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FROM EDN EUROPE: Low-cost ARM kits ease 32-bit migration

With 32-bit microcontrollers now so cheap that they rival 8-bit devices in value-for-money terms, a new generation of low-cost evaluation tools displaces traditionally expensive development systems to ease entry into high-performance embedded computing.

AT A GLANCE 32-bit evaluation kits break the $250 marker. Targets span analogue microcontrollers to multimedia engines. Multiple development-environment choices suit user preferences. Low-cost JTAG emulators support non-intrusive debugging. Self-training materials complement free code libraries. Full-featured environments won't break the bank. Sidebars: Simple steps save frustration

For many embedded-system designers, 2005 finally marked the arrival of
an array of 32-bit microcontrollers at unprecedentedly low cost. For
instance—and as we reported in last December's EDN Europe—at $1.47/10,000, Philips set a new
low price point for the ever-popular ARM architecture with its LPC2101
(href="#refs">Reference 1). This development complemented a
host of general-purpose ARM-based microcontroller releases from semiconductor
suppliers. At the same time, prices for entry-level devices for proprietary
architectures such as Analog Devices' Blackfin fell to the $5 level. But it's
not much good having highly affordable chips if you can't afford the
development tools, which have traditionally been priced at over $10,000 for
many 32-bit environments—and no one spends this kind of money without
being absolutely confident that their investment is worthwhile.

As a result, the great majority of semiconductor vendors have woken up
to the fact that making products accessible in the first instance is crucially
important to secure design wins. All of the companies that we contacted in our
December feature stressed the importance of product support, and all offer
either their own or third-party evaluation kits to showcase their silicon.
Bundling evaluation copies of compilers, debuggers, and
integrated-development-environments from software toolmakers such as Green
Hills, IAR, Keil, and Tasking gives engineers the opportunity to try these
tools before committing to multi-thousand-dollar full-specification compiler
purchases. The emergence of on-chip emulation support complements the trend
towards lower cost in-circuit emulation, and there are now numerous USB/JTAG
devices that permit non-intrusive hardware debugging for orders of magnitude
less cost than traditional systems for 32-bit architectures.

Engineers who invest countless hours in becoming familiar with
development environments and the architectures that they support need
compelling reasons to migrate to new alternatives. Yet one of today's biggest
trends is the shift away from 8-bit machines such as generic 8051 derivatives
in favour of 32-bit devices that now offer similar micro-controller variety at
little extra cost. Confirming this trend, a report in Electronics Weeklyrecently quoted market researchers
In-Stat's expectation that by 2009, the combination of 16- and 32-bit revenues
will be about twice that of 8-bit devices (href="#refs">Reference 2). In-Stat cited the sophisticated features that routinely appear
in consumer products as the key driver for migration to wide-datapath cores,
noting that higher bit-width microcontrollers require less power than 8-bit
devices to do a given amount of work. This is an area where the ARM
architecture excels, helping to explain its dominance in portable
electronics.

32-BIT CPUs - BEST VALUE?

For engineers working within automotive and industrial spheres, it's
typically the raw functionality and deep on-chip memories that 32-bit machines
provide that justify making the transition from tried-and-trusted 8-bit
devices. Given the low price of 32-bit silicon, it's then germane to question
the role of 16-bit machines—especially when devices that employ the
ARM7TDMI core bundle a 32-bit CPU with a multiplexed 16-bit external
address/datapath that offers cheap memory and peripheral connectivity. Helping
to tempt you towards this route, a new generation of affordable entry-level
tools endeavours to smooth migration issues into traditionally complex
environments. So how approachable are these tools, and how well do they compare
with user expectations?

To find out, we invited several key players to submit evaluation kits
for ARM-based microcontrollers that suit automotive and industrial
applications, with the only limitation being a price ceiling of $500 per kit.
The respondents comprise Analog Devices, Atmel, Freescale, and ST
Microelectronics, all of whom recently released new silicon that our feature of
last December describes. That feature introduces the ARM7TDMI architecture and
includes full details for all of the chips in this review. Each microcontroller
targets application niches that we'll examine with the help of the resources
that come in the box or are available as free web downloads.

