eTech3

eTech3
e
YOUR ELECTRONICS MAGAZINE ISSUE 3
DON’T
KEEP YOUR
BRILLIANCE
TO YOURSELF
DesignSpark is a new online gateway connecting electronic design
engineers like you with the latest information and resources. Join the
growing band of members to exchange ideas, share expertise, make
contacts, grow your network and, of course, unleash that brilliance.
06
Online & On time
Design tools are evolving to increase
the productivity of engineers
www.designspark.com
POWERED BY
rswww.com/electronics
New left and right hand plugs
New left and right hand plugs have been added to Tyco Electronics’ line of
wire-to-board, Eurostyle terminal blocks. This product extension provides additional
configurations of wire access angles to the standard 3.5mm and 3.81mm vertical and
right angle headers. Specific applications of this product include control, input/output
and field wiring.
We’ve added over 4,000 Vishay products,
giving you an ever expanding choice.
A key feature of the plugs is their multiple wire access angles which mate with 90° and 270°
header interfaces. Their rising, screw clamp orientation mates to industry standard open and
closed end headers on the same centerline spacing. In addition, they are
end-to-end stackable without loss of centerline spacing.
The plugs are UL recognized and serve the industrial control, communication equipment,
and HVAC control markets. Other product options include custom marking, printing and
color selection.
rswww.com/Tycoelectronics
TE (logo) and Tyco Electronics are trademarks of the
Tyco Electronics group of companies and its licensors.
rswww.com/vishay 08457 201201
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06
e
16 The futur
We’ve all wasted hours searching through the myriad of online
information. The profusion of internet sites available, for both our
professional and personal needs, inevitably means our online
experience can range between the good, bad and the ugly.
As engineers, we now spend more of our design time online than ever. Whether it’s
connecting with other engineers, sharing information, or seeking new tools to help us
speed up designs and differentiate our products from competitors, the internet offers
lots of potential solutions.
To know which solution is right, having a reliable and trusted source of information
is vital. That’s why we’ve introduced a suite of essential design resources from RS,
all available online, for engineers. Our major new initiatives are Component Chooser,
3D CAD model downloads, DesignSpark and DesignSpark PCB – read more about
these exciting new developments on page 6. This is in addition to the Embedded
Development Platform (EDP) launched in April with access to the new ARM mbed
microcontrollers – read the latest update on page 36.
Furthermore, we have just launched the first fully integrated online quote management
service. This powerful, comprehensive and flexible new tool offers an invaluable service
for engineers and buyers – read more in Newslines on page 5.
Terms and conditions: Terms and
conditions of sale set out in the current
RS Catalogue. This issue is valid from
July 2010 to September 2010.
Published by: RS Components
Limited. Registered office:
Birchington Road, Weldon, Corby,
Northamptonshire NN17 9RS.
Registered No. 1002091. RS
Components Ltd 2010.
RS are trademarks of RS
Components Limited. An
Electrocomponents Company.
ELE_0002_0710
We all have our favourite and trusted sites.
We hope you find our new resources valuable and
that you return to them time-and-time again.
I’m always delighted to receive emails from our
readers and would like to hear more. You can drop
me an email at [email protected] or visit
www.rs-components.com/etech.
Glenn Jarrett
Head of Electronics Marketing
INSIDE eTech
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42
iSay
RS Newsline
New design tools
Product News
ECAD to MCAD
The future is mbed
Review: Parallax Propeller
Arduino: Embedded control
Medical instruments
Design Tips: Elektor
Essentials
Automotive CONNECTORS
EDP update
32-bit technology
Lunch Break
Industry News: Fraunhofer
eTech - ISSUE 3
03
iSAY
RS
NEWSLINES
Simon Whittle, Chairman
OpenET Alliance And Design
Centre Manager, Nujira says:
New Resources for Designers
“envelope
”
Thinking
First phases revealed in new programme to
provide essential online resources to speed
up design process.
outside the
New online bill of materials
quotation service launched
RS website gives customers full quote
management capability
RS has launched the first complete online quotes
management service for customers. Users of the service
are provided with full visibility of their quotation process,
making product identification, pricing and redemption
faster and easier to manage. Customers will be able
to go to their My Account area and upload their bill of
materials (BoM) into the website, with up to 500 lines.
The BoM will be matched against RS part numbers,
manufacturer (including manufacturer part numbers)
and descriptions to return an accurate priced quotation
back for confirmation. Users will then be able to approve
the quote, automatically placing the order online
against specified delivery dates, and if they choose, also
receive enhanced messaging including confirmation
and delivery updates via RS online.
It’s a funny thing how often the solution to a completely
new engineering problem turns out to be an old
idea that hasn’t previously found its niche. Envelope
Tracking is a beautiful theory first described by Bell
Labs in 1937. It’s proved surprisingly resistant to
implementation, but now turns out to be part of the
answer to cellphone networks collapsing under the
data traffic generated by over-eager iPhone users.
Operators are investing in network
capacity but each base station they
add will draw about 3KW. Radio
networks account for about 80% of
an operator’s energy use and carbon
emissions, and about half of this is
dissipated as heat in the transmission
circuit, so operators are pressing for
higher efficiency base stations.
An Envelope Tracking power modulator
adjusts the supply voltage to the
Power Amplifier output transistor
dynamically, in synchronism with
the envelope of the modulated RF
signal passing through the device, so
that the output device remains in its
most efficient operating region. ET
is attractive because it can triple the
efficiency of the PA and is wideband
and modulation scheme agnostic. The
challenge is meeting the accuracy,
bandwidth and noise specifications
at a level of conversion efficiency that
delivers a significant energy saving for
the system as a whole.
04
eTech - ISSUE 3
Nujira finally cracked the problem
in 2002 with High Accuracy Tracking
(HATTM) and momentum behind
Envelope Tracking is now growing.
Sumitomo has released an envelope
tracking radio head, and Texas
Instruments, RFMD and Triquint
have all offered support. At Mobile
World Congress, the OpenET Alliance
published a Terminal Interface
specification on the web, allowing any
device or terminal manufacturer to use
the technology.
There are two morals here. One is
not to confound the difficult with the
impossible, and the other is that there
is huge value in blue sky research that
doesn’t have an obvious application.
One could call it ‘thinking outside the
envelope’ perhaps?
To use Online Quotes for your next bill of materials,
go to rswww.com and select My Account.
FCI automotive connectors
range now available
Range extension makes RS the only high service
level distributor to stock FCI automotive lines
“
Momentum behind
Envelope Tracking is
now growing.
”
Design engineers will have access to the FCI OE-quality connectors,
with no minimum order quantity for prototyping, test programmes,
replacement-parts supply and specialist markets such as industrial
vehicles. The range includes wire-to-wire connectors, flex
interconnects, wire-to-PCB and wire-to-device connectors, power
terminals, signal terminals, squib interconnects, high-reliability
enclosures, pin headers and press-fit pins.
RS is supporting customers with over
100 different product configurations
optimised for use in areas such
as engine compartment, powertrain, body and chassis, cockpit
and multimedia.
The new programme from RS
aims to connect with designers at
each stage of their design journey,
reducing the time from concept
to production by making it
easier to search, select,
design with and buy
components online
from RS.
First releases include
Component Chooser,
the powerful new
parametric search and
compare engine that features
over 260,000 electronic and
electro-mechanical products,
exposing 6.5M searchable
attributes. Users can configure
search parameters to specify and
identify components more quickly
and accurately than ever before.
Also launched are 3D CAD
models available for download
to registered online customers.
Over 20,000 products have
3D models available, and all
major download formats
are supported.
As announced in the
April edition of eTech,
RS has also partnered with
ARM to launch an mbed
module for its Embedded
Development Platform (EDP),
helping to bring virtual designs
to life.
For more on the design
resources programme from RS,
turn to page 6 in this edition.
Extended FPGA Range
RS has added over 100 new FPGA products
from Xilinx, Altera and Lattice.
The range expansion creates a comprehensive FPGA
offer from RS, including mainstream Spartan and Virtex
families from Xilinx, providing engineers with affordable
devices and supporting development kits. From Altera
come the current Cyclone families, offering low-power
and high-performance devices. In addition,
coming soon from Lattice will be the ECP2M
family with SERDES and the XP2 nonvolatile FPGA family - all supported
with development kits and
programming aids.
For the latest FPGA additions,
go to rswww.com/electronics
To see the FCI automotive range, go to rswww.com/fci
eTech - ISSUE 3
05
Online &
On time
Design tools are evolving to increase
the productivity of engineers.
The advent of affordable computing changed
many aspects of modern day life, but nowhere
has it been more apparent than in the fields
of electronics and electro-mechanical design.
The move from drawing board to computer
screen was rapid but the transition from
computer assisted drafting to computer
aided design was perhaps more subtle.
However, with continued improvements in graphics rendering, the development
of more capable and accurate modelling algorithms and the ability to translate
those models in to real-world designs means engineers now, more than
ever before, rely heavily on computer-based design tools to deliver better
designs quickly.
These developments in design tools include more effective ways of sharing
information. The engineering community has always benefited from the
dissemination of information and in today’s connected community that
increasingly revolves around the internet. To allow its customers to better benefit
from these trends RS Components has announced the first four of a series of
initiatives to create an authoritative and convenient online source of trustworthy
information that will support customers in making informed design decisions.
Continued page 08>
06
eTech - ISSUE 3
eTech - ISSUE 3
07
DesignSpark PCB comes with a component
library that can be extended and shared –
through the DesignSpark community – with
other engineers. DesignSpark outputs a
flexible format (CSV) Bill of Materials that can
be automatically configured to include the
RS part number for ease of ordering. It can
also be uploaded into RS’ new online Quote
Management service, a tool that enables
an upload of up to 500 component lines for
immediate price and availability verification
and response.
08
eTech - ISSUE 3
3D CAD
When entering the mechanical design phase,
the availability of electromechanical and
interconnect 3D models can significantly
reduce the product design cycle. Unfortunately
availability of such models in a format
compliant with the engineers’ preferred CAD
suite is limited at best. Visitors to the RS
website will see the results of the work to
remedy this as 3D models for the first 20,000
of its 45,000 electromechanical components
are made available, each compliant with over
20 major CAD suites. The remaining 25,000 are
under development and will be added to the
RS website over the coming 9 months.
In order to achieve this RS has partnered with
Traceparts, a leading 3D content supplier to
give customers access to Traceparts’ expertise
These are the first results of a renewed
emphasis on playing a key role throughout
the design process, but not the last. By
delivering DesignSpark PCB, Component
Chooser and 3D CAD models, and with our
new DesignSpark website, RS is showing
its commitment to providing the design
community with the right tools for the right job,
in the right way.
“
The engineering
community has
always benefited
from the
dissemination
of information
”
Serial
EEPROMs
DesignSpark will also form the distribution
hub for a range of design tools to be launched
by RS. The first is DesignSpark PCB; a fully
featured PCB design tool, available free of
charge to all DesignSpark members without
limitation. Engineers can create schematics
for any sized PCB, with any number of
layers. Fully (auto)routed and design-rule
checked designs can then be exported in a
number of file formats including IDF, DXF
and standard Gerber/manufacturing format.
