see attached to the NEMO10 in
Photo 5 is one of a pair of
boards. The NEMO10-to-PICDEM Z
direct serial port connection is
possible because the NEMO10 is a
DTE (Data Terminal Equipment)
device. Your PC is configured as a
DTE device. The PICDEM Z is wired
for DCE (Data Communications
Equipment) operation. Modems
are DCE devices. A DTE device’s
transmit pin is positioned in the
connector to directly connect to
the DCE device’s receive pin. The
same holds true for the DTE’s
receive pin and DCE’s transmit pin.
Add a ground pin to this equation
and you have what is termed the
three-wire serial interface.
Now that we have a device
server to device serial connection,
let’s write a simple piece of code to
spin something out of the PIDEM Z’s
SCREENSHOT 5. This particular
router calls the NEMO10 a virtual
server. You should recognize the
IP address and port numbers,
considering we assigned them.
unsigned int servo = 0;
Printf(“YOU HAVE CONTACTED
SCHEMATIC 1. This is very clever and cheap.
This circuit eliminates the need for a more costly
The Printf statements are not
your normal printf statements. The
Printf and PrintDec are user written
routines that do not accept any of
the normal printf formatting.
Basically, the code snippet runs
forever, sending the incrementing
servo variable message to the
NEMO10’s serial port.
Everything is now in place and
we can perform a preliminary test.
Clicking on the Serial Input/Output
Monitor CONNECT button should
establish a TCP session with the
NEMO10. If our little test program is
running, we should see the message
from the PIC18F4620. I’ve started
the PIC and I can see that the
NEMO10’s serial RX LED is blinking.
PHOTO 5. The PICDEM Z
development board is very useful
when you have to lash together
a simple 802.15.4 network. The
serial port plug-to-plug works
because the NEMO10 is
configured as a DTE and the
PICDEM Z is wired as DCE.
SERVO 10.2012 55