The main host PC for these tests is a deliberately typical 2.4 GHz
Pentium-4 with 512 Mbytes of RAM, 10/100 Mbps Ethernet, two USB ports, two
serial ports, and a parallel port. Separate DVD read and write drives
complement dual 80-Gbyte hard disks that hold dual installations of Windows XP
Pro SP2 and SuSE Linux Professional 9.3. A second very similar PC running
Windows 2000 Pro came into play to avoid corrupting or erasing working examples
of similar development environments. It's worth noting that as tested, none of
the environments that follow are compatible with Windows 98.

Importantly, each evaluation kit receives two days maximum of
exploration time, which should be long enough for the designer to become
reasonably familiar with what's on offer. Because the ARM7TDMI core often isn't
the best fit for hard real-time applications or for intensive DSP work, an
upcoming feature examines proprietary architectures using an identical
evaluation kit approach—balancing the generic ARM focus in this article
while also presenting alternative solutions for low-power applications. Any of
the boards tested in this feature that present compelling reasons to extend the
two-day limit will receive a progress update in the later feature. Meantime,
see the sidebar "href="#SIMPLE STEPS SAVE FRUSTRATION">Simple Steps Save Frustration" for hints and tips to speed your own evaluation processes.

COMMS CHANNEL BRIDGE

Atmel's latest ARM-series evaluation kit is the AT91SAM7XC-EK that
showcases the company's new AT91SAM7X processor. Designed as a communications
bridge, this 100-pin chip features CAN, Ethernet, RS232, and USB interfaces,
together with hardware support that offloads communication-channel processing
overheads from the CPU. The $249 kit contains the evaluation board, an 8-Mbyte
Flash card, USB cable, and crossover Ethernet and RS-232 cables. The system
documentation and other resources reside on a DVD. There's also a
universal-input USB power-supply adapter, complete with US and Continental
two-pin plugs. Because the board only accepts power via the USB socket, the USB
power supply is helpful when using the JTAG interface for debugging. Be sure to
budget $129 for the SAM-ICE in-circuit emulator, which the kit does not
include. An Atmel-branded version of Segger's J-Link, the device is
next-to-essential, and substantial parts of the DVD's contents require its use.

Available with either 128 or 256 kbytes of Flash, the board carries the
processor with the larger on-chip memory. The lack of other chips is testament
to the integration that the processor provides—this chip apart, there's
a 32-Mbit Atmel serial Flash device, a Philips CAN transceiver, a Davicom
Ethernet physical-layer interface, a pair of RS232 interface chips and a
rail-to-rail op-amp from Analog Devices, a voltage reference, and a voltage
regulator. The interface chips support the board's wealth of I/O ports,
including a three-pin analogue interface connector, a CAN port, two nine-pin
D-connectors for the RS232 and serial-debug ports, a standard Ethernet socket,
and a USB device port. There's also a 20-pin header for the JTAG in-circuit
emulator, a slot for the Flash card, and a 0.1in.-pitch, three-row 96-pin
expansion connector. A four-axis joystick accompanies the usual complement of
LEDs and jumpers.

The "getting started" screen that opens in a web browser offers users
the opportunity to explore software-development environments from IAR Systems,
Keil, and Green Hills. The role of the joystick soon becomes clear—a
general-purpose user-input device, it also simulates a mouse. Having chosen to
install Keil's mVision 3, it's also necessary to add an update patch. The next
steps install software support for the AT91SAM-ICE in-circuit emulator, without
which the kit provides very limited access to the processor. For some
unfathomable reason, Atmel chose not to supply this part with the evaluation
board, requiring a last-minute search around the UK's distributors to locate
one. Thanks to Kim at independent distributor GD-Technik for persuading her
warehouse to ship its last example before the seasonal break.

