Osek turbo
Upcoming SlideShare
Loading in...5

Like this? Share it with your network

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads


Total Views
On Slideshare
From Embeds
Number of Embeds



Embeds 290

http://pradeepkumar.org 176
http://www.pradeepkumar.org 92
http://www.tcbin.com 19
http://www.techcognize.com 1
http://pradeepkumarorg.blogspot.in 1
https://www.linkedin.com 1

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

    No notes for slide


    SCS, VIT University
    OSEK/VDXAReal Time Operating System
  • 2. Automotive Software Standards
    Introduction to OSEK/VDX
    OSEK/VDX Characteristics and Specification
    OSEK Architecture
    Conformance Classes (CC)
    Tasks Concepts
    Interrupts Processing
    Scheduling Policies
    Other OS Services
    Topics for discussion
  • 3. Automotive Software Standard
    • 4. Automotive Open System Architecture
    • 5. OSEK/VDX
    • 6. Open systems and the corresponding interfaces for automotive electronics / Vehicle Distributed eXecutive
    • 7. MISRA C
    • 8. Motor Industries Software Reliability Association
  • OSEK/VDX Characteristics
    • Scalability
    • 9. Used for wide range of control units for 8bit to 32 bit controllers
    • 10. Uses four conformance classes that specifies the main features
    • 11. Portability of software
    • 12. ISO/ANSI-C Standard interface between the application and the OS
    • 13. Configurability
    • 14. Standard configurable information is provided with the help of OIL (OSEK Implementation Language)
    • 15. Statically allocated OS
    • 16. To simplify, The OS, application tasks, resources and services are requested to define at the compile time
  • OSEK/VDX Specification
    • Three Processing Levels
    • 17. Interrupt Level
    • 18. A logical level for OS Activities
    • 19. Task Level
    The interrupt levels are assigned higher priorities than the task levels
    • In addition
    • 20. OS Services provided for task management, event management, resource, counter, alarm and error treatment
  • OSEK/VDX Specification
  • 21. OSEK/VDX Architecture
  • 22. OSEK COM
    • The OSEK standard comprises also an agreement on interfaces and protocols for in-vehicle communication called OSEK COM
    • 23. An Interaction layer which provides communication services for the transfer of application messages.
    • 24. A Network layer which provides services for the unacknowledged and segmented transfer of application messages
    • 25. A Data link layer interface which provides services for the unacknowledged transfer of individual data packets over a network to the layers above.
    • Very often electronic control units (ECU) made by different manufacturers are networked within vehicles by serial data communication links.
    • 26. For this reason the standard propose a Network Management system (OSEK NM) that provides standardized features which ensure the functionality of inter-networking by interfaces.
  • OSEK/VDX Architecture
    • Traditional Fixed Priority Approach
    • 27. Each task in the system may be
    • 28. Basic Task (BT)
    • 29. Extended Task (ET)
    • 30. Each Task will be assigned a fixed Priority (assigned at compile time)
  • OSEK/VDX Architecture
    • Conformance Classes
    • 31. To provide support for different features and requirements of the application in terms of number of tasks, memory consumption, etc
    • 32. BCC1
    • 33. Only basic tasks limited to one activation request per task and one task per priority, while all tasks have different priorities.
    • 34. BCC2
    • 35. Like BCC1, plus more than one activation request per task and more than one task per priority.
    • 36. ECC1
    • 37. Like BCC1, plus extended tasks.
    • 38. ECC2
    • 39. Like ECC1, plus more than one task per priority and multiple requesting of task activation allowed for basic tasks.
  • Conformance Classes
  • 40. Tasks Concepts
    • Basic Task
    • 41. Basic tasks only release the processor, if
    • 42. they terminate
    • 43. the OSEK operating system switches to a higher-priority task, or interrupt occurs which cause the processor to switch to an interrupt service routine (ISR).
    • 44. Extended Tasks
    • 45. In contrast to basic tasks extended tasks are allowed to use the operating system call WaitEvent, which may result in a waiting state
    • 46. The waiting state allows the processor to be released and to be reassigned to a lower-priority task without the need to terminate the running extended task
    • 47. In view of the operating system, management of extended tasks is, in principle, more complex than management of basic tasks and requires more system resources
  • Tasks Concepts
  • 48. Tasks Concepts
    • Extended Tasks have four task states:
    • 49. Running
    • 50. Only one task can be in this state at any point in time
    • 51. Ready
    • 52. The scheduler decides which ready task is executed next
    • 53. Waiting
    • 54. A task cannot continue execution because it has to wait for at least one event
    • 55. Suspended
    • 56. The task is passive and can be activated
  • Interrupt Processing
    In particular, the standard provides two kind of ISR handlers:
    • ISR Category 1
    • 57. ISR does not use an OS Service.
    • 58. No OS calls from the handler
    • 59. The designer is free to write his own handler
    • 60. These are the faster highest priority Interrupt
    • 61. ISR Category 2
    • 62. ISR is handled by the OS
    • 63. So OS calls can be called from the handler
  • Events
    • Event Mechanism is provided only for Extended Tasks
    • 64. Each (ET) owns a set of events that can be triggered by other BT or ET or even ISR Category 2
    • 65. The behavior of an ET is to wait for an Asynchronous Event calling the OS Service WaitEvent()
    • 66. Events can be set only if the task is not in the suspended state
  • Scheduling Policy
    • Mixed Preemptive Scheduling
    • 67. Non Preemptive scheduling
  • Scheduling Policy
    • Mixed Preemptive Scheduling
    • 68. Since preemptiveness is a task attribute, preemptive and non-preemptive tasks can be mixed in the same application.
    • 69. The running task will influence the policy really used.
  • Other OS Services