To download and evaluate DesignSpark PCB
from the DesignSpark website, register as a
DesignSpark member to obtain an activation
code that will unlock the ‘Save’ functions of
DesignSpark PCB.
This online search facility, called Component
Chooser, provides an easy to use interface
that allows users to search RS’ entire stock
of electronic components on the most
extensive range of parameters available in the
industry, quickly returning a shortlist of possible
solutions. The number of attributes held
against each component technology has more
than doubled, and each parameter for every
component has been normalised, so results
are presented in a consistent format. This
enables simple and reliable comparison
of products for price, performance
or compatibility.
Analog
DesignSpark
DesignSpark is a dedicated website for
electronic engineers providing a trusted set
of design resources, reviews and industry
interaction to simplify and speed up the design
process. A major part of DesignSpark is the
independent reviews for development kits and
evaluation platforms, provided by engineers,
for engineers. Members are also able to voice
their views through blogs, creating themes
around the latest technology trends.
At product line level, visitors to the RS website
will see a rotating 3D model of the part. Once
the correct component has been successfully
identified, registered users can simply
download the 3D model in a file format that
suits them. Another advantage of this approach
is that a unique image will exist for all product
variants. In the past families of products were
often represented graphically by a single image
for one particular popular or high level variant
within that product range. This will help remove
any ambiguity when it comes to correct
product identification.
Digital Signal
Controllers
< Continued from page 07
Component Chooser
One of the biggest challenges the engineering
community faces is the time taken to navigate
the wealth of online information. Crucially, one
of the most fundamental decision processes in
any project is component selection and, here,
RS is forging the way with a new, industryleading parametric search engine that will
enable the engineering community to intuitively
search, select and compare electronic
components more efficiently and effectively
saving valuable time.
World’s Lowest Power Microcontrollers
with USB OTG
LOW PIN COUNT USB
STARTER KIT
Extend the battery life in your portable USB application using PIC®
microcontrollers with integrated USB and XLP technology. Get the
world’s lowest power USB microcontrollers with the flexibility to
communicate as an embedded host or device.
• Supports PIC18F14K50 Family
• Includes PICKitTM 2 Programmer
• Tutorials for USB Novices
• Combine eXtreme Low Power with Full-Speed USB device, embedded host,
dual role and On-The-Go
• Download FREE USB stacks and drivers including thumb drive support
- Host, OTG and Device Stacks
- Class Drivers (HID, Mass Storage, CDC Drivers)
- Thumb Drive Support (Mass Storage Driver, SCSI Interface, File Management)
DV164126 RS Stock No 667-7980
Get more online...
Join DesignSpark and
get DesignSpark PCB at
www.designspark.com
Search and select with
Component Chooser at
rswww.com/cc
Get the latest 3D CAD models
available for download at
rswww.com/3D
Microcontrollers
in the delivery of 3D content, one of the most
important elements of which is its ability to
supply a file type native to the majority of the
world’s most popular CAD packages.
Family
Flash Program
Memory (KB)
Pins
USB Type
Sleep Current Sleep with Watchdog Sleep with Real
(nA)
Timer (nA)
Time Clock (nA)
PIC18F14K50
8-16
20
Device
24
450
790
PIC18F46J50
16-64
28-44
Device
13
813
813
PIC24FJ64GB004
32-64
28-44
OTG, Dual Role, Embedded Host, Device
20
220
520
Intelligent Electronics start with Microchip
rswww.com/microchip
www.microchip.com/usb
The Microchip name and logo and the Microchip logo are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. © 2010 Energizer. Energizer and other marks are trademarks owned by
Energizer. All other trademarks mentioned herein are property of their respective companies. © 2010, Microchip Technology Incorporated. All Rights Reserved. ME254Eng/04.10D
PRODUCT
NEWS
Thermoelectric Power
Generation Module
Controlling the temperature of
components in an efficient manner
n A range of semiconductor thermoelectric
devices working on the Peltier effect when
supplied with a suitable electric current,
these modules can either cool or heat. When
subject to an externally applied temperature
gradient these devices will generate a
small amount of electrical power. These
solid-state devices offer long term stability
and have the advantage of not generating
any acoustic noise. The larger devices
can be used for cooling or controlling the
temperature of sub-assemblies. The small
size of the mini module makes it ideally
suited for cooling miniature electronic
components such as infra-red detector
chips, microwave IC’s, fibre-optic lasers
and detectors.
Online search term: GM2*
Molex XRC Sealed Connectors
XRC sealed, plastic-circular connectors meet
the demanding requirements of the nonautomotive transportation market
n Never before has Molex offered such an economical, rugged,
sealed, circular connector. The XRC (Extra Rugged Circular) 14and 31-circuit (18 and 24 shell size), circular connectors are ideal
for heavy-duty applications such as trucks, buses and agricultural
markets. For maximum design flexibility, the XRC plugs and
receptacles are available in standard and reverse gender. The
connectors can be used for in-line or panel-mount applications.
Designed to meet IP67 standards, XRC plugs and receptacles
protect against the ingress of dust, water and other contaminants
to maintain the integrity of the mated pair.
Online search term: Molex XRC
n The QT1106 is a self-contained, patented charge-transfer
capacitive controller capable of detecting near-proximity or touch
on up to seven electrodes and a wheel. It allows electrodes
to project sense fields through any dielectric such as glass or
plastic. These electrodes are laid out as a scroller (e.g. a
wheel or slider) plus seven additional independent
keys. The QT1106 can be assessed using the E1106
evaluation kit. The kit provides a convenient reference
design and allows the user to visualize discrete touch
buttons, dials and sliders using interchangeable
QWheel and QSlide touch panels.
Online search term: Atmel QTouch
48/12Vdc ECO 160 series
Switch mode power SUPPLIES
Switch Mode 35W to 200W High, Open
Frame Power Supplies
n RS has been renowned for providing quality
products, under its own name, for over 70
years. Now we’ve expanded our PSU range to
be of one of the most comprehensive around
for general industrial applications. This family
are all in a “2 *4” footprint, rated at 160Watt
with Power Factor Correction. Running at 90%
efficiency they are approved for medical
applications. Other features include short circuit
protection, circuit overload and over voltage
protection. The input voltage varies from 5V
to 48V with the maximum current from 2.1A to
20A. All the power supplies are guaranteed for
3 years and comply with all the standard safety
approvals.
Online search term: eco-160
eTech - ISSUE 3
Xilinx CoolRunner II
Seoul Semiconductor
ACRICHE 4W Square Module
Light source powered directly from the mains
A leading CPLD family featuring
low power capabilities
n The CoolRunner™-II 1.8V CPLD family leads
the industry with its high performing, low power
capabilities. Enhanced with revolutionary features
such as DataGATE, advance inputs/outputs and
the industry’s smallest form factor packaging,
CoolRunner-II CPLDs deliver the ultimate system
solution for today’s design challenges. The family
delivers advanced system features and low power
operation that enable the integration of discrete
system functions into a single re-programmable
device. They are offered in a wide range of densities,
abundant I/O, and the user has the flexibility to move
from one density to another in the same package.
Online search term: Coolrunner - II
n Acriche is the world’s first semiconductor light source
that operates directly from AC power without an additional
conversion circuitry. This makes it suitable for many
residential and commercial lighting applications where the
main source of available power is AC. A design with Acriche
product minimizes component count and board space. The
operating voltage range
from 100V to 230V and
the lifetime is over 35,000
hours. The modules
are available in warm
white and pure white
with multiple package
options. Applications for
the modules are general
STMicroelectronics 2W LED DRIVER
lighting, architectural
lighting, street lighting,
Offline LED Driver board using VIPer17, STEVAL-ILL017V1
residential lighting (Undercabinet), decoration lighting
n This board demonstrates a 2W non-isolated offline
and sign lighting.
constant-current LED driver based on the VIPer17 offline
Online search term:
converter. The VIPer17 features hysteretic thermal
Acriche 4W
protection, soft-start and safe auto-restart after
the removal of a fault condition. Burst mode
operation and the very low consumption of the
device combine to meet standby energy saving
regulations. Advanced frequency jittering reduces
EMI filter cost. The board provides 500mA constant
current for LED applications providing overtemperature protection, LED open-circuit protection,
and LED short-circuit protection.
Online search term: STEVAL-ILL017V1
RS Embedded
Development platform
Featuring an mbed module for easy
implementation of additional firmware
Cyclone® III FPGA family
A family of low cost, low power Field
Programmable Gate Arrays from Altera
n The Cyclone® III FPGA family offers an unprecedented
combination of low power, high functionality, and low
cost to maximize your competitive edge.. To address your
unique design needs, this FPGA family has up to 200K logic
elements, 8 Mbits of embedded memory, and 396
embedded multipliers, Cyclone III LS devices
are ideal for processing intensive lowpower applications including: Automotive,
consumer, display, industrial, military,
video and image processing and wireless
applications.
Online search term: Altera Cyclone III
10
product
NEWS
Atmel QTouch Controller
n This Command Module for the EDP utilises
an ARM7 LPC2368 device from NXP. The mbed
Module plugs into an mbed Adapter Board, which
fits into the EDP Baseboard allowing access to the
features of the EDP. The mbed Module introduces a
new way to write embedded firmware. Instead of having
a C compiler license installed upon the users machine the
mbed Module makes use of a C Compiler installed on a virtual
host. The software and project are built within the framework of
an HTML page and the resulting binary image file is transferred.
By rebooting the mbed Module the new image is flashed into the
hardware and the mbed Module runs your application code.
Online search term: mbed module
See more online - Over 5,000 new products are added at rswww.com/electronics every month
osram Oslon SSL LED
The new class of light
n One of the world’s smallest LEDs in the 1 W
sector. Small in size, big on performance – that is the
new ultra-white Oslon SSL LED from OSRAM Opto
Semiconductors. Its package measures just 3 x 3 mm
but in terms of luminous efficacy the LED is among
the greats with a typical value of 100 lm/W. The LED
provides light that is ideal for spotlights, desk lights
and ceiling floodlights. At an operating current of 350
mA this light source achieves a typical brightness
of 110 lm in ultra-white (5700 and 6500 K), with a
maximum possible luminous flux of 130 lm.
Online search term: Oslon
eTech - ISSUE 3
11
In just about every industry you care to mention,
a metaphorical brick wall has at some stage existed
between the various design departments. It used
to be that electronic and mechanical designers rarely
met – apart from at weekly update meetings – such
was the lack of interaction between the
two disciplines.
These days, contemporary business models – driven
by rapidly changing customer demands and the
need to drive down costs – dictate that a faster and
more efficient concurrent approach is adopted in
the pre-launch design and evaluation phase of any
engineering programme. To successfully embrace
this concurrent approach regular and pertinent,
real time, coherent communication is vital; and
the passage of this information between two
departments or disciplines must be as efficient
as possible.
Adding the
3rd Dimension to ECAD
In the never-ending mission to get to market faster, design departments are as
crucial as ever. This importance is not just restricted to their role in determining
how a product is manufactured; but also how effectively they interact with other
departments in order to make the early stages of a product’s lifecycle as smooth,
cost effective and as efficient as possible.