The DVD that accompanies the SAM-ICE contains device-driver software
along with a huge amount of information that pertains to the SAM7X's
predecessors. Much of this information is still highly relevant and invaluable,
but the board's own DVD mirrors the literature version while offering a number
of updates. For instance, there's a series of PowerPoint presentations that
describe aspects of AT91 operation, from C-code start-up considerations through
operation of the family's extensive set of peripherals. There are also example
programmes and a mass of application notes, Linux resources, evaluation copies
of third-party toolsets, and even board-design files complete with an
Orcad-format library. The SAM-ICE device drivers appear in its
tools subdirectory. When Windows installs
these files, the SAM-ICE's LED stops flashing and a success message appears on
screen. Click on the jlink.exe hyperlink in
the browser's set-up window and a DOS window appears to report a successful
firmware upgrade. This window echoes firmware revision status, identifies the
device by its serial number, and states RDI against the Features line—signalling that the hardware
complies with the remote-debug-interface specification. This is significant
because the SAM-ICE seamlessly integrates RDI support into the target
environment, although some restrictions become apparent.

Unzipping a self-extracting project file creates a template to set up
the Keil environment. This DVD-resident file creates a new directory, which you
then have to point the Keil interface towards—first enabling
see all files to reveal the crucial
.uV2 extension. The on-screen instructions
step through set-up parameters for the SAM-ICE, after which the device is ready
to use. With the SAM-ICE and USB power supply connected, it's now time to run
the Getting Started example project. Four
sequentially blinking LEDs signal success. The next exercise burns this
programme into Flash, which requires a USB connection to the PC and the
installation of Atmel's SAM-BA Flash burner utility. All of these steps
completed seamlessly, leaving the system components correctly set up for future
use.

Wondering why Atmel promotes its own Flash download mechanisms rather
than using the SAM-ICE revealed that an extra-cost Segger licence is necessary
for this connection, for the Keil environment at least. Other extra-cost Segger
options for this and the J-Link emulators in other kits include the company's
J-Link RDI FlashBP software that allows setting multiple breakpoints in Flash.
The software costs a substantial €398 within its standard licensing
schemes.

During an attempt at familiarisation with the Keil environment and its
Flash abilities, the board's USB connection inexplicably failed. Subsequent
probing established that the SAM-BA connection to the serial debug port
continued to work, as did the SAM-ICE. Suspecting that this fault was due to
corrupting the Flash that holds boot code, it was disappointing to find that
the Recovery Procedures web page heading at
www.at91.com—where you will also find a
very active user forum—was empty for this board. Jean-Philippe Moreno at
Atmel's AT91 support team advises that the correct procedure to recover
SAM-Boot into the on-chip Flash memory
consists of closing the TST jumper (JP5), powering up the kit, and waiting 10
seconds before re-booting.

It also appears that for this kit, the greatest compatibility comes from
choosing the IAR toolchain. SAM7X-specific code examples comprise an interrupt
handler and a CAN transmitter/receiver routine (Figure
1). This is a significant development for Atmel, which in the
not-so-distant past has charged as much as $2500 for CAN driver packages to
support earlier-generation silicon. There are also two encryption/decryption
routines for the XC processor variant that includes scrambler hardware. These
routines appear within the DVD's Software
Package section, where a generic start-up template also exists for
each of the software environments. Installing the 32-kbyte-limited Kickstart
edition of IAR's Embedded Workbench mirrored the on-screen set-up procedure,
which terminates with burning the Flash image via the SAM-ICE without the need
for extra-cost licenses. The installation routine builds a 190-Mbyte
subdirectory that contains IAR-specific documentation such as user manuals,
together with an AtmelExtras folder that
contains the code examples. In operation, the JTAG debugger routinely
autoconnects at an impressive 4 MHz that provides enough responsiveness for the
great majority of applications that don't demand hard real-time responses. Any
of the routines tested ran faultlessly, complementing the extensive training
materials that help to differentiate this kit. Other evaluation-kit designers
would also do well to follow Atmel's example in adding full-size ground
terminals to allow easy connections to test equipment.

