another MRF24J40MA data radio. To
keep the sensor-generated bits from
piling up in the bit bucket, I’ll attach
the remote PIC18F4620 to a device
That’s what I said. A device
server is an electronic module that
accepts a non-IP-based protocol and
formats the data represented by the
protocol into an addressable IP-based
protocol that can travel on a LAN, a
WAN, or the Internet. In our design,
the non-IP protocol will begin with a
START bit followed by eight data bits
and a STOP bit. If you added NO
PARITY to the aforementioned data
stream, you correctly identified our
mystery protocol as RS-232. Thanks to
the PIC front end, our device server
can accept any serial protocol that can
be represented in byte format. The
device server of choice is offered by
the SENA Corporation and is called
NEMO10 is billed as a single-chip
network enabler module. A glance at
Photo 1 seems to prove that out.
Actually, NEMO10 is a multi-chip
serial-to-Ethernet converter housed in
a compact DIL configuration.
NEMO10 is composed of an 8032
microcontroller, 256 KB of static RAM,
program Flash, 64 KB of EEPROM, and
a NIC (Network Interface Controller).
The NEMO10 is network-ready
because it is shipped with a unique
burned-in MAC address. The only
networking hardware component
missing is the Ethernet magnetics
module. The NEMO10 is designed to
interface with the XFMRS, Inc.,
magnetics/filter combo module which
is under the lens in Photo 2.
Like many of today’s modern
microcontrollers, the NEMO10’s UART
is indigenous to the microcontroller’s
silicon. In addition to the Ethernet and
PHOTO 1. The NEMO10 is a compact serial-to-Ethernet converter module
designed to interface any RS-232-based device to a LAN or the Internet.
serial interfaces, the NEMO10 provides
all of the necessary I/O drive for
Using ARP, NEMO10 can resolve
hardware (MAC) addresses using
known IP addresses. The NEMO10’s
ability to act as an ICMP client allows
it to respond to a network ping.
NEMO10 can request an IP address
from a DHCP server and communicate
via Telnet. NEMO10 can request an IP
address, which infers that it may be
able to perform other IP-based client
and server functions using IP’s best
buddy, TCP. In fact, the NEMO10 can
be configured as a TCP client, a TCP
server, or a combination of both.
PHOTO 2. You'll need this baby on the other side of the NEMO10 which is
designed to interface to Ethernet devices using this XFMRS, Inc., Ethernet
magnetics module. There's also a pair of homemade headers in this shot.
You'll find out why one is missing a pin later on.
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