Books on programming embedded systems

I'm looking for a good text an programming embedded systems (for example an automotive ECU) but I can't find any that suits the bill. I was hoping to suggest something to students that avoids the trial and error learning methodology I had to endure.

A quick search on Amazon shows some which could be relevant:

• Programming Embedded Systems: With C and GNU Development Tools by Michael Barr and Anthony Massa
• An Embedded Software Primer by David E. Simon
• Embedded C by Michael J Pont
• Embedded Software Development with C by Kai Qian, David Den Haring and Li Cao

Especially the latter sounds interesting since I like the software architecture book from the same author.

I was thinking of writing a book myself on the subject. But it would mostly haven been a collection of data one can find on the internet with some detective work. Subjects to include would be:

• Introduction to C, since embedded systems are programmed in C. Period....
  I like K&R, but you can choose any book that suits the bill.
• Good coding practices in C, for example MISRA C rules.
  Read some example of MISRA C-rules here, here and here.
• RTOS basics, since this is what is used on most embedded systems.
  Read chapter 1 in the User & reference manual of rt:kernel from rt:labs for a good introduction. But personally I prefer the "run-to-completion" type of tasks which don't wait for external events for predictability.
• Interrupts, stacks, and memory handling - ISR, RAM, NVRAM, ROM, Flash and every other acronym you can think of...
• Development environments, and compilers for embedded development
  My experience is that this is pretty much decided by the OS you are using. I have experienced very mysterious bugs just by not having the correct compiler version, so I can' imagine what could happen when having a compiler from a different vendor... IAR graciously provides all of their manuals free of charge and their IDE and compilers on 30-day on a 30-day free trial.
• Various hardware on a typical embedded controller - Details on how to access hardware with code examples.
  You can see examples of typical hardware devices in the Freescale MC9S12XS256 Reference Manual, a typical automotive processor, especially chapter 10-19. Mind you that this manual is 738 pages long, so it's pedagogical value is limited.
• Debugging - Too much to cover for this blog post. This is the real dark arts...
• Architecture of embedded systems
  Almost all embedded systems are layered, but why? And how do you know which layers to have in your system? And how do you identify the tasks you should have when schedule the system?

Competitiveness from structuring of AUTOSAR applications

AUTOSAR 4.0 was released some time ago, and in certain areas it was a major update compared to version 3.1 of the standard. Besides the changes to the Basic Software one of the things I think may have a great impact when it comes to sourcing software from suppliers are the results from the 10.x work packages that deals with application interfaces (i.e. interfaces of the software components above the RTE).

In my mind structuring the applications and standardising their interfaces pretty much defined what quality attributes ("-ilities") the software would have, especially when it comes to "Evolution qualities, such as testability, maintainability, extensibility and scalability, which are embodied in the static structure of the software system" to quote wikipedia. So with the OEM-supplier relationships that most vehicle manufacturers have and with the static structure standardised by AUTOSAR it would be almost impossible to compete with the "-ilities above. So how does one use AUTOSAR and "cooperate on standards, compete on implementation"?

I got the answer in a paper by Simon Fürst et al. presented at 14th International VDI Congress Electronic Systems for Vehicles 2009 in Baden-Baden.

"In general, applications are the competitive edge of an ECU. AUTOSAR is not going to standardize the functional internal behavior of an application (e.g. algorithms, optimization) but the content exchanged between applications. This clarifies the exchange of applications between the automotive community, from OEM to suppliers as well as supplier to supplier and so forth."

So competitiveness is "only" achieved by algorithm optimisation? A typical control engineer's viewpoint and not a software engineer's? This means that an OEM can only distinguish itself from the competitors by run-time qualities and not by qualities such as evolvability or testability?

Do I even need to say that this is my personal opinion based on the teaching I do in software architecture and does not necessarily reflect my colleagues' opinions or the company I work for.

Blogs

I follow two "professional" blogs:

• Heartbeat Development by a former colleague of mine, Johan Segertoft
• SEI Architecture Technology User Network Blog

The latter had in a recent post some links to other blogs which also deals with architecture.

ICSE 2011

The International Conference of Software Enginering is on Hawaii in 2011. Deadline for the main research track is Friday 20 August 2010. Time to hurry if I want to submit something...

Swedsoft meeting

Last week I attended a meeting between DICE and ABB with additional participants from Volvo Cars and Ericsson as well as some from academia. The meeting was arranged by Swedsoft.

I know nothing of the game industry so it was especially interesting to listen to the presenters from DICE, who all worked with the development of their game engine Frostbite. Some things were of particular interest:

• There is a fairly strong architecture for the Frostbite engine. Both for the runtime architecture (client-server) and even more important for the development architecture where the runtime architecture is just a "small" part besides e.g. the FrostEd editor for game objects and the build database(s).
  
• They use extensive knowledge about the game (domain knowledge) to minimise necessary information sent to/from the server and the clients (the latter being the software you buy at a gaming store and run on your Xbox360/PS3/PC).
• The run-time architecture uses parallel processing in multiple cores and distributes "jobs" between the cores dynamically.
  
• They use continuous builds, i.e. as soon as a programmer checks in new code it is built into a working program. This for the game developers always to have something to run.
• They only do positive testing, e.g. the program shall have this feature. No test on the program shall not...
• The Frostbite team consists of 19 developers and they update and maintain 1.5 MLOC for all 3 platforms (Xbox 360, PS3 and Windows). It is like we would maintain the entire in-vehicle software with 20 people.

I hope I didn't misunderstood anything...

Lindholmen Software Development Day 2010

Lindholmen Software Development Day is a yearly free get-together for local "software developers, managers, project managers and business developers" here at the north river shore in Göteborg. The theme for this year is

• Perspectives on and analyses of the changing market situation
• Software development philosophies supporting the changed situation
• Discipline Integration challenges and solutions, e.g., in H/W-S/W codesign
• Processes, Methods or tools to improve speed, efficiency, or quality
• Experience reports from new ways of working

I was asked by some people at Volvo Cars to present something relevant to us, and after some thought the topic of my talk would be "The future of automotive software engineering". Not pretentious at all...
Here is the outline I proposed. Any acceptance notification will come in August.

• General briefing on current and future trends in automotive software engineering
• Exponential increase in size, complexity, innovations, …
• Cycle times are dictated by what?
• Industry-wide ways to cope
• Standardisation
• Model-based development
• Architecture
• Soft issues
• Knowledge and maturity in the industry
• How to earn money?
• Some examples (from Sweden)

Concurrent architecture

To continue my thoughts about the programming language Erlang and especially how an architecture for a system implemented in Erlang would look like...

Joe Armstrong's PhD Thesis provides a very good understanding of the basic principles of Erlang. I think that some of the mechanism in the language makes several pattens in Pattern-Oriented Software Architecture Volume 2: Patterns for Concurrent and Networked Objects unnecessary.

I think it would be quite useful to describe the architecture in views. I think the "standard" 4+1 views could be used quite easy for a system implemented in Erlang as well.
However it may not be the logical view that the other views are derived from, rather I would think that the process view would be the basic view. Kruchten has an underlying assumption that the logical view is object-oriented. This is obviously not relevant for a system implemented in Erlang so a different notion of the logical view is necessary.

Joe Armstrong strongly suggest a hierarchy of processes. A problem domain model could be a good way to identify the top-level processes, e.g. the PDM classes could be the initial processes and the asynchronous interaction will be implemented as messages, since reality is asynchronous. I need to try this in practice though...