If the 32-kbyte code limit within this or any other IAR Kickstart
edition proves insufficient, the tools supplier offers options for all of its
ARM-derivative environments. These range from its 256-kbyte-limited baseline
version that costs €2200 to its unrestricted €5000 professional
edition. The latter version includes 12 months' technical support, network
options, and UML documentation facilities. Interestingly, IAR is also working
on its own high-performance JTAG debugger that will be available in Q3/2006,
with a target price below €1000.

5V SILICON suits industry

Available now for €260—or approximately $299—the
IAR-branded package that contains the STR730-SK/IAR Kickstart Development Board
kit is another comprehensively featured environment. It demonstrates
STMicroelectronics' latest ARM7TDMI-based family, the STR730 built with the 5V
silicon that industrial and automotive designers typically favour. Removing the
sleeve reveals two boxes, one of which contains a J-Link emulator
that—colour and branding apart—appears identical to Atmel's
SAM-ICE. This version, however, routes 5V to the board from the host PC's USB
port via pin 19 of the 20-pin JTAG connector that's unconnected in typical ARM
environments. As supplied, the emulator also uses dedicated J-Link rather than
RDI drivers. The second box houses IAR's STR730-KS board, a CD-ROM, and an
adapter to match the 3.3V J-Link emulator to the microcontroller's 5V
levels.

The board seemingly consists of connectors and not much else: apart from
the top-specification STR730FZ2 processor that houses 256 kbytes of Flash, 16
kbytes of SRAM, and three CAN interfaces within its 144-pin outline, in
chip-count terms there's a pair each of RS232 and CAN transceivers, together
with a bridge rectifier and 5V regulator for the optional external power input.
Like every kit here, the documentation includes schematics. In this case the
circuit prints legibly to one A3 page, attesting to its hardware simplicity.
Peripheral devices include a two-line 16-character LCD, four signal pushbuttons
and a reset switch, a potentiometer to adjust an analogue-input level, a
thermistor, a buzzer, and 16 LEDs. Two CAN ports, four RS232 ports, two
I²C and two SPI ports, as well as
headers for the processor's Port-4 and analogue input surround three edges of
the board's 180×130 mm outline. There's also a row of pin headers that
connect with various I/O lines and a prototyping area (href="contents/images/6301710f2.pdf">Figure 2).

Running the installation routine builds a 196-Mbyte subdirectory that
holds much the same contents as its Atmel-specific version, including the
all-important user manuals. Additional features include a 20-state version of
IAR's VisualState application, which includes an automatic code generator with
the stealthy ability to construct output from analysing machine states.
Target-specific code-example directories for a host of processors appear under
the arm/src/ subdirectory of code examples,
including the LCD routine that serves to introduce the system. The lack of a
bill-of-material obscures the origin of the LCD module, but it seems to be a
standard HD44780-compatible device with the chip-select,
R/W, and RS lines that strobe in data bytes from a four-bit
interface port (see
http://home.iae.nl/users/pouweha/lcd/lcd.shtml).

While the installation process completed satisfactorily with all
drivers, set-up parameters, and switches apparently correctly set, the J-Link
emulator refused to communicate with the target board, returning "could not
find a device on JTAG chain". Swapping cables and trying the system on another
PC that has no previous IAR or J-Link installations returned the same result.
The installation didn't include the J-Link manual or the useful-looking
jlink.exe utility that are available from
Segger's website—along with updated drivers that also failed to
resurrect the system. 'Scoping out the emulator's JTAG output lines revealed
that TCK remained high at all times,
suggesting a fatal hardware fault. Contacting Product Support revealed
(embarrassingly) that your reviewer had installed the adapter board at the
target-board end of the cable, not at the emulator end—effectively
reversing the adapter. The IDC connection system makes it possible to wrongly
connect the components. It's an easy mistake to make as the in-circuit emulator
comes with the 20-pin cable attached, making it feel natural to plug other
parts into the far end. Our sample is a pre-release version, so expect to find
the jlink.exe utility included within later
versions, along with graphical instructions that even myopic contributing
technical editors can't ignore.