12
eTech - ISSUE 3
Although the take up of modern business practices
has been successful in theory at the project
management level, it is often the practical tools at
the disposal of the engineers that let them down.
In the world of design – and CAD especially –
electronic CAD (ECAD) has changed very little in its
core offering over the past few years, staying firmly
rooted in the 2D world. This is in direct contrast to
CAD in the mechanical world (MCAD), where the
move into the 3D realm is now the dominant
industry trend.
It is of course arguable that the extra ‘D’ – taking
2D to 3D – is not a major necessity in the design of
electronics; being primarily a physically flat design
environment with only minor intrusions into the
Z axis. However, with the burgeoning expansion
of mechatronics and electro-mechanical systems
ECAD and MCAD are meeting head on and merging
in what is currently a very loosely defined middle
ground. This merging of information across design
departments has, in fact, always been a possibility,
but it has never been the most effective and efficient
practice in terms of data hand over and translation
from an ECAD package to an MCAD package.
Continued page 14 >
eTech - ISSUE 3
13
UTS Hi seal
IDF import sub-routines, designed especially to handle
this type of data. The traffic is also far from one way. In
many instances it is necessary to transfer MCAD data to
ECAD packages in order to provide physical restraints for
PCB shapes, mounting points or height restrictions for
example. Like their MCAD peers, ECAD packages also
cater for this eventuality with dedicated import filters.
< Continued from page 13
This is all set to change. Not only are many of the leading
ECAD software companies starting to investigate the
introduction of 3D CAD in the electronics market (flex
circuits, thermal airflow effects and chassis design) but
they are also looking to make the transition from ECAD
to MCAD a much less painful experience. Before 3D
becomes truly native in the ECAD world, the next best
thing is an easier way to transfer design data. It used to
be that the file information behind entire PCB assemblies
would be transferred to the MCAD packages, with
huge amounts of unnecessary data going with them,
but intermediary steps have been developed which
are not only faster, but more efficient and require far
less post processing.
“
The next generation of
engineers... are used to seeing
free software
”
This “middle step” often comes in the form of an
Intermediate Data Format, or IDF, which breaks the
ECAD data into “easily digestible” chunks, which the
MCAD package finds far easier to import. By only
swapping the physical data that is required, the amount
of information transferred is cut significantly too, making
the entire handover far quicker. In many cases two files
are generated; for example, one file will contain physical
information about the PCB such as its shape, the location
and orientation of each component, hole locations
and “areas of concern”. The other file will contain the
component information such as its size and shape.
It is not just the ECAD packages doing all the work
though. Most leading MCAD packages will have specific
14
eTech - ISSUE 3
As well as the structures, components and data that are
obviously mechanical or electrical, there is of course the
electromechanical realm and the world of mechatronics,
which don’t really belong in either domain, but play a vital
role interconnecting them. In these instances, the data
flow can be back and forth and must maintain its efficacy
as it migrates between packages; in many cases, CAD
package-specific files are often the favoured route.
The CAD industry and the companies that rely on it to
disseminate data are also looking to the future, especially
to the growing number of users classed as Generation
‘Y’ – the next generation of engineers who are used to
seeing free software variants, such as Google SketchUp.
Although Google SketchUp only represents 1% of
current MCAD seats, the availability of a free SDK and
supporting community have taken it from an architecturaltargeted package into the industrial space; and this is
making it an important platform to address for the future.
Dynamic IP68/IP69K
Waterproof connectors in mated and unmated condition
Protection of electronics inside the equipment/boxes in case
of maintenance, unmated conditions or cable damage
Sealed
unmated
f
oo
-pr ing
n
sio us
rro ic ho
o
C ast
Pl
■ Operational safety - ESD
· plastic shells
■ Rapid and secure locking system
· quick disconnect
■ Suitable for overmoulding
· sealed insulator and contacts
■ Available :
· 4 shell sizes,
· 16 different layouts
· multiple polarization options.
· standard connectors supplied with
preassembled solder and PCB contacts.
■ UV resistant
· suitable for outdoor use
RoHS
Compliant
SOURIAU your Key Success Partner
www.souriau-industrial.com
advert_led_rs_halfpage.qxp
14.05.2010
10:02
Seite 1
RCD series: drivers that shed new light
The RCD series is a step-down constant current designed for high power LEDs use, potted, smallest, high
efficiency and wider input/output voltage range, it also provides two kinds of dimming controls (PWM and
Analogue) to meet a wider variety of customer demands.
The key features of the RCD series at a glance:
Google SketchUp
SketchUp is undoubtedly going to gain some serious
ground in the next few years if its early adoption rates
are anything to go by. The basic free version is also going
to be many people’s first foray into the 3D realm, so it
has an important role to play – a fact certainly not lost on
many of the suppliers and software developers as they
make sure SketchUp forms a major element of their
future business roadmap.
Find the lastest RS 3D CAD models available
for download at rswww.com/electronics
✔ Supplies up to 10 x 2-watt power LEDs
✔ Accurate constant current output
✔ Wide range of output currents
✔ Wide range of output voltages
✔ PCB and wired versions
✔ PWM dimming
✔ Up to 97 percent efficiency
✔ Analog dimming function
for linear output dimming
✔ Short circuit protection
RECOM Part No. RS Stock No.
RCD-24-0.35 RCD-24-0.50 RCD-24-0.50/W RCD-24-0.70 RCD-24-1.00 RCD-24-1.00/W RCD-24-1.20 416-913
472-228
667-1664
472-222
668-9870
668-9882
668-9889
For more parts visit: rswww.com/Recom
The RCD series.
Highly efficient step-down regulator
for constant-current output for
mbed:
the future of
product development
Adopting new technology is an important step in
product development, but it needn’t be a barrier.
The introduction of programmable devices changed the world of electronics
forever; it ushered in a new era of digital dominance and flexibility. Since
then, the role of embedded software has continued to shape the industry such
that today the predominant investment and risk associated with new product
development is in the bits and bytes that define their functionality.
Continued page 18 >
16
eTech - ISSUE 3
eTech - ISSUE 3
17
“
... ‘cloud hosted’ development
environment gives developers instant
access to the ARM architecture...
< Continued from page 17
The concept of embedded software when
compared with hardware can be a little
‘abstract’, as we can’t ‘see’ the instructions
being executed. For some, this level of
abstraction means the hardware has almost
become incidental, at least during the
development phase. It is possible to model
the processor’s instruction set and develop
entire software applications before the
hardware is even available. This represents
a significant productivity boost and for large
OEMs it has become an important part of
their design process. However the cost
of tools for modelling a microprocessor
can be so prohibitive as to divide the
developer community. In the world of 32-bit
microprocessors this division is amplified
to the extent that it encompasses some of
the conventional development tools such as
integrated development environments (IDEs),
static analysis tools or advanced compilers.
For many developers new to microprocessors
this can represent a significant barrier to
entry, something manufacturers are keen
to remove. In an unprecedented move to
increase accessibility to hardware, ARM
teamed with NXP to introduce an environment
for embedded software development that
exists entirely online. This ‘cloud hosted’
development environment gives developers
instant access to the ARM architecture using
sophisticated software development tools that
are maintained on their behalf and require no
downloads, installations or – perhaps most
importantly - maintenance. What’s more, it
empowers a new segment of engineering to
start developing with 32bit microprocessors,
allowing them to develop prototypes rapidly,
without incurring a steep learning curve or
large financial investment. Engineers more
familiar with programming environments
will appreciate how innovative it is to put the
compiler in the ‘cloud’. There’s nothing to
download or configure, all the groundwork
is taken care of leaving the engineer free to
focus on the application code. What’s more,
unlike some development environments, this
cloud compiler is not restricted to a maximum
number of bytes, lines of compiled code or a
date; once you start programming you’re free
to explore the full features of cloud computing
without restriction. Even for more seasoned
developers, this represents a significant
18
eTech - ISSUE 3
”
productivity boost, as they can start developing
code targeting the ARM7 or Cortex M3 cores
without the need to invest in further tools,
such as an IDE or perhaps even an instruction
set simulator.
The environment is called mbed and while
it is accessed entirely online, it is intrinsically
linked to a local hardware platform which uses
an ARM based microprocessor. Initial mbed
boards use NXP devices but others will be
available in the future. Once connected via a
USB cable, the mbed board appears to the
host computer as a USB memory stick which
holds an HTML file. By simply opening the
file engineers are able to access the online
tools needed to develop embedded software
through their browser window.
Access is controlled by the mbed module’s
‘identity’, so the resources that appear on
screen are directly relevant to the mbed
module attached. This makes configuration
of the design environment unnecessary;
the first step towards removing the barriers
to entry for newcomers. The next step is to
demonstrate how accessible the hardware
is by writing, building, downloading and
running the mbed equivalent to the ‘Hello
World’ application normally associated with
software development. For those unfamiliar
with this, it is customary for the first program
developers write using a new language to be
a simple ‘Hello World’ message on a screen.
As the mbed modules aren’t configured with
screens, the equivalent task is to make an
LED on the board flash on and off. By
understanding this simple program,
users will rapidly become familiar with
the process of writing, compiling and
downloading programs to the
mbed platform. And as they
see the results immediately,
it reinforces the link between
hardware and software,
allowing engineers unfamiliar
with embedded software
to overcome the ‘abstraction’
between the two.
The hardware is provided in a modular
format that gives the engineer access to
all of the microprocessor’s resources, such
as timers, I/O, PWM generators and more.
Many engineers not familiar with high level
embedded software development for 32bit
devices will still be familiar with the peripherals
and resources they offer, so those coming to
mbed with experience of microcontrollers and
assembly code should feel comfortable with
the mbed platform and what it can offer. The
real benefits of the mbed environment will
be clear once the engineer starts developing
more complex software. It uses C/C++, or
rather it uses C and makes use of some the
useful features of C++, such as classes. Those
not familiar with C, C++ or object oriented
programming might see this and shiver, but
don’t be put off; mbed makes it really easy to
learn about high level languages (which is what
C is) and how to use them.
For instance, there are tutorials on the mbed
website that will guide the newcomer through
their first program, explaining how the
compiler works, as well as why ‘include’ files
make it really easy to write complete programs
using just a few additional lines. There is
already an active mbed community, too, which
offers advice, encouragement and a growing
repository of embedded software targeting the
mbed platform. As the community grows so
too will the resources it offers.
Surround
yourself with
safety.
The world of embedded electronics is
constantly changing; it enjoys one of the most
active areas of technological investment and
development, as it plays such a vital role across
all industrial sectors. The mbed environment
demonstrates that the way we access
this technology is also changing, making it
easier than ever for more engineers to start
developing with advanced microprocessors.
Digital Multimeters
Digital Oscilloscopes
For the latest ARM mbed
microcontrollers and development
kits, visit rswww.com/electronics
Capacitance Meter
LCR Meters
Multi-Function Calibrator/Meter
Clamp Meters
Not to mention
greater accuracy and
more features.
Performing at your best in hazardous work
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Agilent.
