Microcontroller Solutions TechZone Magazine, April 2011 - Digikey

these can be integrated onto the mostly-digital MCUs, but the vendors
are still working to get closer to more compact and well-blended
with wireless systems. Range, EMI, and security are other issues to
consider in selecting the radio air interface.
In industrial applications, for instance, having wireless
controllers, especially in a mesh network, means that to
move some equipment or add a sensor on a factory floor may
mean just placing the equipment where it is needed. With a
wireless network, no new cables need to be laid out or routers
reconfigured. The network self-discovers the new equipment (and
probably doesn’t care if it was only moved). If a unit fails, it simply
falls off the grid and the rest of the network continues without it,
though hopefully a flag is raised.
Consumer explosion
As mentioned, many forms of communications have become stand-outs
and true standards in recent years. The high volume of digital consumer
electronics has become a significant factor in establishing such
standards. While CAN is more under-the-hood, USB and Ethernet are far
more visible. The phenomenal boom – and churn – in digital still cameras,
MP3 players and cellular phones—in tandem with the desire to transfer
large amounts of data between PCs, TVs, printers, and the Internet—has
caused an explosion in the need for universal connectivity.
This explosion of consumer electronics needing connectivity opened
huge opportunities for chip vendors to supply vast quantities of
chips and programmers to write the protocol stacks to support the
standards. Lower costs and off-the-shelf software made it even easier
to connect consumer devices in more ways.
Microcontrollers will hook you up
Microcontroller vendors have been taking care of your
connectivity and communications needs. More and more serial
channels, communications methods, and networking peripherals have
been brought into the MCU as the market has called for it. Along with
the hardware implementation, the chip vendors have been assembling
the software that makes it work. Third-party software vendors step
up to the plate to offer improved, more universal, customizable,
and specialized communications software and protocol stacks. The
result is a relatively easy and cost-effective means of adding greater
connectivity to MCU-based equipment.
The more advanced communications protocols require more
horsepower from the processor than a little bit-banging does or a
UART. Some can take advantage of additional RAM for buffering
and forming packets. Some can use Direct Memory Access (DMA)
techniques to block-transfer strings of data to other parts of the
system. The more advanced MCUs typically have more advanced
communications capabilities. However, some advanced connectivity
is available on 16-bit and 8-bit MCUs, as well. Most vendors have
evolved with their markets, so your favorite architecture probably
has a selection of MCUs with a peripheral on board to implement the
technology of your choice.
In my opinion, the best bet for exotic network and communications
will be with 32-bit MCUs. They have the performance, the fl exibility,
and the memory space to handle the code, and they are more likely
to be in markets where overall performance is important, and where
connectivity is a must rather than a luxury. This also means the 32-bit
MCUs will keep up with heavy communications traffi c. However, 32-bit
MCUs are not as expensive as one might believe. The price difference
from a comparably-equipped 8-bit MCU is hardly noticeable.
The established architectures have a good range of MCUs with
CAN peripherals. Namely Renesas, Freescale, Texas Instruments,
STMicroelectronics, and Microchip all have suitable solutions for
this market.
When it comes to USB, almost any vendor has a good range of MCUs
with USB connectivity. USB does not weigh down 8-bit MCUs, and
16-bit controllers should handle USB well.
Ethernet has been appearing on MCUs more frequently the last
few years, and has increasing promise as the Internet becomes
a backbone for all things electronic. We are consistently seeing
suppliers provide solutions with both MAC and PHY integrated on chip.
There are a few MCUs containing an array of communications
facilities. To highlight one solution, ARM-based Stellaris line from
Texas Instruments has MCUs with several serial peripherals all
on-chip including: two CAN 2.0 A/B controllers, a USB 2.0 Full-
Speed Host/Device/OTG module, a 10/100 Ethernet MAC/PHY with
hardware-assist to synchronize industrial networks via the IEEE 1588
Precision Time Protocol, two SSI/SPI controllers, two I 2 C interfaces, an
I 2 S interface, and three UARTs.
Is your application suffi ciently connected for tomorrow
Technical and Design Support Services
Digi-Key offers live technical support 24/7 via telephone, e-mail
and live web chat. Digi-Key’s 130 technicians on staff are
trained by manufacturers to answer product-specifi c questions.
Additionally, these technicians cross-reference part numbers,
assist customers in choosing products, research and aid in
selecting new product, and provide access to in-depth productspecifi
c information as well as specifi cations and performance
data on new products.
Digi-Key’s Design Support Services (DSS) team of application
engineers and technicians provides general information and
complimentary project-specifi c assistance. DSS provides service
to engineers ranging from one-time contacts regarding product
recommendations to ongoing prototype-to-production design
support. DSS strives to guide the customer through the design
process while achieving the best solutions and, ultimately,
streamlining the design cycle. The DSS team provides support
and advice on system design, aids with product selection and
development tools, and provides assistance with other applicable
design issues. Additionally, members of the DSS team produce
application notes, webinars and instructional videos. The DSS team
is available from 8:30 a.m.-5:00 p.m. CST via telephone, e-mail
and web-conferencing software.
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