My Mac running the Arduino IDE does not accept the control-Z command to configure the board. I don’t know why, but I did find a way to configure the board with the Mac. In case anyone else has this problem, here is how I solved it. I used the TERMINAL program that comes with OSX. You will need to know the name of the port your Mac is using for the board. You can get this by running the Arduino IDE and pulling down the “Tools” menu. Look at the “Serial Port” item in that menu and the port name will appear there. When the program starts running, type this code (be careful to use the correct case for the letters and put in a space between the “screen” command and the first “/”):
screen /def/the rest of the port name you get from the Arduino IDE “Tools” menu
Press Return. The screen will go blank for an instant and then you will see the data from the board appear. Now you can enter control-Z. I had to type it a couple of times because the data is coming in so fast (the default setting is one data set each 2 seconds) that the serial port is busy handling the incoming data for a lot of the time. You have to find a gap when the port is idle so that it can “hear” your control-Z. When it does hear the command, the configuration menu appears and you can proceed exactly as described in the SparkFun data sheet.