For a free application note
and product information
www.agilent.com/find/GoOrange
© 2010 Agilent Technologies, Inc.
Agilent and our Distributor Network
Right Instrument. Right Expertise. Delivered Right Now.
rswww.com/agilent
DESIGN
REVIEW
DESIGN
REVIEW
Get into
Parallel Processing
with the Parallax Propeller
™
By Dr William Marshall, RS Components
Every now and again something different comes along. Microcontroller chip
development has proceeded down the same paths for many years now: either
the same basic ‘core’ processor being surrounded by more and peripherals or
the processor itself being made more and more powerful.
Cog 0
Cog 1
Cog 2
Cog 3
Cog 4
Cog 5
Cog 6
Cog 7
Pin Direction
Pin Output
I/O Output Reg.
I/O Direction Reg.
Video Generator
Counter A + PPL
Counter B + PPL
I/O Output Reg.
I/O Direction Reg.
Video Generator
Counter A + PPL
Counter B + PPL
I/O Output Reg.
I/O Direction Reg.
Video Generator
Counter A + PPL
Counter B + PPL
I/O Output Reg.
I/O Direction Reg.
Video Generator
Counter A + PPL
Counter B + PPL
I/O Output Reg.
I/O Direction Reg.
Video Generator
Counter A + PPL
Counter B + PPL
I/O Output Reg.
I/O Direction Reg.
Video Generator
Counter A + PPL
Counter B + PPL
I/O Output Reg.
I/O Direction Reg.
Video Generator
Counter A + PPL
Counter B + PPL
I/O Output Reg.
I/O Direction Reg.
Video Generator
Counter A + PPL
Counter B + PPL
32
32
P31
P15
P30
P14
P29
P13
P28
P12
P27
P11
P26
P10
P25
P9
P24
P8
I\O
Pins
P23
P7
P22
P6
P21
P20
P5
P4
512 x 32
RAM
512 x 32
RAM
512 x 32
RAM
512 x 32
RAM
512 x 32
RAM
512 x 32
RAM
512 x 32
RAM
512 x 32
RAM
P19
P3
P18
P2
Processor
Processor
Processor
Processor
Processor
Processor
Processor
Processor
P17
P16
P1
P0
32
32
Pin Inputs
32
System Counter
32
Data Bus
16
Address Bus
P28
P29
P30
P31
VSS
P27
34
35
36
37
38
39
VDO
40
P1
P2
P0
41
42
43
P3
44
VSS
P4
1
33
P26
P5
2
32
P25
P6
3
31
P24
P7
4
30
VDD
P9
10
24
P21
P10
11
23
P20
22
P22
21
P23
25
20
26
9
19
8
P8
18
VDD
17
VSS
16
XI
27
15
28
7
14
29
6
12
5
RESn
12
VSS
BOEn
XO
P19
P18
P17
P16
VSS
VDD
P15
P14
P13
P12
RESET
Reset Delay
(~50 ms)
Brown Out
Detector
BOEn
Bus Sequencer
Cog
0
8192 x 32 RAM
CLKSEL
RESn
3
RC Oscillator
12 MHz / 20 MHz
SOFTRES
5
PLLENA
XI
OSCENA
OSCMODE
2
Crystal Oscillator
DC 0 80 MHz
(4 - 8 MHz with
Clock PLL)
Clock PLL
1x, 2x, 4x, 8x, 16x,
(16x must be
64 - 128 MHz)
Clock
Selector
(MUX)
Hub
Cog Enables
Cog
6
Lock Bits (8)
SOFTRES
PLLENA
OSCENA
OSCMODE
CLKSEL
2
3
Configuration
Register
Cog
1
Cog
7
8192 x 32 ROM
CLOCK
System
Counter
CLOCK
3
XO
P11
Hub
Power Up
Detector
(~10ms)
VDD
System
Counter
Cog
2
RAM, ROM,
Configuration,
Control
Cog
5
Cog
3
Cog
4
Hub & Cog Interaction
Fig. 1
20
eTech - ISSUE 3
I/O
Pins
The common feature is a single processor
supported by specialist, dedicated logic
providing features like Pulse Width Modulation
output and pulse- counting input. The Propeller
from Parallax represents a major change in
design philosophy. This device contains eight
32-bit processors or ‘COGs’ with minimal
support logic and only the most basic I/O
hardware (Fig.1). A first reaction to this layout
might be: ‘Great, I can implement that Neural
network project with each COG running
essentially the same program’.
While pure parallel processing may indeed be
a good use for the Propeller, I don’t believe this
was the main driver behind the design. The
idea is to give the engineer maximum control
over the peripheral system in a particular
application. You may still have a single COG
running the top-level program, farming out
lower-level tasks such as serial I/O to another
COG as and when required. This is the really
fascinating feature of this device: the ability
to reconfigure itself under program control
to suit the requirements at a particular time
and then to shut processes down when no
longer needed, perhaps re-assigning processor
resources to a completely different task. The
processor clock is also under program control
so power consumption can be reduced if high
speed is not needed when implementing slow
I/O such as RS-232.
The Starter Kit Hardware
The kit contains a very small demonstration
board packed with various I/O sockets, some
rather surprising: VGA output to a monitor, TV
output, PS/2 keyboard and mouse sockets. The
video outputs are provided because the chip
contains as part of its central resource ROM,
the look-up table of a character generator. The
only ‘conventional’ I/O port is USB derived from
the on-board FTDI chip. The UART function that
drives this device is of course implemented
entirely in software and runs on one of the
COGs. All communication with the IDE
software on the PC - Propeller Tool – is via the
USB port. There is a serial EEPROM on-board
which communicates with the Propeller via an
I2C bus which, you guessed it, is implemented
in software run by a COG. It provides nonvolatile memory for user programs. These
I/O routines are loaded from system ROM at
Reset to allow programs to be downloaded
from the PC or from the EEPROM, but are
then shut down before the user’s program
begins execution. If your program requires
these I/O resources, then it will have to load
them and assign COG(s) as appropriate. This
may seem awkward at first, but why have
unwanted resources cluttering up memory
space if you don’t need them?
Propeller Tool
The IDE that comes with the starter kit is
called Propeller Tool and provides program
editing, compilation of the high-level language
Spin, and downloading to the demo board.
You have the option of programming in Spin,
assembly language or a combination of both.
Obviously the assembler produces more
efficient, faster operation and there is the
usual trade-off between faster development
and faster operation.
The editor screen is very colourful and the
automatic assignment of different colours
to code blocks aids understanding of the
program structure. There are two options
for downloading and running: compile and
run in COG RAM, and compile and send
to the external EEPROM from where it is
automatically loaded into RAM by the device
bootloader. The former is best for development,
only transferring to non-volatile memory when
the code works.
Using the Demo Board
To illustrate some of the main features of
Propeller programming, a task was devised
involving the speed control of a small DC
motor using PWM. Two pushbuttons provide
Speed Up and Speed Down inputs. The drive
capability of the I/O ports is insufficient for
the motor used so an H-Bridge circuit was
constructed from half of an L293D quad driver
chip. This was mounted on the breadboard
together with two ‘Tact’ switches, pull-up
resistors and decoupling capacitors (see picture
on page 23). Note the use of the D-variant of
this chip which has built-in protection diodes
for driving inductive loads. Only Ports 0 to 7
of the Propeller are available to the user out
of a possible 32, the others being committed
to EEPROM busses, etc. on this demo board.
The Propeller is a +3.3V device although both
+3.3V and +5V regulated supplies are available.
Hence the logic of the L293D works off the
+3.3V supply, while its separate motor supply
pin is connected to +5V. A small but very
useful feature is the Ground or 0V post which
takes the croc clip from a oscilloscope probe.
Programming in Spin
A possible solution for the program to drive the
motor is given in Listing 1 (see page 22). It is
not presented as an optimal solution but does
illustrate some of the key features of Propeller
programming. The aim is to use two COGs;
one driving the PWM output with a mark/
space ratio set by the global variable Ratio, the
second monitoring two push button inputs and
setting the value of Ratio. The PWM frequency
is to be 1kHz.
The CON statements set up two system
constants and fix the clock speed. We
decided on a 20 MHz clock so the internal
PLL multiplier is set to 4 given the 5 MHz
crystal supplied with the board. Next, the VAR
statements set up global variables: Ratio as
mentioned, Period and Stack which assigns
stack space for the second COG.
The first public method, PUB Main performs
the usual initialization tasks including setting an
initial value of Ratio equivalent to 50% PWM.
Each COG has a simple ‘Count/Capture Unit’
made from some registers and a few bits of
logic. There are two identical counters, A and
B each consisting of three registers CTR, FRQ
and PHS. CTR sets the operational mode, PHS
is the accumulator holding the current value
and FRQ is added to PHS when required.
Counter A is used here. First, the CTRA
register is set to select PWM mode and Bit 31
of PHSA connected to output Port 0. FRQA is
set to 1 so that PHSA is incremented by one
for each cycle of System Clock.
Continued page 22 >
eTech - ISSUE 3
21
DESIGN
REVIEW
‘’
‘’
‘’
‘’
DESIGN
REVIEW
**************************************************************
* Simple DC motor speed controller using counters for timing *
*
PWM mark/space ratio from 0 to 100%
*
**************************************************************
‘’Port 0 = PWM output
‘’Port 1 = Speed Up button input
‘’Port 2 = Speed Down button input
CON
_clkmode = xtal1 + PLL4X
_clkfreq = 20_000_000
VAR
word Ratio
word Period
long Stack[9]
‘Ratio = PWM pulse width
‘Period = PWM period
‘Make stack space for COG 1
PUB Main
‘’Initialisation of ports, counters and program start
Ratio := 10000
‘Initial PWM 50%
Period := 20000
‘Set PWM period
ctra[30..26] := %00100
‘Configure Counter A to NCO/PWM mode
ctra[5..0] := %00000
‘Direct Counter APIN to Port 0
frqa := 1
‘Set counter increment to 1
dira[0..2] := %100
‘Set Ports 0 = output, 1 & 2 = input
cognew(Buttons, @Stack)
‘Start COG 1 running Buttons routine
Toggle
‘COG 0 runs PWM generator routine
PUB Toggle | Time
‘’COG 0 produces PWM signal with pulse width set by variable Ratio
Time := cnt
‘Set base time from System Counter
repeat
‘Repeat next 3 lines forever
phsa := -Ratio
‘Load negated Pulse width into PHS
Time += Period
‘Time = Time + Period
waitcnt(Time)
‘Wait for interval set by Time
PUB Buttons | Width
‘’COG 1 monitors two pushbuttons to derive value for Ratio
repeat
‘Repeat next 8 lines forever
Width := Ratio
waitpne(%110, %110, 0)
‘Wait for button press
if ina[1] == 0
‘If Speed UP button pressed
Width := Width + 1 <# Period
‘then increment Width to max Period
else
‘Speed DOWN button pressed
Width := Width - 1 #> 0
‘so decrement Width to min 0
Ratio := Width
waitcnt(6000 + cnt)
‘Wait before checking buttons again
Listing 1. SPIN source code for the PWM demonstration program
22
eTech - ISSUE 3
< Continued from page 21
Now comes the first really interesting
instruction: COGNEW. This is what launches
the second COG. Up to now, COG 0 has been
doing everything, running the boot-loader and
then the first part of our program. COGNEW
tells it to load the public method Buttons into
the next free COG, in this case COG 1, and set
it running. Once it has done that it launches the
Toggle method and runs that from now on. A
feature peculiar to the Propeller is the sharing
of the 32 GPIO port lines by all processors.
