Hardware — From the Beginning
We have full access to the slave device which, in this
case, will be the Moray Wi-Fi module you were
introduced to last month. So, we know what the Moray
wants to hear and how the Moray will respond. As you
can see in Photo 1, the Moray is a self-contained
embedded Wi-Fi platform. Power and serial connectivity is
provided via the Moray’s integrated FTDI USB interface.
Our host microcontroller does not have native USB
host support in its arsenal, so we will have to get our serial
signal into the Moray the old fashioned way. To do this,
we will have to perform some surgery. However, before
we start cutting traces, we will make sure that we have all
our ducks in a row on the microcontroller side of the
creek. We can line up our duckies by emulating the
Moray signals with a terminal emulator.
The microcontroller mouthpiece hardware design is as
THE DESIGN CYCLE
A Blueprint for Embedded Wi-Fi
■ BY FRED EADY
72 March 2015
Let's face it. You are a Nuts & Volts reader
because you compute. You compute with a
PC that utilizes large microprocessors,
spinning disk drives, and megabytes of
memory. You also compute with
microcontrollers and relatively small
amounts of memory. Each compute
platform has a mission. Normally, the larger
PC platform is used to craft smaller
microcontroller-based solutions. Once the
microcontroller application is spawned, the
larger mothership compute platform is
jettisoned. The microcontroller hardware
then assumes all responsibilities of the
resultant application. We have become
accustomed to having the target
microcontroller perform the bulk of the
application activity. However, the paradigm
is changing. Smart peripherals are assuming
communications, control, and sensing
functions that were normally relegated to
the microcontroller in charge of the
application. In these cases, the
microcontroller becomes a simple
mouthpiece that shouts out commands to
the attached smart peripheral. The smart
peripheral performs the work and reports its
results to the requesting microcontroller. As
a result, the microcontroller does not have
to be endowed with a huge amount of
compute resources. In this installment of
Design Cycle, we will create a bit of
mouthpiece microcontroller hardware
supported by C application code generated
by the CCS C compiler.
■ Photo 1. The Moray is based on the AMW006 Numbat
Wi-Fi module. All of the support needed to communicate
with the Numbat can be found on the Moray
printed circuit board.