With this connectivity problem solved, the board immediately burst into
life by running the ADC demo routine that the emulator downloads into Flash.
Enabling the run to main debugger option and
single-stepping from there on in while checking views—such as the
processor's registers—effortlessly demonstrates the environment's power.
Furthermore, ST's website highlights its new software library that offers a
very good-looking support package, including an active user forum. Within these
pages appear software libraries for the STR730 as well as for the STR710/720
series, along with all documentation. The software library invaluably contains
C-code examples for all the chip's peripherals including the CAN ports,
together with start-up projects for ARM's RealView Developer, IAR's Embedded
Workbench, and Raisonance's Integrated Development Environment.

MIXED-SIGNAL 32-BIT µCS

While virtually every microcontroller routinely includes ADC support,
very few include the analogue blocks that make single-chip analogue processing
solutions a reality. A small but rapidly growing part of the microcontroller
landscape, mixed-signal processors have typically been 8-bit machines such as
the 8051-based products that Analog Devices and Silicon Labs offer. The
potential for more sophisticated applications using sensors and other analogue
sources led Analog Devices to introduce its ADuC702x family of ARM7TDMI-based
microconverters, which its EVAL-ADUC7026QSP kit demonstrates. The $249 box
contains the ADuC7026 board, a USB-to-JTAG in-circuit emulator and cables, an
RS232 cable with internal level shifters, 120 and 230V two-pin wall adapters, a
CD-ROM, and a getting-started booklet.

The two-layer board carries the processor, a 32.786-kHz crystal to
generate the phase-lock-loop's 45-MHz clock, 3.3V voltage-regulator and 2.5V
voltage-reference chips, a differential-input/output op-amp, a couple of op-amp
buffers, and two LEDs to indicate power-good and I/O-pin activity. An 8-way
switch offers connection options for the chip's I/O, while three pushbutton
switches provide reset, IRQ, and serial download functions. All I/O is
accessible from an array of headers. A small demonstration circuit comprising a
potentiometer and an LED helps exercise the board's set-up procedure. Pads
allow users to add a 16-bit latch to demultiplex address/data for optional
64-kbyte SRAM and 128-kbyte Flash memories. A prototyping area fills the rest
of the board's 127×102 mm outline.

The CD-ROM's install routine offers a choice between IAR and Keil
software environments with no obvious bias towards either—both offer
non-intrusive JTAG debug connectivity via the RDI-compliant Midas-Link
emulator. Examining the available software reveals a full GNU toolset for the
Keil option, to which the set-up tool and the documentation's commentary
defaults. Following this path installs version 2.40c of this environment with
additional support for the ADuC7000 series, which offers a comparatively meagre
16-kbyte code limit. It should also silently install the GNU toolchain, but
this step required manual intervention. A new directory appears that contains
system documentation, code examples, and tools that notably include
Elves.exe, a configuration utility for the
chip's peripherals that isn't automatically installed. The installation process
does however add the PLA tool for configuring the programmable-logic-array
within ADuC7000-series devices together with a serial-port Flash memory
download utility, both of which appear separately under the ADuC702x start-menu
entry. The PLA block provides for simple combinational logic control of, say,
ADC triggers.

Plugging in the Midas-Link emulator reveals that it too is a Segger
device—Windows recognised the device, having previously installed the
Atmel-badged version, and automatically assigned the same J-Link driver. The
instructions move on to starting a new project, which builds a set-up file
complete with parameters for the emulator and the environment for future use. A
quick tutorial follows that shows how to add and link a new file to build an
application, using as an example one of the chip's DACs to stimulate an ADC
channel and return a reading. It's now helpful to examine the Elves facility
that holds the promise of simplifying peripheral set-ups. You can run this
programme in standalone mode, or integrate it within the IAR or Keil
environments by adding it to the Tools menu within these suites. In operation,
Elves presents a browser of library functions that you select from a pull-down
list, each of which contains a subset of functions. For instance, the UART
library includes getcharand
putchar C-function prototypes, among others
that set-up and manage the port (href="contents/images/6301710f3.pdf">Figure 3). As
well as being simple to use, this system allows users to add their own function
libraries providing that they follow a few simple rules that appear in the help
menus.