Each COG has its own Port Direction register,
each output of which is ‘OR-ed’ with the next
COG’s register (see Fig.1 page 20). A COG
requiring an output port needs to set the
appropriate bit in its Direction register to logic
1. Once set it also enables the corresponding
output from the COG I/O register to drive the
I/O pin. Care must be taken to ensure that two
COGs don’t try and use the same port line for
output, as program operation will not be as
expected! Port input is completely independent
and any COG may read the state of any port
pin at any time. A COG can check its own
output or indeed monitor what other COGs are
doing on port pins they have set as outputs.
The Propeller has no interrupt system so there
are a number of Wait instructions which cause
program execution to pause until some
event takes place. WAITCNT suspends
operation for the specified number of
system clock cycles by checking the
value of a target figure against the
value of the System Counter CNT. In
PUB Toggle PHSA is loaded with the
negative (2’s complement) value of
Ratio. This of course sets Bit 31 or the
‘sign-bit’ of PHSA to logic 1. As this bit
is connected to Port 0, the PWM output
also goes high. PHSA is now automatically
incremented at the System Clock rate by
having FRQA added to it. After Ratio clock
cycles, PHSA reaches zero and Bit 31 changes
to logic 0. That is the end of the PWM pulse.
While all this is happening the COG is sat in the
WAITCNT statement for the duration of Period.
Of course PHSA continues to increment, but
the end of Period will be reached long before
PHSA reaches a value setting Bit 31 high again.
When WAITCNT times out the cycle repeats,
with PHSA being reloaded with –Ratio.
We have thus added some more parallel
operation by having the Counter determine
the pulse width, while independently the
COG program is setting the period. This is
how the PWM waveform on Port 0 is
generated by Toggle.
The WAITPNE instruction in the Buttons
method waits for Port 1 or Port 2 (or both)
to go to a logic 0. In other words it waits for
a button to be pressed. The beauty of these
Wait instructions is that the COG operation
is suspended with its power consumption
reduced by over 85%. You can see that the
COG running Buttons spends most of its time
‘asleep’, only waking when necessary. The
max (<#) and min (#>) statements in Buttons
provide the upper and lower limits for Ratio.
Component List
RS Stock No.
32330 Propeller Starter Kit
405-571
L293DNE Quad half-bridge drive
526-868
Tact push button switch
479-1390
RE280 DC motor
238-9709
Speeding it up
You would normally expect programs run by
an on-board interpreter, in this case SPIN, to
be slower than those in native assembler.
The unique architecture of the Propeller
does to some extent widen the speed gap.
This is because user SPIN code is held in
shared central RAM while each COG runs the
interpreter in its own local memory. The hub
provides access to central resources in a strict
time sequence and a particular COG may be
held up waiting its turn. Machine code from
the assembler is stored and run in the COG
local memory resulting in a considerable
increase in throughput.
Essential reading
Programming and Customizing the
Multicore Propeller Microcontroller
Shane Avery et al ISBN 978-0-07-166450-9
McGraw Hill
Get more online...
A fuller version of this review
along with SPIN source code
files is available at
rs-components.com/etech
eTech - ISSUE 3
23
Arduino
Embedded control as
Easy as...
For designers and students new to
microcontrollers, Arduino represents
one of the most accessible routes
to becoming part of a new era in
embedded control. The Arduino
board is so straightforward and easy
to program that it is accessible to
engineers with no prior experience,
while at the same time offering
enough performance and capability
to address ambitious tasks.
With its low cost of entry, flexibly modularised
approach and vibrant developer community
for support, Arduino is one of the most
straightforward ways to add intelligence to your
design. Arduino allows prototypes to be built
based on multi-pin devices such as the 100pin TQFP ATmega 1280 without resorting to
complex soldering and handling techniques.
The Arduino project was initially developed to
enable university students to create complex
applications running on standardised hardware
platforms. This has largely become possible
through the use of a special programming
language based on C/C++, running in an
environment developed specifically for Arduino
boards featuring Atmel’s 8bit MCUs. It is this
combination of hardware and software that is
now enabling all engineers to explore the world
of embedded control, and RS has recently
become a worldwide supplier of Arduino boards,
making this exciting platform accessible to the
entire engineering community.
“
With its low cost
of entry, flexibly
modularised
approach and
vibrant developer
community for
support...
enable engineers to quickly create complete
systems with almost limitless possibilities.
As an open source project, Arduino has an active
developer’s community, meaning help is never
far away. The Arduino site features blogs from
the team, as well as links to developer forums,
where the topics range from powering up your
first board to designing complete systems.
The accessible nature of software development
for Arduino is unlike traditional embedded
platforms; the IDE provides the key building
blocks to software development and uses a
subset of the C/C++ language syntax, meaning
users only need a very basic understanding
of software development to create real-world
applications. Essentially, Arduino applications are
endless loops, defined using simple constructs
using keywords such as If…Then…Else. The
digital and analogue I/O are referenced directly
using keywords and pin designations, allowing
simple control functions to be created quickly,
while allowing more complex algorithms to be
generated intuitively.
The vibrant community also provides access
to a wealth of existing software, donated
by active developers. It is this willingness to
comply with the spirit of open source that
really underpins the unrivalled growth being
experienced by Arduino. For any engineer new
to microcontrollers, the Arduino project offers
everyone – irrespective of experience
– a chance to expand their horizons.
”
Arduino is essentially a concept; an open
source standard defining a hardware platform
which offers a number of digital and analogue
inputs and outputs (I/O). The behaviour of
the processing board’s I/O is defined by the
program, which in turn is created using the
Arduino integrated development environment
(IDE); a freely available download from the
project’s website (www.arduino.cc).
Arduino’s modular approach extends beyond
the processor, to include add-on boards that
provide specific functions. Known as Shields,
these boards can offer access to wireless
connectivity, such as the XBee ZigBee shield
from Digi International (part number 696-1670),
or the Ethernet shield (part number 696-1661).
Together, the processing boards and Shields
24
eTech - ISSUE 3
RS Components is the exclusive official
global catalogue distributor for Arduino,
stocking the Duemilanove MCU board
based on the Atmega328, ZigBee and
Ethernet Shield boards. Plus workshop
kits containing all the components
required to begin prototyping. See our
range at rswww.com/electronics
eTech - ISSUE 3
25
The front (and back) panel of a medical instrument presents special
challenges to the electronics design engineer. In addition to being clear
and easy-to-use, the equipment must comply with very specific standards
such as the Medical Devices Directive, quality management standards like
ISO13485, and must often be risk-assessed to evaluate the potential for and
the consequences of incorrect connection and use.
In particular, with a vast amount of
instrumentation, information systems,
patient care and critical care equipment in
use in hospitals alongside the inevitable
personal and professional wireless
communications systems, careful attention
to electromagnetic compatibility and RF
immunity is essential
In the constant drive to minimise hospital
infections, front panels will usually need
to be thoroughly and regularly cleaned
and sterilised, especially where patients
have physical contact with the system.
Waterproof switches, keypads and
coverings are essential for front panels
and, whilst IP65 protection against dust and
moisture ingress is adequate to provide
wipe-clean capability, moving up to IP67
allows equipment to be fully immersed and
sterilised.
Prescribing
the right connections
for medical instruments
26
eTech - ISSUE 3
As an example, the whole ITW Switches
range is IP67 rated. Its portfolio of more
than 1500 switches offers designers a
vast array of options, for instance in the
Flex-Tech 57M family of miniature panel
sealed metal pushbutton switches. These
miniature, rugged vandal-resistant switches
have zinc alloy housings and velour chromo
plating, and are available as maintained
or momentary action, in illuminated and
non-illuminated versions.
Reducing the risk of infection
Increasingly, however, prevention of MRSA
and other lethal hospital-borne infections
requires more active defence. APEM, for
example, offers antibacterial coatings
on its membrane overlay, switch and
keypad products, in addition to wipe-clean
IP65/67 sealed switches and waterproof
membranes. Tactile switches have been
developed to meet the very specific
demands of medical devices. A particular
requirement is that usually the operator
is wearing disposable gloves, calling
for a strong tactile feel and audible click.
The reverse is true for equipment used in
audiology, where even a quiet click would
be distracting.
Rear panel solutions
The rear panel normally provides power to
the device alongside any data connections.
Good rear panel design entails reducing
risk of misconnection through clear
labelling and simplicity of use, and keeping
the size and number of connections to a
minimum to improve device portability
and miniaturisation. Connectors with
a wide range of mechanical or colour
coding possibilities are popular to guide
end-users to connect the right cable to the
right socket safely, easily and quickly, and
if necessary prevent potentially dangerous
misconnections. Power inlet modules for
medical equipment need to be double fused
for protection and should offer good mains
filtering to ensure a clean power supply
“
...prevention
of MRSA and
other lethal
hospital-borne
infections requires
more active
defence.
”
with low EM emissions. In addition, there
is a requirement on medical equipment to
keep current leakage as low as possible,
embodied in the IEC 950 standard. Schaffner
FN92XXB and FN28XB series medical IEC
Inlet plugs, for example, have an integral
mains filter that eliminates mains borne
interference beyond the capability of
capacitors alone. Earth leakage current
specifications of 0.002mA/phase ensure
conformity with IEC 950.
Internal and external power supplies
such as those offered by Emerson under
the Astec and Artesyn brand names are
well-suited to OEM medical designs. Those
with medical approvals, namely EN606011, can be designed into patient monitoring
systems and other portable equipment for
use in medical wards and surgical
operating theatres. To meet this standard
the level of leakage current for ac/dc power
supplies is 500 micro amps max at 230V,
with a further requirement for power
supplies and dc/dc converters to have
higher isolation voltages.
Simple, reliable, connectors
When it comes to data connections on
the rear panel, the first prerequisite for
connectors and cable assemblies is
reliability. They need to be engineered with
high quality materials, fully adapted to
medical environments, tested to be shielded
against electromagnetic interference and –
as with front-panel components – must be
able to withstand a range of cleaning and
sterilisation processes.
A prime example is ODU’s MEDI-SNAP®
miniature cylindrical connectors, which
ensure higher safety through blind
mating capability and a push-pull-locking
mechanism. The medical connector
range comes with plastic housing made
from either polysulphone (PSU) or
polyetherimide (PEI) thermoplastics.
These offer superior performance to
standard polycarbonate materials: PSU
can be subjected to repeated cleaning
and sterilisation, whilst PEI is additionally
resistant to autoclaving and steam
sterilisation processes.
From the power inlet to the front
panel, innovative and dependable
electromechanical components like
these are helping designers to meet
the very special challenges of medical
instrumentation and equipment.
