Let’s run a stand-alone
configuration next. Here, we
remove the Experimenter from
the PC USB, but retain the RF
carrier board with the preconfigured RN-XV module from
our previous experiment. We
then add an Experimenter color
display carrier module and a
PS/2 keyboard interface (this
carrier module is available from
the Nuts & Volts Webstore).
This new configuration acts
as a self-contained Wi-Fi device
(with the use of a PC), and can
interact with the PC or other
Wi-Fi devices as a stand-alone.
We will need to configure the
Experimenter software again.
Navigate with MPLAB X to the Wi-Fi demo folder and
open the project software “lab3.X.” Program the
Experimenter as before with the PICkit 3 and then remove
it. Connect a PS/2 keyboard to the color display carrier
module; you should see the Experimenter automatically
associate with the access point and receive its IP address.
In this specific example, the RN-XV IP is 192.168.1.6 with
a default port number of 2000.
The IP address is the routable network address of the
device tied to the network, but what is the port number?
Port numbers provide access to a host device application
that uses the IP address. The port number is a 16-bit
Figure 7. The stand-alone configuration showing the association complete
and the IP address assigned.
unsigned integer (1 to 65535; 0 is reserved). Because of
the limited size of the display (only 20 characters by 15
rows and a 5x7 character font), there is some wrap-around
The display will automatically pause once it fills up the
screen. You’ll need to type a (CR) on the keyboard to see
the rest of the display when this happens. You are now in
business to conduct any RN-XV experiment.
Let’s move on to our TCP exercises by entering
command mode (type “$$$”).
to the Host
In command mode, we will
open a TCP connection to the host
computer, and then pass TCP
messages to the remote PC by
simply typing on the PS/2
keyboard. This exercise is generally
representative of a remote sensor
application. Also keep in mind that
a TCP connection is a one way
communication (see Figure 8).
44 March 2013
Figure 8. Sending data from the Experimenter
to the PC using TCP.