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Automotive embedded systems part2 v1
- 1. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system AutomotiveEmbedded Systems part2 (OSEK/VDX) Operating System ENG.KEROLES SHENOUDA 1
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- 3. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system AUTOSAR AUTOSAR = AUTomotive Open System Architecture More informations on the site: http://www.autosar.org 3Will talk in details in the next parts. But Now I need to focus on the AUTOSAR OS
- 4. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system AUTOSAR AUTOSAR = AUTomotive Open System Architecture More informations on the site: http://www.autosar.org 4Will talk in details in the next parts. But Now I need to focus on the AUTOSAR OS Application layer: software components which implement ECU functions RTE: middleware which implements and access to the hardware resources for the application layer
- 5. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system AUTOSAR AUTOSAR = AUTomotive Open System Architecture More informations on the site: http://www.autosar.org 5Will talk in details in the next parts. But Now I need to focus on the AUTOSAR OS Services layer: AUTOSAR OS kernel, communication protocols, NVRAM access services, diagnostic services. ECU abstraction layer: high level access to on-board and off-board devices
- 6. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system AUTOSAR AUTOSAR = AUTomotive Open System Architecture More informations on the site: http://www.autosar.org 6Will talk in details in the next parts. But Now I need to focus on the AUTOSAR OS Micro-controller abstraction layer: low level access to on-board devices. Complex drivers: free slot in the architecture to implement special device drivers
- 7. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system AUTOSAROS AUTOSAR OS is the specification of an OS kernel for AUTOSAR architecture. It is based on OSEK/VDX OS : It adds new concepts: OS-Application, Schedule Table, Global Time, Software Counter. the main improvement is the addition of configurable mechanisms for error detection in the kernel (called “protection facilities”) This rectify the OSEK/VDX OS inability to support critical systems 7
- 8. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system AUTOSAROS AUTOSAR OS is the specification of an OS kernel for AUTOSAR architecture. It is based on OSEK/VDX OS : Software counters Schedule Tables Global time synchronization Stack monitoring OS Applications Protection mechanisms the main improvement is the addition of configurable mechanisms for error detection in the kernel (called “protection facilities”) This rectify the OSEK/VDX OS inability to support critical systems 8
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- 10. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system OSEK/VDXOverview OSEK : "Open System sand the Corresponding Interfaces for Automotive Electronics" VDX : Vehicle Distributed executive The OSEK API was designed by automotive suppliers. System specification (architecture, interfaces et behavior) for automotive electronic embedded systems (http://www.osek-vdx.org ) OSEK/VDX (OSEK Vehicle Distributed eXecutive) Operating System(OS) Communications(COM) Network Management(NM) 10
- 11. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system OSEKSpecifications OSEK OS serves as a basis for the controlled real- time execution of concurrent applications OSEK OIL OIL provides a possibility to configure an OSEK/VDX application inside a particular CPU OSEK COM / NM provides interfaces and protocols for the transfer of data within vehicle networks 11
- 12. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system Goals& Motivations High expenses coming from the development and/or port of operating system No interoperability of systems built by different providers Standardized interfacing features Utilization of the existing resources in the vehicle, enhance the performance of the overall system without requiring additional hardware. Basic software reusability, Application portability. 12Reusability Distributed functions
- 13. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system Whereis OSEK compared to other OS ? 13
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- 15. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system OSEK/VDXOS 15 Services of OSEK: • Task services • Synchronization services (events) • Mutual exclusion services (resources) • One-shot and periodical services (counters and alarms) • Interrupt management services • Communication services • System services and error management
- 16. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system OSEKOS + OIL Application Objects of an OSEK application are all defined when the application is designed Objects are static. i.e: there are no creation/deletion of tasks, resources, ...dynamically during the execution of the application. Data structures are used to store the properties of the objects and are defined statically when the application is built. A language has been defined (and standardized) to define the attributes of the objects in a simple way: OIL: OSEK Implementation Language The OIL syntax is a simple one: based on objects (tasks, resources, …) with a value for each attribute. Some attributes have sub-attributes. 16
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- 18. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system SoWe will make our labs on Trampoline, So What is Trampoline? 18
- 19. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system Whatis Trampoline? Trampoline is an open platform for small embedded systems with real-time constraints It is based on the OSEK/VDX OS and AUTOSAR OS standards So it is compatible with OSEK/VDX OS and AUTOSAR OS API. OSEK/VDX and Autosar os are static operating systems. That means the objects of the application, tasks, events, resources, . . . , cannot be created or deleted during the execution of the application. All objects are statically designed and instead of forcing the user to describe the application in C, a work that can be error prone, a specfic language is used, OIL or XML2. A compiler, goil, is used to translate the description in the equivalent C structures. goil performs verifications too. 19
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- 21. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system Tasksin OSEK Tasks are « active » elements of the application 2 categories of tasks exist in OSEK/VDX: 21 Basic tasks Extended tasks A basic task is a sequential C code that must terminate The task that are able to wait for an event are called Extended tasks
- 22. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system Basictask states 22 Basic tasks only release the processor, if • they terminate, • the OSEK operating system switches to a higher-priority task, or • an interrupt occurs which causes the processor to switch to an interrupt service routine (ISR). The state model of basic tasks is nearly identical to the extended tasks state model. The only exception is that basic tasks do not have a waiting state.