Learn more about the growing
range of products supplied by RS that
are suitable for medical applications
at rswww.com/electronics
eTech - ISSUE 3
27
DESIGN
TIPS
IN ASSOCIATION WITH
D26
people find it more difficult
to reverse a car than drive
forwards. In any case, it is much trickier to
estimate how much space there is between an
object and the rear bumper, and looking behind
you can result in an unpleasant feeling in your
neck. A solution to this problem is the reversing
aid, which indicates how much further you can
drive backwards without hitting anything. The
circuit presented here should be mounted in a
fixed position, for example on the back wall of
a garage. With the help of a clearly positioned
visual display you can tell if you can reverse
further without crashing into the wall.
Principles
For the measurement of the distance we use
a special sensor made by Sharp, the GP2D120.
The sensor measures the distance with the
help of an IR LED that has a wavelength of
about 850 nm. The output voltage of the sensor
becomes less as the distance increases.
The visual display of this ‘radar’ consists of a
number of LEDs that start to flash when an
object comes within range of the sensor. The
closer the object comes to the sensor, the
faster the LEDs will flash. A VCO (Voltage
28
eTech - ISSUE 3
Controlled Oscillator) has
been used to implement
this. The LEDs will turn on
permanently when a minimum
distance has been reached.
Circuit diagram
As we mentioned earlier, the GP2D120
(MOD1 - in figure 1) measures the distance
and reduces its output voltage as the distance
to the object (the car) becomes greater. The
relationship isn’t inversely proportional and
neither is it linear, since the angle of reflection
changes less as the distance increases. In
4
2
C6
10u
63V
C5
IC1
100n
11
R18
D5
D10
D15
D20
D6
D11
D16
D21
D7
D12
D17
D22
D8
D13
D18
D23
D9
D14
D19
D24
R19
R20
R21
R22
OUTPUT
CIRCUIT
R10
R9
The output voltage of the sensor is monitored
by opamp IC1D, which is configured as a
comparator. Its function is to make sure
that the LEDs start to flash with a minimum
frequency when an object comes within range.
P2 is used to adjust the voltage across R11
between 0.1 V and 0.32 V. At the lowest setting
of P2 the sensor appeared to have a range of
about 1 m. That was surprisingly more than
IC1A
1
6
R2
100k
R6
T1
R7
22k
7
IC1B
D3
BAT85
R12
1k
BC550C
R14
IC1D
14
D4
D2
BAT85
C4
R13
470u 25V
+5V
330R
330R
BD139
R17
BAT85
10
1M
13
2k7
R11
+12V
T2
9
R15
IC1C
8
100k
12
K1
R16
4k7
P2
100k
R8 has been chosen such
that the hysteresis is
about 0.5 V. When the
VCO is operating the
hysteresis is between
3.4 V and 3.9 V. The
maximum input voltage of
the VCO is then about 3 V.
With the right settings – in our
prototype we set the voltage on
the wiper of P1 (pin 3 of IC1A) to
1.45 V – this covers the complete sensor
output range. The VCO has been designed in
such a way that the pulse width varies as well
as the frequency. At higher frequencies the
larger current through R3 will cause a larger
current to flow through R4, which means
it will take a bit longer before C3 becomes
sufficiently discharged to make the output of
IC1B switch state again.
2
K2
5
4k7
+5V
R8
470k
R3
100k
39k
LED
GP2D120 2
R1
100k
1
39k
LED
DRIVE CIRCUIT
4u7
63V
220k
VOLTAGE
REGULATOR
OSCILLATOR
CIRCUIT
The operation of the VCO is quite
straightforward. C3 is charged via R3.
(We’re assuming that T1 is turned on.)
When the voltage at the inverting input of
IC1B becomes less than the voltage
at the non-inverting input, the
output becomes high and C3
is discharged via D1 and R4.
The threshold set by R5
and R6 determine the
operating range.
22k
3
R5
C3
100n
3
SIGNAL
PROCESSING
CIRCUIT
0.5 V while an object is held at the required
minimum distance from the sensor. The VCO
is then turned off by T1 when the minimum
distance is reached.
R4
68k
P1
100k
C2
100k
BAT85
330R
+5V
D1
PSD
order to properly drive the following VCO
built around IC1B, the signal is first inverted
using IC1A. Preset P1 has been added to
shift the output voltage of IC1A such that it
comes completely within the operating range
of the VCO. The VCO is turned on when T1 is
made to conduct. This is easily implemented
by connecting the base resistor of T1 to the
output of IC1A. To make the LEDs light up
continuously the output voltage of IC1A
has to be adjusted with P1 to be just under
D25
0
MOD1
Most
+5V
3
+5V
100u
25V
It’s not always easy to reverse a car. There are
some good reasons why modern cars are
often fitted with sensors that indicate
when the rear bumper comes
dangerously close to an
object behind the car.
The circuit described here
is the perfect solution to
make parking easier in
fixed locations, such as
in a garage.
C7
IC2
78L05
220u
25V
C1
By Ton Giesberts (Elektor Labs)
based on an idea by Ludovic Meziere (France)
3V6
1W3
12V
IC1 = MCP6004-I/P
1
1k5
Outmanoeuvred
Perfect parking with a reversing aid
+12V
330R
DESIGN
TIPS
090184 - 11
Figure 1. In the circuit diagram we can see some classic applications of opamps:
An inverter and a comparator.
we expected because the data sheet made
us believe that the maximum range was only
30 cm (1 foot). When the voltage output of the
sensor becomes too low the output of IC1D
becomes high and D2 then prevents C3 from
charging up. The output of IC1B will then stay
low. Once the car has been parked, the LEDs
stay on for about 5 minutes before they’re
turned off by IC1C.
IC1C is used to check if the LEDs are flashing.
When the output of IC1B is low, C4 will be
charged up quickly and the output of IC1C
stays high, blocking D4. The LEDs will now be
off in all circumstances. If the output of IC1B
stays high then C4 will slowly discharge via
R13. Finally, after about 5 minutes, the output
of IC1C becomes low and the base current
of T2 is then diverted via Schottky diode D4.
The LEDs will now stay off until the car moves
away again, when the LEDs start flashing
until the car moves out of range.
At the maximum distance the period of the
flashing LEDs is about 240 ms, with a pulse
width of 50 ms (D = 21%). At the minimum
distance the period is 160 ms, with a pulse
width of 95 ms (D = 59%). The change in
frequency from 4 Hz to 6 Hz may not appear
to be much, but the change in the duty cycle
makes it much more noticeable.
Power supply and PCB
The sensor and the circuit built around the
opamps are powered by a 78L05. A zener
diode has been added to the input of the
regulator to keep its dissipation to a minimum.
Otherwise there would be 7 V across the small
regulator, for no good reason. The LEDs are
powered directly from the mains adapter. With
a mains adapter of 12 V you can connect five
red LEDs in series without any problems. The
current consumption in stand-by (no reflection)
is 39 mA. With all the LEDS turned on 76 mA
is drawn.
For this circuit a small single sided PCB has
been designed, which consists of two parts.
The PCB artwork can be downloaded from
the eTech website. The LEDs have been kept
separate so that they can be mounted in a
clearly visible position.
The sensor and the rest of the circuit can then
be mounted in the most suitable location.
Headers have been used for the connection
between the two boards. On the LED side
a right-angled version is most suitable. With
the appropriate sockets you can make an
easily maintainable connection between the
boards. The sensor made by Sharp can also
be connected via a pin-header. The sensor
itself has to be connected using a special 3-pin
socket with a lead pitch of 2 mm, made by JST
(Japan Solderless Terminals).
Continued page 30 >
eTech - ISSUE 3
29
DESIGN
TIPS
Component List
Figure 2. The layout of the relatively small boards makes them
appear fairly crowded. However, due to the use of through-hole
components the soldering shouldn’t cause any difficulties.
Resistors
R1,R2,R3,R14,R15 = 100kΩ R4,R7 = 22kΩ R5 = 68kΩ
R6 = 220kΩ
R8 = 470kΩ R9,R10 = 39kΩ
R11 = 2.7kΩ R12 = 1kΩ
R13 = 1MΩ
R16,R17 = 4.7kΩ
R18 = 1.5kΩ R19 - R22 = 330Ω P1,P2 = 100kΩ preset (Piher) RS Stock No.
151-303
151-167
157-531
157-480
151-331
151-325
151-072
157-446
151-123
151-000
151-094
151-375
473-590
Capacitors
C1 = 100µF 25V, radial, lead pitch 2.5mm (0.1”), diam. 8mm max.
C2 = 100nF MKT, lead pitch 5mm (0.2”) or 7.5mm (0.3”) C3 = 4.7µF 63V, radial, lead pitch 2.5mm (0.1”), diam. 6.3mm max.
C4 = 470µF 25V, radial, lead pitch 5mm (0.2”), diam. 10mm max. C5 = 100nF ceramic, lead pitch 5mm (0.2”) C6 = 10µF 63V, radial, lead pitch 2.5mm (0.1”), diam. 6.3mm max. C7 = 220µF 25V, radial, lead pitch 2.5mm (0.1”), diam. 8 mm max. Opamp choice
For the quad opamp we’ve selected an
inexpensive rail-to-rail version made by
Microchip, the MCP6004-I/P, which is perfect
for this application. The opamp specifications
that have to be considered for this circuit are
not the bandwidth, slew-rate or output current
for a change, but the maximum differential
input voltage. We’re using two opamps as
comparators, which means that the voltage
difference between the two inputs could
be several volts. The opamp used here can
cope with a voltage difference that is equal
to the supply voltage. This supply voltage
can be between 1.8 V and 5.5 V (7 V is
the absolute maximum).
30
eTech - ISSUE 3
Semiconductors
D1–D4 = BAT85
D5–D24 = LED, 5mm, red, low current D25 = LED, green, 5mm, low current D26 = zener diode 3.6V, 1.3W T1 = BC550C T2 = BD139
IC1 = MCP6004-I/P IC2 = 78L05 RS Stock No.
Miscellaneous
K1,MOD1 = 3-pin SIL pinheader K2 = 3-pin right angled SIL pinheader MOD1 (not on PCB) = GP2D120
2 pcs PCB solder pin, diam. 1.3mm
3 pcs BPH-002T-P0.5S, JST BPH-002T-P0.5S PHR-3, JST PHR-3 Socket for 3-pin SIL header RS Stock No.
300-978
646-6670
826-436
812-358
545-2254
314-1823
403-181
398-552
681-3269
681-2521
315-400
434-138
353-1276
353-1311
681-3269
RS Stock No.
684-1942
463-1765
520-1040
684-1958
652-9995
440-6547
193-6815
In many rail-to-rail opamps there are
protective diodes connected in
anti-parallel between the
inputs, which means the
maximum differential
input voltage may only
be 1 V. In theory our circuit
could also use these opamps.
For this reason R9 has been added to the
inverting input of IC1D. As an example, we
tried using a TS924IN. What goes wrong in this
case is that the two inputs of the comparators
affect each other. The time constant of C4
and R13 turns out to be lower because of the
addition of R14 and R15.
Get more online...
