Designing Embedded Systems for Industrial Applications

Developing embedded systems with current high-performance processors requires considerable detailed knowledge and acquiring new technologies. Many crucial decisions have to be taken right at the start of a project:

  • Are all required I/O interfaces available and simultaneously accessible? Does the internal routing provide sufficient bandwidth to service these peripherals in time?
  • Which memory technology should be used? Will these devices be available in the long term?
  • Does the technological know-how and the required circuit design and PCB layout tools exist, e.g. to control the impedance and match PCB trace lengths as required by modern synchronous memory interfaces and high-speed serial peripherals?
  • Which operating systems are supported, and how much customization is required if the design deviates from the reference design?
  • Are all hardware drivers available or purchasable, or must some of them be implemented in-house?
  • Do all measurement facilities exist to put the system into operation and for production? Are the employees appropriately qualified?

These questions often relate to knowledge areas far away from the key expertise of a company. The expenses required for development will not necessarily be reflected in product improvements, visible and honoured by the end customer. Companies therefore tend to resort to external development resources, often multiple partners for hard- and software. Besides being a costly approach, it is often difficult to integrate this externally sourced technical knowledge into your company, making it difficult to ensure the long product lifecycle as well as not having the agility the react quickly in producing necessary adaptations.

D.SignT products simplify your decisions by:

  • highly integrated middleware, with all processor subsystems assembled on a single system-on-module.
  • tightly specified external interfaces and drivers
  • a modular approach which is usable throughout the entire project, from feasibility study to series production, thereby significantly reducing your risks while migrating to the next project stage
  • long-term delivery and hard- and software compatible upgrade options, should the system requirements be increased during product lifetime
  • qualified consultation, support and broad experience with the special demands of industrial real-time systems

... in Detail

Processor Selection

Current processors for the embedded market shine with a wide variety of integrated peripherals and high computational performance, yet low cost. A second glance however may reveal severe restrictions for a particular application: pin-multiplexing inhibits the simultaneous use of interfaces, a central data path routing matrix imposes bandwidth limitations, instead of well documented interface descriptions the manufacturer refers to fee-based third-party driver software.
To avoid erroneous assessments, significant time for familiarization, evaluation and training has to be accounted for. Evaluation systems are often laid out only for the most typical application area. Lack of expansion possibilities makes design verification and prototyping even more difficult.

D.SignT has gathered an in-depth knowledge of the processors used on the D.Module boards and the accompanying tools. We can provide qualified consultation on selecting a suitable processor. With D.Modules we offer a versatile platform for highly accurate evaluation and prototyping, as well as being usable as a series production component, thereby considerably minimizing your design risks.

Long-term availability

Industrial embedded systems typically require a product lifetime of 10 years or even more. The availability of several components will turn out to be critical. Especially memories (DRAM and Flash), but also switch-mode power supply controllers and some interface devices may become obsolete during product lifetime. Redesigns and costly inventory of critical components may be required. Hardware redesigns will also make software changes unavoidable, which may present further complications: the tools used during development may cease to work on new operating systems, the new tools with refined optimization strategies will generate different codes which require additional validation.

D.SignT has taken precautions: all configurations and initializations are handled by the D.Module.BIOS firmware. If components need to be changed during lifetime, the BIOS is adapted accordingly. The BIOS also provides initialization and I/O functions for interfaces, which are also adapted, should an interface circuit become obsolete. The user will not notice these hardware and firmware changes, no adaptations of the application program is required.

Long-term availability also includes upgrade options: Most systems will be further refined and optimized during product lifetime, new features will be added. The system might run short of memory resources or computing time. The standardized D.Modules provide a straightforward upgrade and migration path without requiring expensive hardware redesigns.

Advanced Technologies

High-end processors impose stringent requirements on the external interface timings: High speed can only be achieved by controlling PCB trace impedance and matching of trace lengths. Additionally the high clock and interface speeds and multiple power supplies present additional EMC difficulties - RF layout skills are required.
To achieve the targeted trace impedance gaps between neighbouring PCB layers must often be less than a few 100µm. This often contradicts the safety requirements for certain external interfaces, e.g. isolation and dielectric strength. The PCB technology required for the DSP and FPGA part is expensive, but will only be used in a small area of the entire system. It is therefore obvious to spin off the DSP part into a separate add-on board.

Operating Systems and Drivers

Operating systems and interface drivers do require adaptation to the target hardware. If this differs from the evaluation platforms, the user must adapt the RTOS configuration, bootloader, drivers etc. himself. This is a time consuming task and is often complicated by documentation quality, since the processor manufacturers tend to outsource more and more software to third parties.
D.SignT continously adapts their products to the latest versions of the development tools and operating systems.

Production and Testing

Production of DSP and FPGA systems requires special qualifications and advanced measurement equipment to detect, identify and repair unavoidable production flaws. D.SignT boards are fully tested and can be replaced easily in case of failure.

A further problem might not show before the end of the development phase: DSP manufacturers only offer limited tools to create boot images and transfer these to the target hardware. Additional tools and qualifications may be required in fabrication.
Besides, the standard bootloaders do require adaptation to hardware changes, e.g. if memory devices are changed throughout product lifetime. D.SignT products include a unified bootloader which allows straightforward uploads of the application programs via a USB and/or a serial connection. This bootloader does not require special hardware or tools and is independent of hardware dependencies. For field maintenance all D.SignT boards provide predefined BIOS functions which allow to upload program and parameter files to the flash memory from various sources like USB and Ethernet.

Conclusion

D.SignT is aware of the special problems in development, production and maintenance of embedded systems in an industrial environment. D.Module minimize your development time, design risks and maintenance effort.