Exploring the code subdirectory
reveals a wealth of project examples for the GNU, Keil, and IAR environments.
Positively the simplest is blink, a ten-line
routine that alternately turns a LED on and off via a GPIO line. There are
separate examples for serial communications comprising I²C, SPI, and using the UART to complement those
that describe the chip's analogue peripherals. Further examples include memory
manipulations from placing and running functions from internal/external RAM,
through programming and erasing Flash, to placing variables in memory using the
GNU compiler. Each code segment is sufficiently simple or has enough inline
commenting to be easy to understand, and examples run easily.

LINUX DRIVES MULTIMEDIA

Designed by Cogent Computer Systems, Freescale's i.MX Litekit just
scrapes into our $500 limit with one dollar to spare (suggested retail). It
distinguishes itself in several other respects too: targeting multimedia
applications, its two boards feature a 200-MHz MC9328MXL processor with an
ARM9-derived core; it offers a QVGA graphical touch screen LCD that the
processor drives directly, as well as audio capability via a Wolfson codec; it
uses Macraigor Systems' usbDemon debugger, an alternative to the JTAG
in-circuit emulator interfaces that other products in this article offer; and
it comes with a full set of Linux-based tools from Microcross that the
company's website prices at $1000. All of these capabilities suit automotive
and industrial applications from infotainment to complex man-machine interfaces
(see Figure
4).

The box contains null-modem RS232, normal and crossover Ethernet, and
mini-USB cables, plus a universal-input power supply and a CD-ROM that presents
third-party development-support options. The dual-board format consists of a
tiny CPU module atop a baseboard that measures about 100×100 mm and
carries all I/O, except a mini-USB-format JTAG port that the CPU uses for the
Macraigor debugger. Hardware highlights include 64 Mbytes of SDRAM, 8 Mbytes of
Flash, slots for Compact Flash and secure digital/multimedia (SD/MMC) cards,
the Wolfson stereo codec, and serial, 10 Mbps Ethernet, and mini-format USB
device ports. There's also a standard 20-pin JTAG debugger header plus a
full-size USB port marked "host" that the design seemingly does not use. The
tools install under Windows NT4/2000/XP and Linux for Intel i586/686
architectures—preferably Debian, Linspire, or Red Hat, whose recent
versions Microcross has tested for compatibility. Notice that the Macraigor
debugger only runs under Windows.

A readme file on the i.MX GNU X-Tools
CD-ROM describes the software-package contents. This comprises a full GNU
compiler toolsuite for the ARM/Thumb processor architecture for OS-less, RTOS,
and Linux application development. The constituent parts include ARM/ELF and
ARM/Linux compilers, an assembler, debugger, and simulator, the VisualGDB
debugger, and libraries. There's also a copy of the Cygwin environment that
simulates Linux on Windows hosts—see EDN
Europe's recent embedded Linux feature (href="#refs">Reference 3). Exploring the docs subdirectory reveals a
hardware reference manual for the CSB536FS CPU module and its CSB936FS breakout
board, the X-Tools user guide that contains software-installation instructions,
and various documents that relate to system components such as the Macraigor
debugger. It's noticeable that while the Cogent hardware manual extensively
describes I/O connections and gives accurate overviews of the base board's
layout, it fails to describe the switches and LEDs on the CPU board—the
figure is simply missing, reflecting just how new this kit is.