Download the PCB artwork
from Design Tips at
www.rs-components.com/eTech
Essentials
TEST LEADS SET
Practical lead set with a wide range of
accessories for taking measurements in
most situations.
CRYDOM SSRs
Solid state relays are the future for reliable
electronic and electrical load switching.
n They contain no moving parts, offer high
resistance to vibration and require lower
currents to operate making them ideal for
use in portable and industrial equipment.
The Crydom range of SSRs includes both
PCB & DIN rail mount versions from 100mA
to 125A with both AC & DC control options.
Online search term: Crydom SSR
Essentials
MULTI-FUNCTION GRAPHICAL METER
An analogue input meter with a programmable
multi-function 320x240 pixel graphcis display
n Supplied complete with Windows based configuration software
the SGD 24-M can be programmed via USB for input scaling and
6 types of virtual meter including analogue meters, VU type bargraphs, or 3½ digit. Powered from 4-30Vdc with a supply current
less than 100mA and supports input voltages from 0-40Vdc.
Online search term: Lascar SGD
n Includes: 2 x 1.2m silicone multimeter
leads with shrouded 4mm terminations one
end straight, one end right angled, (red
and black); 2 x crocodile clips (red and
black); 2 x long reach multimeter probes
with removable 4mm tip exposure adaptors
(red and black); 2 x spring loaded ’grabber’
multimeter probes (red and black).
Complies with IEC1010-1 cat III 600V
safety standard.
Online search term: 262-7742
VISITOR’S / LAB COVERSPECS
Can be worn on its own or over prescription spectacles.
n Ideal for lab or manufacturing areas, the coverspecs are ultralightweight, with a single piece polycarbonate lens moulding. With
a tough construction, they provide excellent all-round visibility.
Meets EN166-1F, with a Class 1 optical lens.
Online search term: 764-142
ECO WIRE
A range of hook-up wire which
uses an environmentally-friendly
alternative to PVC sheath.
n EcoWire uses a modified polyphenylene ether
(mPPE) thermoplastic and contains no heavy metal
pigments, allowing it to help manufacturers meet
Waste Electrical and Electronic Equipment (WEEE)
requirements. Available with a variety of sheath colours
from 28AWG (0.07mm²) to 10AWG (5.37mm²).
Online search term: Eco wire
Antistatic field service kit
LINDSTROM CUTTERS & PLIERS
Ideal for field based personnel that need a
temporary anti-static area to work on
A wide range of high precision tools designed
specifically for use within the electronics industry.
n Available in a lightweight and heavy duty version these kits
include a black wide jaw croc clip, stacking snap
banana, 10 mm male snap riveted to material,
adjustable wrist strap and a ground cord which is
supplied in a plastic service wallet with zipper.
Online search term: 681-1235 & 681-1231
n In addition to cutters and pliers, we also supply
tweezers and screwdrivers from Lindstrom. All
products are manufactured to the highest
standards guaranteeing an accurate and
even action for the life of the tool.
Online search term: Lindstrom
DIGITAL PROGRAMMABLE SOLDERING IRON
Cost effective, entry level soldering station for the intermittent / low
volume user. The hand piece and tips are designed to enable rapid
heat recovery required for Lead Free soldering.
FLUKE 233 MULTIMETER
Be in two places at once with the
new Fluke remote display multimeter.
n The removable display solves the problem of holding both
the meter and the test leads, so taking measurements in
hard-to-reach places is easy. The removable display gives the
user flexibility in situations where display viewing is difficult or
impossible, or in areas where the operator cannot easily be
close to the active measurement point, for example in clean
rooms or temperature test chambers. Wireless technology
allows the display to be carried up to ten metres away from
the point of measurement.
Online search term: Fluke 233
32
eTech - ISSUE 3
TECHSPRAY RENEW™ HIGH
PERFORMANCE
ECO-CLEANING™ FOR SMT
A range of eco-cleaners that are non-ozone
depleting, have very low VOCs (Volatile Organic
Compounds) and no Global Warming Potential
n Digital display with 3 programmable set point temperatures, preprogrammed to: 150, 300, 400°C. Operating temperature range:
150 – 450°C. Supplied with 24V / 48W soldering iron
and 230V power supply, with grounding stud/
socket for critical applications and
ESD work.
Online search term:
665-4789
n SMT ECO-STENCIL™ effectively removes all types
of solder paste and uncured adhesive from
screens, misprinted boards and equipment. It
is a safe replacement for IPA cleaners. SMT
ECO-OVEN™ cleans reflow ovens, wave soldering
systems by removing all types of flux residues.
It is fast acting and more effective than IPA for
baked on flux residues.
Online search term: TECHSPRAY
eTech - ISSUE 3
33
Automotive
“
Although many suitable
solutions are available, they
are commonly targeted at
manufacturers ordering
in high volumes.
”
connector solutions
Vehicle markets worldwide are changing quickly, as factors such as electric
vehicles and rising car ownership in fast-growing economies empower new
brands to challenge established players. Innovations like vehicle buses, LED
lighting and hybrid or all-electric powertrains are especially demanding on
interconnect and switch components.
From specialist government and commercial
vehicles, to motorsport and custom cars, the
automotive industry demands top reliability,
top performance and top cost-effectiveness.
Although many suitable solutions are available,
they are commonly targeted at manufacturers
ordering in high volumes. Where does this
leave the specialist vehicle manufacturer, or
those developing prototype or test designs?
RS is expanding its range of switch and
interconnect solutions through partnerships
with top manufacturers.
components, whilst at the same time handling
a larger number of I/O and higher currents.
This can only be achieved with smaller pitch:
automotive connectors have to deal with
wires less than 0.05mm², yet still operate
at temperatures up to 125°C. Features like
secondary locks, straight-angle “scoop-proof”
mating and low insertion forces are mandated
by standards bodies like USCAR 2 to ensure
that automotive interconnects are assembled
correctly and will therefore perform within
specifications for the whole design life.
Automotive connectors
There is a huge amount of interconnection in
today’s vehicles, whether signals are routed
by conventional wiring looms or automotive
buses such as CANbus, FlexRay or LINbus,
for example. Increasingly, the trend is to use
low-voltage differential signalling (LVDS) instead
of conventional serial or parallel data, with its
advantages of high speed and excellent
EM shielding.
High brightness, low power
The latest automotive designs are putting
still-greater demands on interconnection.
Take, for example, the increasing trend for
LED lighting as daytime running lights for cars.
High-power LEDs have significantly different
requirements from conventional incandescent
lamps: in particular, there is a need to keep
junction temperatures as low as possible
in order to maximise light output and unit
life. Manufacturers like JAE are developing
connectors for main driver modules, cable
assemblies with built-in heat-sinks and
wiring harness connectors to meet these
emerging requirements.
The durable, two-conductor JAE MX38 is able
to withstand tight bend radii and more than
82,000 flex cycles and is ideal for distribution
of high-speed data at LVDS levels, for example
carrying serial data from externally-mounted
cameras in advanced parking and vehicle
guidance systems. LVDS interconnects will
also distribute DVD and TV video and audio
to seat-mounted LCDs, as part of Rear Seat
Entertainment (RSE) systems.
As with other automotive interconnects, the
overall aim is to reduce the size and weight of
34
eTech - ISSUE 3
Another technology that pushes
interconnection to extremes is that of hybrid
and electric cars. Even the charging connectors
require extreme power capacity, reliability and
safety. Connectors developed by ODU for the
new MINI E have two power contacts rated
at 60A, 240V AC, three signal contacts rated
at 1A 42V, nominal current, and a safety-
protected earth offering 60A short-circuit
current capability. The connectors are protected
to IP 66 when mated and operate in ambient
temperatures up to 80°C.
Demands like this are already filtering from the
volume market to systems for lower-volume
applications, such as emergency vehicles,
construction equipment, prototypes and racing
cars, as well as after-market products.
That is why RS is expanding its portfolio rapidly.
For example an exclusive agreement with
FCI Connectors has just been announced to
introduce FCI’s family of automotive products
through high service level distribution for
the first time. OE-quality connectors are
produced by FCI’s Motorized Vehicles Division,
and include wire-to-wire connectors, flex
interconnects, wire-to-PCB and wire-to-device
connectors, power terminals, signal terminals,
squib interconnects, high-reliability enclosures,
pin headers and press-fit pins. Such
agreements give customers rapid access to
specialist automotive interconnect and switch
solutions, with no minimum order quantity for
prototyping, test programmes, replacementparts supply and specialist markets such as
industrial vehicles.
See the latest additions to our
range of automotive components
at rswww.com/electronics
eTech - ISSUE 3
35
EDP
UPDATE
EDP supports
ARM mbed format
The Embedded Development Platform from
RS now offers easier access to ARM processors
The mbed development environment launched by ARM recently
(see the mbed article in this issue for further details) provides
instant access to a very powerful suite of software tools, hosted in
the ‘cloud’ to support a hardware platform for rapid prototyping
and proof-of-concept. Now, RS has added support for the mbed
format to its Embedded Development Platform (EDP), which
will bring even more benefits to developers who are new to the
concept of 32bit processors.
EDP is the perfect complement to mbed, as it too offers a fast and
flexible way of configuring hardware functions using modules.
With the introduction of a special adapter, engineers can now
plug their mbed module into the EDP baseboard and operate
it alongside up to three additional modules, chosen from the
growing number of Application Modules offered for the EDP. This
instantly extends the capabilities of mbed processing modules to
include peripheral functions without the need to build unwieldy
breadboards or develop a bespoke hardware platform.
Our online quote tool is so quick it will
give you a slice of your day back.
The reusability inherent within EDP, coupled with the
open and unrestricted access to mbed’s software
development environment, create a powerful
prototyping platform. Creating a proof-of-concept
has never been easier or more accessible;
mbed is designed to provide engineers
with an easy and intuitive route to 32bit
processing, so no experience is required.
The software development tools are only a
click away, along with a growing repository of
code, examples and advice.
RS is dedicated to providing engineers with the resources
they need to move from concept to prototype as quickly and
efficiently as possible. Bringing together EDP and mbed represents
a significant milestone along the road to simpler development,
giving engineers of all abilities the tools they need to create
prototypes using the latest technologies. The strengths of EDP
include the ability to assimilate other innovative solutions such as
mbed, which means its worth as a reusable, extendable platform
is matched only by its value.
Get more online...
Stay up-to-date with the latest additions to
the RS EDP portfolio at rswww.com/edp
36
eTech - ISSUE 3
Online Quotes
rswww.com/tips
Roadmap to
performance
If you only listen to the manufacturers, all 32-bit processors
offer class-leading performance, so how do you really
choose the right solution for you?
Ease of
development
The number of viable application areas for
microcontrollers (MCUs) is growing and
inherent in that growth is a need for higher
performance. In general, the vast number of
8- and 16-bit MCUs available may cover the
needs of all traditional applications, but the
trend towards ‘smarter living’ is driving demand
for smarter MCUs; devices that can provide
all the usual control functions but with
something extra. Typically that something
extra is connectivity.
