EMBEDDED SYSTEM SOFTWARE AND RTOS BASICS DIAGRAMS

EMBEDDED SYSTEMS SOFTWARE TRAINING CENTER

1

Diversity of the Embedded Systems

The range of embedded systems is extremely diverse both in terms of its scale and nature.

There is currently no effective way of classifying the various systems.

Embedded device total cost

* It is also necessary to add in a time-to-market factor.

！ Today development costs have become a significant factor in mass-production.

Controls rice cookers to nuclear power plants

2

Case Example: Embedded system used in car

Provided by Toyota Motor Corporation 3

Software embedded in an equipment and in LSI

• DSP – Digital Signal Processor• LSI – Large Scale Integration

4

Embedded software size and deployment

Sales of embedded s/w is congruous with sales of large s/w systems, like MS Windows

5

The size of the respondents (the number of employees)

Compare this data with your company.

6

The size of the respondents (sales)

Compare this data with your company.

7

Breakdown of the total development cost in the operating department

The cost of software development accounts for 40% of total development costs.

8

Types of targeted processors

The 32 bits era

9

Programming languages

Mainstream isC language

10

Targeted OS

ITRON hasthe largest sector

11

Processing Order: Cooperative vs. Preemptive

Process B2Process B2

Process AProcess A

Process CProcess C

Process B1Process B1

Process DProcess D

Process A (low priority, cyclic)Process A (low priority, cyclic)

Process C (high priority, cyclic)Process C (high priority, cyclic)

Process B (low priority)Process B (low priority)

Process D (high priority)Process D (high priority)

OS

Preemptive MultitaskingCooperative Multitasking

Processes (tasks) are run in an infinite loop

If task takes too much time (B), need to divide it

No overhead occurs

Scheduling is performed by the OS Long task is suspended if needed Overhead: caused by OS internals

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References

1. Embedded systems: Christof Ebert, Jurgen Salecker, “Embedded Software-Technologies and Trends”

Steve Heath, “Embedded Systems Design - 2ed”

Michael Barr; Anthony J. Massa, “Programming embedded systems: with C and GNU development tools”

2. Scheduling: http://faculty.cs.tamu.edu/bettati/Courses/663/Fall-2001/Slides/sched_approaches.pdf http://faculty.cs.tamu.edu/bettati/Courses/663/Fall-2001/Slides/clock_driven.pdf http://faculty.cs.tamu.edu/bettati/Courses/663/Fall-2001/Slides/priority_driven.pdf

3. Synchronization http://www.isi.edu/~faber/cs402/notes/lecture6.html http://www.isi.edu/~faber/cs402/notes/lecture7.html

4. On-line library http://www.slac.stanford.edu/comp/unix/package/rtems/doc/rtems/index.html

5. QNX architecture http://filene.ru/second