bandwidth messages over very short distances. PAN
message traffic can exist between peer nodes, or the PAN’s
tiny messages are routed to a central location.
In the discussion that follows, we will examine and
exercise the capabilities offered to us by the 802.15.4
specification. Instead of building up an application-specific
piece of PAN hardware, we’ll generate some 802.15.4 PAN
traffic using an off-the-shelf development kit from
Microchip. The idea is to show you how 802.15.4 works
with a very basic PIC microcontroller implementation that
you can use as a reference design to build your own PAN
The Microchip MRF24J40MA
IEEE 802.15.4 2. 4 GHz
FIGURE 1. No rocket science here. This is a standard SPI hookup.
In fact, if you recall our recent ZeroG discussion, this is almost
identical to the SPI interconnect between a PIC and the ZeroG
As its name implies, the MRF24J40MA 2. 4 GHz
transceiver module is an 802.15.4 compliant RF transceiver.
In that the MRF24J40MA is based on 802.15.4, it can
natively support ZigBee and the numerous proprietary
802.15.4-based wireless network protocols such as
Microchip’s Mi Wi and Mi Wi P2P. Like the majority of
802.15.4 radio equipment, the MRF24J40MA transceiver
uses the unlicensed 2. 4 GHz frequency band and has
enough output power to reach out and touch other
802.15.4 nodes at up to 400 feet.
Note: NP = Not Placed.
Here’s a schematic of the
MRF24J40MA module. It’s
good to be able to get a
low-level feel of a device,
even though most of the
details are transparent to
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