The term ‘connectivity’ covers both wired
and wireless communications, but while
established markets have in the past
implemented relatively simple serial protocols
such as RS232/422, today’s applications
require more robust solutions which are
able to support higher bandwidths over
networked topologies. This may include wired
technologies such as USB, Ethernet or CAN,
or wireless networking solutions including
802.11, Bluetooth or ZigBee®. These modern
communication protocols are essentially driven
by standards which are not trivial, requiring a
significant amount of processing power. Many
8- and 16-bit MCUs are able to meet the need
for relatively complex communications, but as
applications become more sophisticated the
need for processing power will increase; realtime operating systems and time-critical
protocols will demand faster, more capable
processor cores and this represents one ofthe
key reasons why the industry is transitioning
to 32-bit based devices. Most MCU vendors
are now actively developing 32-bit solutions but
few are taking the same measured approach as
Microchip. While Microchip’s very successful
8- and 16-bit MCU families use a proprietary
core, Microchip has chosen to standardise its
32-bit families on 3rd Party IP from MIPS. This
benefits Microchip customers by bringing an
entire eco-system of software development
tools to the PIC® MCU platform. Furthermore,
by adopting licensable IP, Microchip is able
to deliver leading-edge performance without
compromising on features.
The 32-bit technology chosen by Microchip
for the PIC32 families is the MIPS M4K
core; it uses a Harvard architecture (separate
data and program buses) and independent
benchmarks show the PIC32 delivers more
performance than competing 32-bit MCUs.
For example, at 80MHz the PIC32 delivers 120
Dhrystone MIPS (1.5DMIPS/MHz) compared
to 1.25DMIPs of the nearest competitor. These
independent benchmarks show the PIC32
completes tasks over 30% more efficiently
than other cores and along with the Harvard
architecture, the core features a single-cycle
hardware MAC, which enables it to complete
many common processing tasks much quicker;
typically the PIC32 would complete an FFT in
28% less time than a comparable 32-bit device.
Seamless
transition
Compatibility
A key focus for Microchip is the compatibility
it offers between its families of PIC® MCU
devices. Through the use of MPLAB®
(Microchip’s Integrated Development
Environment) this extends to the PIC32, as it
offers pin- and peripheral-compatibility with the
16-bit PIC® MCU families, which means code
developed for a 16-bit device will be compatible
with the PIC32 family, providing a true
performance roadmap. This is unrivalled in the
industry, even among vendors standardising
on a common 3rd Party core technology;
predominantly the peripherals, memory
management, interrupts and pin configurations
will be significantly different, both between
vendors and a single vendor’s range of MCUs –
even those using the same core architecture.
In addition, the extensive suite of software
development tools offered by Microchip
remains compatible across all PIC® families,
allowing its extensive software libraries to be
used on all devices, including the PIC32. The
significance of this compatibility can not be
underestimated; the choice of which MCU
family to adopt today is based largely on the
quality of the software development tools and
the availability of software libraries. Microchip
continues to develop software applications
and make them freely available to customers,
including advanced communications protocols
for the PIC32 family.
For the many existing PIC® users now
evaluating 32-bit MCU solutions, the PIC32
represents their simplest transition. It offers
an almost seamless move from 8- and 16-bit
devices to high performance processing. For
a wide choice in performance, a familiar and
compatible development environment, the
PIC32 family is unsurpassed.
There are many 32-bit solutions available, all
claiming to offer the highest performance
when measured against a specific parameter.
However, for your application, only one
solution is truly the best; the key is to find it.
Independent benchmarks are an excellent
starting position and in this respect the PIC32
is unbeaten, but why leave it to chance? RS
offers a range of development kits for all
leading 32-bit solutions, allowing engineering
teams to evaluate devices using real life
applications; your own benchmark.
Higher
performance
Low
power
Faster
processing
For more information or to check
out the range of development kits
available, visit rswww.com/electronics
38
eTech - ISSUE 3
eTech - ISSUE 3
39
LUNCH
BREAK
WIN
LUNCH
BREAK
a Garmin Nuvi 255W GPS
with our killer sudoku
Daily No. 1513
24
Easy
10
23
11
Name:
Job Title:
16
11
How to play:
As with standard sudoku, every row and column and 3 x 3
square must contain the numbers 1 through 9 exactly once.
10
7
15
15
20
Ship-To-Number:
Tel:
10
E-mail:
11
The grid is composed of shapes with a dotted outline. At the
top of each shape is a number, this signifies the sum of the
cell. For example; if there is a shape composed of two cells
with a ‘3’ in the corner, the total of those cells is ‘3’. From that
you can tell that the values of the cells must be ‘1’ and ‘2’ or
‘2’ and ‘1’.
31
18
17
18
It is not permitted to repeat a number in a shape. If you have
a sum of 8 across three cells, this cannot be ‘2’, ‘4’, ‘2’ as the
‘2’ is then repeated
in the shape.
18
6
15
No numbers are placed in the grid to start with, unlike in
normal sudoku; however you can work out every number
with no guesswork but applying logic alone to reach the
unique solution for each puzzle.
11
24
5
19
7
16
17
Send your completed Sudoku to:
RS Components Ltd, eTech Team, DPN 24, Corby, Northamptonshire,
NN17 9RS.
Terms & Conditions:
This competition is being run by RS Components Ltd. To enter the
competition, all information on the entry form must be supplied.
Entry is free, no purchase is necessary. It is the responsibility of
the participant to gain permission from his/her employer to enter
this competition. The prize is as stated. No cash alternatives are
available. The competition is open to all RS Components catalogue
recipients, except employees of RS Components or their families.
The closing date for entries is 01/09/2010. The date of the draw will
be in the month of September 2010. The winner will be selected
at random by RS Components and will be notified by 1st October
2010. Responsibility cannot be accepted for lost entries, damaged
or delayed in transit to the porters address. Illegible, altered or
incomplete entries will be disqualified. Details of the prize winner
can be obtained from the promoter after the date of the draw by
sending an SAE to RS Components, eTech Team, DPN 24,
Corby, Northamptonshire, NN17 9RS or by visiting
www.rs-components.com/etech.
Copyright (c) 2009, killersudokuonline.com
Where will you take YOUR eTech?
Broadcast to the Nation Quiz!
Our very own Pui Chueng launches
our new competition “Where will you
take YOUR eTech?”
Pui climbed Mount Kilimanjaro earlier this year
and was snapped with her copy of eTech when she
reached the peak.
Can you beat this?
Are you going to the pyramids, diving with sharks
or trekking in the jungle?
Send your photographs along with your name and
company via email to [email protected]
The best photo(s) will be printed in the next edition.
You may submit up to 5 photos per eTech issue. Entries must be clearly labelled
with your name and company details and be sent from your company e-mail
address for verification. Entries from a personal e-mail address may not be
used. All entries must be your own original work and must not infringe anyone’s
privacy or copyright or breached any laws. You must have obtained permission
of any people featured in the photo, or their parents or guardians if children
under 16 are featured. By entering your photo, you allow RS Components to
edit and reproduce your photo along with your name and company details in
any media in all countries. RS is under no obligation to publish your photo.
40
eTech - ISSUE 3
Answers can be found at
1
2
What video standard is
used in the UK?
a.
What does NTSC stand for?
a.
3What is the standard aspect ratio
of a widescreen television?
a.
4How many frames per second
(FPS) does a PAL signal contain?
a.
www.rs-components.com/etech
5What does DVD stand for?
a.
6
What Does HDMI stands for?
7
8
a.
9
What is the furthest distance at which the human ear can detect audio frequencies?
a.
10Phantom power is a means
of what?
What does CCD stand for?
a.
a.
Where does the term “vox pop” come from?
a.
eTech - ISSUE 3
41
INDUSTRY
NEWS
A Mini-laboratory
for all cases
Many illnesses can be reliably diagnosed through laboratory tests, but
these in vitro analyses often use up valuable time. A system developed
by Fraunhofer research scientists, which can carry out complex
analyses on the spot, will soon be ready for the market.
“We’ll just have to wait for the results of the laboratory tests”.These
words are familiar to many patients. It then usually takes several days for
specimens to be sent to the laboratory and analyzed and for the doctor
to receive the results. For many illnesses, however, a speedy diagnosis
is crucial if the treatment is to be successful. In future, the patient might
only have to sit in the waiting room for a few minutes until the results
are ready. In a joint project, researchers from seven Fraunhofer institutes
have developed a modular platform for in vitro diagnosis which enables
various types of bioanalysis – of blood and saliva for example – to be
conducted in the doctor’s surgery. “Thanks to its modular design our
IVD platform is so flexible that it can be used for all possible bioanalytical
tasks,” states Dr. Eva Ehrentreich-Förster from the Fraunhofer Institute
for Biomedical Engineering (IBMT) in Potsdam-Golm.
The core element of the mini-laboratory is a disposable cartridge made
of plastic which can be fitted with various types of sensor. For an
analysis the doctor fills the cartridge with reagents – binding agents
which indicate the presence of certain substances such as antigens in
the specimen material. Various tests or assays are available for different
types of analysis. To perform an assay, the doctor only has to place
the relevant substances in the cartridge and the test then takes place
automatically. “We have optimized the assays so that up to 500 assay
reactions can be conducted in parallel in a single analysis step,” explains
Dr. Ehrentreich-Förster. Even in the case of complex analyses the doctor
obtains a result within about 30 minutes. A new module on the reverse
side of the cartridge also makes it possible to analyze the specimen
material at DNA level.
Once the cartridge has been prepared, the doctor places it in the
measurement system. The results can be read out with either optical
or electrochemical biosensors. The researchers have installed a readout
window for both methods in the measurement system, which features
a bypass through which the specimen is pumped.
In addition to medical applications, Dr. Ehrentreich-Förster has other
markets in her sights. “The IVD platform is also suitable for food
analysis and doping checks.” The mini-laboratory will soon be ready
for the market.
42
eTech - ISSUE 3
Thanks to its modular
“design
our IVD platform
is so flexible that it can
be used for all possible
bioanalytical tasks
”
Dr. Eva Ehrentreich-Förster from the
Fraunhofer Institute for Biomedical
Engineering (IBMT) in Potsdam-Golm
New left and right hand plugs
New left and right hand plugs have been added to Tyco Electronics’ line of
wire-to-board, Eurostyle terminal blocks. This product extension provides additional
configurations of wire access angles to the standard 3.5mm and 3.81mm vertical and
right angle headers. Specific applications of this product include control, input/output
and field wiring.
We’ve added over 4,000 Vishay products,
giving you an ever expanding choice.
A key feature of the plugs is their multiple wire access angles which mate with 90° and 270°
header interfaces. Their rising, screw clamp orientation mates to industry standard open and
closed end headers on the same centerline spacing. In addition, they are
end-to-end stackable without loss of centerline spacing.
The plugs are UL recognized and serve the industrial control, communication equipment,
and HVAC control markets. Other product options include custom marking, printing and
color selection.
rswww.com/Tycoelectronics
TE (logo) and Tyco Electronics are trademarks of the
Tyco Electronics group of companies and its licensors.
rswww.com/vishay 08457 201201
e
YOUR ELECTRONICS MAGAZINE ISSUE 3
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