To install the support environment, Windows users should simply let the
Microcross i.MX GNU X-Tools CD-ROM autorun. This process installs a 750-Mbyte
Cygwin directory structure that transfers
all the examples and documentation, including the i.MX GNU X-Tools User Guide.
The installation routine creates two desktop shortcuts—i.MX GNU Tools Shell and XWin, both of which are command-line interfaces. Linux
users will first need to refer to the CD-ROM copy of this document for
installation instructions. In both cases, sections two and three of this really
very good manual continue by explaining how to install the tools and establish
communications. The most straightforward connection is 38.4-kbps serial via a
terminal programme, such as Windows HyperTerminal. Connect the null modem
cable, invoke HyperTerminal, power up the board, and the MicroMonitor startup
dialogue appears with its uMON> command
prompt. This connection accesses the onboard boot monitor program that a
300-page user manual describes. The boot program sets numerous I/O parameters,
powers up the LCD, and reports the board's IP address. MicroMonitor promises to
save developers massive amounts of time by using its calls to configure and
control I/O.

The X-Tools guide shows how to change the network settings to suit the
target environment. Because the board's TFTP (trivial-file-transfer-protocol)
communications require fixed values, it's advisable to set static server IP
addresses if your network runs DHCP (dynamic host configuration protocol).
Remove power, plug in the crossover Ethernet cable, re-apply power, and it
should be possible to use Windows' ping to
check the board's Ethernet connectivity at the IP address you set—which
MicroMonitor should also report. Alternatively, dispense with the peer-to-peer
crossover cable to a PC and plug the board straight into a hub. The user guide
steers you through building and loading an application first using
MicroMonitor, then GX-Linux. The first process failed, reporting
make: *** No rule to make target 'dld'.
Stop. The reason for this problem remains unclear at press time. By
contrast, the complex GX-Linux process worked faultlessly, building the
environment and uploading it to the board's Flash. Typing
startlinux invokes the environment and
readies it for running the test programs.

To configure the usbDemon debugger, you now install OCD Commander, a
piece of Macraigor freeware that's deposited under the Cygwin tree. Installing
this software adds another two desktop shortcuts, together with two drivers
that enable usbDemon to communicate—which the usbDemon Finder utility
proves by flashing a LED on the CPU board and returning a device serial number
that's needed to invoke OcdRemote. This standalone utility runs under the
X-Tools shell, listening to a TCP/IP port and converting incoming GDB-debugger
commands to JTAG signals. To get this to work, the documentation describes how
to make a test program within the X-Tools shell prior to connecting the
null-modem and Ethernet cables. Invoke another instance of X-Tools and start
OcdRemote with a command line such as ocdremote
–c ARM920T –d USB –a 0 –s 1, when a
cryptic message appears that confirms that the utility is listening on its
default port 8888. Windows XP Pro also reports a 10-Mbps connection to the
board's low-power Ethernet port at this point. It's necessary to repeat this
connection process every time that you start a new debugger session.

With all communications established, it's now possible to run the
command-line GDB debugger or its graphical equivalent, VisualGDB. Typing
arm-elf-gdbtk test.x into the first X-Tools
instance selects the graphical option. It presents a familiar-looking windowed
environment, with typical commands such as set breakpoints and single-step
complementing views such as registers and memory (href="contents/images/6301710f5.pdf">Figure 5). This proves that the environment is set up and working, and it
will remain set until the user makes any changes. The console window provides
additional monitor commands to those available directly from the graphical
source window. The documentation continues to describe how to install and run a
30-day evaluation copy of Visual X-Tools, a $500 Microcross product that
seamlessly combines the GNU tools and debuggers within an
integrated-development-environment an option that's likely to appeal to
programming professionals.

From this point onwards, anyone who has worked with Linux before will
sense a familiar environment. Because it provides so many basic resources as
well as useful programming examples to control the board's I/O, it's essential
to master the MicroMonitor system as well as exploring the Linux environment.
How long the familiarisation process will take depends very much on individual
experience, but your reviewer simply ran out of time at this point. Watch out
for an update later on this year within our proprietary architectures
coverage.

