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Issue 27: Rx works fine, Tx does not. Same result even using the unmodified examples.
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Status:  Invalid
Owner:  ----
Closed:  Feb 2014

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Reported by eelmasllari, Mar 21, 2012
What steps will reproduce the problem?
1. open the Series2_Tx example
2. run it
3. Error message: No timely response

What is the expected output? What do you see instead?
I expect the packet to be sent. Instead, nothing gets sent, and the program outputs "No timely response"

What version of the product are you using? On what operating system?
xbee-arduino 0.3 from the zip file; OS Windows 7, Arduino IDE 1.0
Arduino duemilanove with atmega328
XBee Series2 from Digi ( FCC-ID OUR-XBEE2, IC: 4214A-XBEE2
baud rate 9600, 8N1

Please provide any additional information below.
I tried the same xbees in two ways:
1) java api, ftdi cable from computer to xbee, with xbee adapter kit 1.0 from adafruit
2) arduino api, with the standard xbee shield

The java api works fine, the arduino one not. I traced the code to make sure that identical bytes were being sent. Here are the results:
Tracing code from xbee-api and xbee-arduino
in both cases the same request gets sent: 


destination xbee is 13a200 40335473


send from java (xbee-api ZNetSenderExample ) to xbee over ftdi cable: works, packet gets sent and arrives at destination
send from arduino (xbee-arduino Series2_Tx example) to xbee over xbee shield: does not work,    error "No timely response"

send the raw bytes of the above resuest (via many serial.write-s for each byte) from a simple arduino program to xbee over the xbee shield does not work

I made a "proxy" program inside the arduino that connects software serial port to serial port, i.e. makes a "pipe"

void setup() {
  nss.println("starting up...");
  delay(10000); //give xbee time

void loop() {  
  while (nss.available()) {;
 //   nss.print("Wrote ");nss.println(c, HEX);

  while (Serial.available()) {
  while (!(nss.available() || Serial.available())) {

working in AT mode, this pipe works fine. Now I try sending the raw bytes over the pipe in API mode

Raw bytes from the request above:

Sending the raw bytes from computer terminal program (coolterm) over this pipe to the xbee: does not work
sending the raw bytes from computer terminal program (coolterm) over ftdi cable to the same xbee: works fine, packet gets delivered

If I use the Series2_Tx example, but with a broadcast address, packet gets delivered. 

I double checked the address and it is the same in java and arduino. Baud rate is also the same.

Any idea what the reason might be or how to fix it? 
Thanks in advance,
Apr 23, 2012

I have a similar problem with this library. It can never send any data. Although I'm using the new zigbee modules, S2B.

What is the expected output? What do you see instead?
I'm using the Series2_Tx example too. I'm only trying to send a payload like {1,2,3,4} to a specific address, and also a broadcast one, but it doesn't matter, the message never arrives.

What version of the product are you using? On what operating system?
xbee-arduino 0.3 from the zip file; OS Ubuntu 11.10, Arduino IDE 023
Arduino Mega2560 with Xbee Shield
XBee Pro Series2B from Digi ( FCC-ID MCO-PROS2B, IC: 1646A-PROS2B
baud rate 57600, 8N1

Please provide any additional information below.
The receive example works fine, because I have been investigating and messages are shown when they arrived. To do this, I used the x-ctu app, and I send the data by terminal making my own frame, and this frame is received by the api in a right way.

The frame I made was: "7E 00 10 10 01 00 7D 33 A2 00 40 86 15 D9 00 00 00 00 12 34 3F" (It might be the same frame as send example must send).

I'll continue making some probes to try understand where the error is, but if you could help us it would be great.

Thanks in advance.

Apr 23, 2012

In my case the problem was that the XBees need to be initialized to AP=2. the xbee-api (Java) does it automatically, but not the arduino library. It is indeed mentioned in the documentation, yet IMHO not with big enough letters ;) So, before doing anything else, just after xbee.begin, you need to send an ATCommandRequest with AP=2 (careful, the AP will be a char array {'A','P'}, but the 2 in the value is a byte/int, not a char '2'). This worked for me. 

Ciao & good luck,
Apr 23, 2012


The Xbees are setted by X-CTU to AP2, so in my case it isn't necessary, although I will try it.

I was checking the library and in the XBee.cpp, at 'sendByte' function I substituted the 'write' instructions for 'Serial.print(xxx, HEX)', where xxx are 'ESCAPE', 'b^20' or 'b'. And it shows the frame to send, but this frame is wrong (I know that when a byte is '00', it only shows one '0'). 

I couldn't tell you if it because of the 'Serial.print' instruction this wrong behaviour, but how I told you before if I send the frame manually, the mesage is delivered to the receiver (in my case the coordinator).

Apr 24, 2012

I've been doing more attempts today. I modified the 'send' function when it adds '2' to the frame length because the didn't be equal as the length of my frame. But it doesn't matters it didn't work yet.

So, I was looking for another thing, and I did the next things:
- I was sending data in AT mode and the coordinator received it in api mode (AP2).
- Instead an arduino mega2560 I used an arduino UNO, but the behaviour was the same as in the mega ones.
- I tried to send the data in the API mode (AP2), and received it by coordinator in AT mode, but coordinator didn't get anything.
- And, finally, I checked if it could be because of the serial. How I did this? Ok, I switched the jumpers to USB mode, and tried again to send data by terminal (x-ctu). It worked! Coordinator get the message. But when I switched back the jumpers to XBEE mode, the router didn't send anything once more.

I'm using the examples in the xbee library for API modes, and for AT modes I only printed the next message: Serial.print("HELLO");

So, it wouldn't be because of the serial. But I don't know what more to try. Also I updated the ZB modules firmwate, but they don't work yet.

Apr 25, 2012
I am running out of suggestions, but if I were in this position, I'd go back to the beginning and trace my steps in the the following order:

-reset everything to AT mode, 9600 bps
-check that things are working in AT mode, no api library needed for this
-switch the node (NOT the coordinator!) to API, check that xbee-api library in Java works. How you connect from Java to the XBEE depends on what cables and electronic skills you have. Worst case, remove the controller chip from  one of the arduinos; this will turn the arduino into a basic FTDI cable (google to find more details)
-switch the coordinator to API, AP=2, check that everything is working -- again only xbee-api library in Java, from the same author as xbee-arduino
-in the library, go to "private void doStartupChecks()" in and comment out the part that reads and sets the AP=2 mode. Run and check that everything still works. 
-if everything is fine up to here, you may start using the xbee-arduino library. double-check to make sure the serial ports in the code and in the XBees are set to 9600 bps. use a hardware serial port, not a software serial one.
hopefully it should work at this point. if it doesn't, you might need an oscillator to see what is being sent to the xbees and compare it with what should be sent. I used this one when I had problems:

Good luck!
May 4, 2012

it doesn't work.
I can't find a solution, so if somebody could try it and post his/her solution it would be great!


May 11, 2012
In 'sendByte' function, when the it calculates the checksum it has to be:
"checksum = 0xff - (checksum & 0xff);"

But communication still fails!
Feb 2, 2014
Project Member #9
Could not reproduce
Status: Invalid
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