You have to read from the serial right after you send the +++ command, because this is where the xbee writes 'OK'. Also a better way to respect the guard times is to wait for a reply, and test to see if it is 'OK'.
Here is my code, I don't remember if it was working the last time I checked but I will just paste it here and you can modify it as you like. All it does is broadcast A1, B2, C3, etc.
There's a lot of commenting out where I was experimenting, but the regular comments are informative. Make sure you go through it step by step, it's quite simple when you get your head around it. Don't forget to change the destination address low to 0xFFFF if you want to broadcast.
In the end you'll come to the same realisation I did that AT mode is not suitable for configuring the xbee by writing programs.
For example I had an xbee constantly transmitting the number '2', and when another xbee was entering command mode using this code, it would receive the number 2 from the remote xbee when it should have received the 'OK' message from the local xbee, thus the program didn't acknowledge it being in command mode and breaking. When entering command mode you'd think an xbee would turn it's receiver off, but that's not the case so you can easily get into trouble.
If you want to do it the right way, have a look at API mode. I have series 1 xbee's so I'm implementing the Digimesh protocol, which so far I haven't seen anyone online do, but it's almost identical to the Zigbee so it's easy. If you'd like I can give you my code for that which can serve as a simple example.
/*
unicast_configure
Configure an XBee for unicast transmission and transmit
some characters to test
*/
#include <SoftwareSerial.h>
// Pins on Bees Shield:
SoftwareSerial xbee(2, 3); // TX, RX
boolean configured;
char c = 'A';
boolean configureRadio() {
// Set the data rate for the SoftwareSerial port:
xbee.begin(9600);
// Put the radio in command mode:
Serial.write("Entering command mode\r");
delay(1000);
while(xbee.available()>0) {xbee.read();}
xbee.write("+++");
while(xbee.available()>0) {xbee.read();}
//delay(1000);
//while(xbee.available() > 0) {Serial.write(xbee.read());}
String ok_response = "OK\r"; // The response we expect
// Read the text of the response into the response variable
// This satisfies the guard time by waiting for the OK message
String response = String("");
while (response.length() < ok_response.length()) {
if (xbee.available() > 0) {
response += (char) xbee.read();
}
}
Serial.println("response1: " + response);
// If we got received OK, configure the XBee and return true:
if (response.equals(ok_response)) {
Serial.println("Enter command mode successful");
// Restore to default values:
Serial.println("Restoring default values before making changes");
xbee.write("ATRE\r");
Serial.println("Setting addr high");
xbee.write("ATDH0\r"); // Destination high
//while(xbee.available() > 0) {Serial.write(xbee.read());}
Serial.println("Setting addr low");
xbee.write("ATDL1\r"); // Destination low-REPLACE THIS
//while(xbee.available() > 0) {Serial.write(xbee.read());}
Serial.println("Setting MY address");
xbee.write("ATMYFFFF\r");
// Apply changes:
Serial.println("Applying changes");
xbee.write("ATAC\r");
/*
///////////////////////////////////////////////
// Write to non-volatile memory:
// Use similar technique as above to satisfy guard time
Serial.write("Saving\r");
xbee.write("ATWR\r");
String response2 = String("");
//while (xbee.available() > 0) {Serial.write(xbee.read());}
while (response2.length() < ok_response.length()) {
if (xbee.available() > 0) {
response2 += (char) xbee.read();
}
}
Serial.println("response2: " + response2);
if (response2.equals(ok_response)) {
Serial.println("Save successful");
}
else { Serial.println("Save not successful");
return false;
}
// And reset module:
Serial.println("Resetting");
xbee.write("ATFR\r");
///////////////////////////////////////////////
*/
Serial.write("Exit command mode\r");
xbee.write("ATCN\r"); // Exit command mode
//while(xbee.available() > 0) {Serial.write(xbee.read());}
Serial.write("Finished\r");
return true;
} else {
return false; // This indicates the response was incorrect
}
}
void setup() {
Serial.begin(9600); // Begin serial
configured = configureRadio();
}
void loop() {
// Test transmission:
if (configured) {
xbee.print(c);
Serial.print(c);
c = c + 1;
if (c > 'Z') { c = 'A'; }
}
else {
Serial.println("Not configured (in loop)");
delay(5000);
Serial.println("Retrying configuration");
configured = configureRadio();
}
delay(1500);
}
