Testing embedded software.


Testing embedded software always presents particular challenges as microprocessor driven systems work in combination with specific software which is often customised to the respective hardware. Thus, hard- and software are usually in-house development products. The areas of testware, test environment and validation of results in compliance with various ISO norms, such as DIN EN ISO 9001:2000,  DIN EN ISO 14001:2004 present further challenges.


The customer is a German manufacturer and international provider for energy and consumption data monitoring systems.

Two years ago the Linear Q™ system was first implemented within a project, to ensure quality by testing. By now this methodology is being used throughout all projects, whereby Linear Q™ itself presents the core and cornerstone of testing. The overall functionality of devices (device tests) as well as functionality of systems themselves (system tests) including networking components, read-out and diagnostic tools, are tested within this framework.

Short summary:

The following technologies/interfaces must work together and interact flawlessly:


"[...] IrDA provides specifications for a complete set of protocols for wireless infrared communications and the name "IrDA" also refers to that set of protocols. The main reason for using IrDA had been wireless data transfer over the “last one meter” using point and shoot principles. Thus, it has been implemented in portable devices [...]"

            Source: Wikipedia

M-Bus / OMS

"M-Bus (Meter-Bus) is a European standard (EN 13757-2 physical and link layer, EN 13757-3 application layer) for the remote reading of gas or electricity meters. M-Bus is also usable for other types of consumption meters. The M-Bus interface is made for communication on two wires, making it very cost effective. A radio variant of M-Bus (Wireless M-Bus) is also specified in EN 13757-4.[…]“

            Source: Wikipedia


"Universal Serial Bus (USB) is an industry standard developed in the mid-1990s that defines the cables, connectors and communications protocols used in a bus for connection, communication, and power supply between computers and electronic devices. [...]" 

            Source: Wikipedia


"Radio is the radiation (wireless transmission) of electromagnetic signals through the atmosphere or free space. Information [...] is carried by systematically changing (modulating) some property of the radiated waves, such as their amplitude, frequency, phase, or pulse width."


The process of risk-based testing according to Linear Q™ starts by identifying, capturing and weighting requirements according to their priority. During the test case design phase, all attributes and dependencies that have an impact on test requirements are identified.

Achieved / generated value:

Following value was achieved:

  • measurable, high quality
  • Measured technical / functional coverage of 92%
  • Optimal trade-off of financial measures taken vs residual risk. Identified and measured residual risk at 10% including mistakes made.
  • Minimal number of required and methodically devised test cases, resulting in a pronounced cost efficiency.
  • Traceability of tests according to predetermined standards.
  • high level of documentation, ensuring that technical know how of tests are retained and preserved, thus providing a high level of auditing security.