STM32 Journal - Digikey

STM32 Journal
consideration that the GUI may
need to be redesigned several
times. The sooner accurate user
feedback can be incorporated
into the GUI design, the more
confidence developers can
have that major changes will
not be required after significant
engineering resources have
been invested in implementing
the design.
GUI Testing
The iterative aspect of GUI design
is an important consideration when
selecting a GUI toolset. The speed
and ease with which developers
can modify an existing GUI will
determine how many design
iterations the schedule will allow
and, consequently, how well the GUI
will capture actual user behaviors.
Any testing process needs to
enable stakeholders and endusers
to provide timely input
into GUI design, preferably
as early in the design cycle
as possible. This means that
developers need access to rapid
prototyping capabilities before
target hardware is available. The
testing process should facilitate
the capture of user behaviors
and generation of use cases.
To achieve this, GUI tools must
accelerate design to shorten the
time between test iterations.
Traditionally, developers have
created simulated environments
for users to test. Often these
“wireframe” simulators are
independent tools that allow
developers to put together a
GUI but not necessarily one that
accurately reflects how the final
product will look or operate. For
example, because the simulator
is running on a high-speed
PC, screen updates can be
near instantaneous. Unless the
simulator is able to emulate the
MCU that will be used in the actual
product, developers will be unable
to verify whether the system is
responsive enough to satisfy users.
In fact, feedback from such testing
may actually mislead developers
and result in launch delays.
To ensure that the simulator
matches how the interface will
operate in production hardware
as accurately as possible, the
simulator needs to emulate the
operation of the target MCU.
Developing an embedded GUI
on a PC capable of accurate
emulation offers several benefits
to developers (see Figure 2). In
addition to speeding testing by
eliminating the need to download
new firmware to a target, the
simulator provides several
analysis capabilities to facilitate
optimization and debugging:
Figure 2 GUI design tools like the IS2T MicroEJ® simulator that is part of GWPack from
GeeseWare emulate the target MCU to ensure consumer testing matches the
operation of the production GUI as closely as possible.
〉〉 Static and run-time analysis of
timing and memory footprint
〉〉 Functional code coverage
〉〉 Task profiling and scheduling
Ideally, testers need to have
as realistic an experience as
possible. This means working
on a small screen the same size
as the one that will be used for
production. When running on a
PC, the user may need to use
a mouse rather than be able to
touch the device screen. Even if
a touchscreen is available, it is
likely the wrong size or a monitor
that the user cannot hold in his
or her hand.
To enable realistic testing,
GeeseWare offers its GWPack
development system. The
GWPack includes a standalone
and small form factor board
based on either the STM32-F2
or STM32-F4 that is prequalified
and production-ready. With a 4.3”
resistive or capacitive touchscreen,
10 ms response time, and access
in Java to all of the STM32
architectures peripherals and
interfaces of the pack, the GWPack
gives developers a fully operational
Java platform upon which to carry
applications from proof-of-concept
to production faster than has been
possible before.
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