iOS Sensor Apps with Arduino

Configuring Two XBee Radios

We’re now going to configure two XBee radios as a straight cable replacement. In other words, the first will be configured to send messages to the second, and vice versa.

Go ahead and plug the first of the two radios into your Mac, and place it into command mode, as in the previous section, by sending a +++ to the appropriate serial port from your terminal program.

The first thing we need to do is set the baud rate. When in configuration mode, enter ATBD. You should get a number between 0 and 7 returned, as below:

ATBD
3

This number indicates that the radio is set to 9,600 baud. We’ll leave our radio at 9,600 baud for now. However, if you wanted to set the radio to a different baud rate, you’d issue the command ATDBn, where n was a value corresponding to the baud rate you wanted from Table 5-1.

Table 5-1. The value returned by the ATBD command and corresponding baud rate

ATBD Value	Baud Rate
0	1200
1	2400
2	4800
3	9600
4	19200
5	38400
6	57600
7	115200

So, for example, to set our radio to 57,600 baud, we’d issue the command ATDB6:

ATBD6
OK

We can then check the baud rate has been set, by again issuing the ATBD command. This time it should return a six:

ATBD
6

Having set the baud rate, we need to go ahead and similarly set the PAN ID using the ATID command, the node address using the ATMY command, and the destination node address using the ATDL command. Finally, we need to commit our changes by issuing a write command, ATWR, to save our settings.

Therefore, for the first of our two ...