.3V

The method behind all this is go back to very basic systems that are well known as working. Insert just one possible bug-source to check if this is the bug or it is working

keep the questions coming
best regards

Stefan

Simple Loopback setup not working.

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