---

For more information
Analog Devices: www.analog.com	ARM: www.arm.com	Atmel: www.atmel.com
Davicom Semiconductor: www.davicom.com.tw	Freescale Semiconductor: www.freescale.com	GD-Technik: www.gd-technik.com
Green Hills Software: www.ghs.com	IAR Systems: www.iar.com	Keil Software: www.keil.com
Lawicel: www.lawicel.com	Macraigor Systems: www.macraigor.com	Microcross: www.microcross.com
Peak-System Technik: www.peak-system.com	Philips Semiconductors: www.semiconductors.philips.com	Raisonance: www.raisonance.com
Segger: Microcontroller Systems www.segger.com	Silicon Labs: www.silabs.com	SofTec Microsystems: www.softecmicro.com
STMicroelectronics: www.st.com	Tasking: www.altium.com	Wolfson Microelectronics: www.wolfsonmicro.com

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Author Information

You can reach Contributing Technical Editor David Marsh at forncett@btinternet.com.

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References

Marsh, David, " href="http://www.edn.com/article/CA6288155.html">ARM targets automotive and industrial dominance ," EDN Europe, December 2005, pg 24. "War of the worlds: 16- and 32-bit MCUs invade ASIC applications," In-Stat 2005, Report price: $3,995, www.in-stat.com. Marsh, David, " href="http://www.edn.com/article/CA605681.html">Embedded Linux steals design wins ," EDN Europe, June 2005, pg 20.

Simple steps save frustration Testing different and often complex environments suggests several strategies that can ease the process, most of which are plain commonsense but also tempting to ignore. Firstly, consider your objectives—are you simply curious, or are you looking for a solution that will form part of your working environment for years to come? Users looking for upgrade paths from familiar environments will need to feel comfortable with new tools and also be certain of a reasonable degree of future-proofing, as it's both hard work and expensive to make wholesale changes to established practices. Questions that might apply to any evaluation kit include: What's in the box—and what's not—for what cost? Which facilities does the board provide? Which development environments are available—and are any of them familiar? How good is the supporting documentation—and is any other support available? Does the experience persuade me to use the vendor's products? If so, how much will it cost to upgrade to a full toolchain? With any new package, avoid the temptation to plug the board in straight away and rely solely on the quickstart instructions. Sometimes, a quickstart document provides the vital where-to-start link, but it always pays to examine the accompanying documentation and locate which resources are available to guide you—this step alone can save hours of frustration and wasted effort. Don't forget to include the manufacturer's website as part of this process. In particular, look for last-minute software patches and fixes to known problems, as well as software library and application note support. Also, see if there's a user forum and if so, check other users' feedback. If the kit offers multiple software environments—and unless you're very familiar with one of these—check to see if there's a surfeit of code examples for one in particular, signalling that the board was primarily designed with this environment in mind. When using the environment for the first time, start off with the simplest possible demo routine and take a good look around the environment's controls before writing your own code. At this juncture, it's a good idea to adapt example code if possible. If you're testing complex interfaces such as CAN, make sure that a piece of known working hardware is available to communicate with the board. Starting at around €100, an RS232- or USB-to-CAN adapter from vendors such as Lawicel or Peak can save hours—relying on two brand-new CAN-equipped evaluation boards to talk to each other is a sure recipe for frustration. Other frustrations include power supplies, or the lack of them. Check to see what comes in the bundle, including other essentials such as cables. Finally, be sure to allocate sufficient time to the project, which for serious users will necessarily be far more flexible than the uniform two-day limit here. While the main text conveys an impression of the relative complexity of the respective environments, it's fair to say that it's far quicker to become fully familiar with a straightforward kit such as the Analog Devices example than with than a complex Linux-powered environment such as Freescale's i.MX. Also, be sure to screen learning time—there's nothing more frustrating than getting the sense that a new aspect is falling into place and then being forced to drop the thread for some unnecessary interruption!