- 23. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system Statesand status transitions for basic tasks 23
- 24. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_systemExtendedtasks 24 Extended tasks have four task states:
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- 26. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system OSEKscheduling policy Scheduling is done dynamically during the execution of the application. Tasks have a fixed priority The priority of a task is given at design stage; The priority does not change (almost, taking and releasing resources may change the priority); No round-robin. If more than one task have the same priority, tasks are run one after the other. ie a task may not preempt a task having the same priority Tasks may be preemptable or not (almost) This property is defined at design stage. 26
- 27. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system Schedulingmodes “Full preemptive”: All tasks are preemptable. “Full non preemptive”: All tasks are non-preemptable “Mixed”: Each task may be configured as preemptable or non-preemptable It is the most flexible model. For instance, a very short task (in execution time) may be configured as non- preemptable because the context switch is longer than its execution. 27
- 28. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system ProcessingLevels 28 The OSEK operating system enables a controlled real-time execution of several processes which appear to run in parallel Entities which are competing for the CPU are: Interrupt service routines Tasks OSEK defines three processing levels: Interrupt level Logical level for scheduler Task level Priority rules: Interrupts have precedence over tasks
- 29. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system Fullpreemptive Full preemptive scheduling will put the running task into the ready state, as soon as a higher-priority task has got ready. The task context is saved so that the preempted task can be continued at the location where it was preempted. EX: task T2 with the lower priority does not delay the scheduling of task T1 with higher priority. 29
- 30. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system Fullnon preemptive the non preemptable section of a running task with lower priority delays the start of a task with higher priority up to the next point of rescheduling EX: task T2 with the lower priority delays task T1 with higher priority up to the next point of rescheduling (in this case termination of task T2). 30
- 31. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system Tasks’services 31 TASK(myTask) { //Task’s instructions … //Task_Service API }
- 32. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system TerminateTaskService StatusType TerminateTask(void); StatusType is an error code: E_OK: no error E_OS_RESOURCE: the task hold a resource E_OS_CALLEVEL: the service is called from an interrupt The service stops the calling task. The task goes from running state to suspended state. A task may not stop another task 32 TASK(myTask) { //Task’s instructions … TerminateTask(); }
- 33. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system ActivateTaskservice: StatusType ActivateTask(TaskType <TaskId>); The argument is the id of the task to activate. StatusType is an error code: E_OK: no error E_OS_ID: invalid TaskId (no task with such an id) E_OS_LIMIT: too many activations of the task This service puts the task <TaskId> in ready state If the activated task has a higher priority (preemptive), the calling task is put in the ready state. The new one goes in the running state. 33 TASK(myTask) { //Task’s instructions … ActivateTask(T2); ….. }
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- 37. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system ChainTaskservice StatusType ChainTask(TaskType <TaskId>); The argument is the id of the task to activate; StatusType is an error code: E_OK: No error E_OS_ID: invalid TaskId (no task with such an id) E_OS_LIMIT: too many activations of the task This service puts task <TaskId> in ready state, and the calling task in the suspended state. This service replaces TerminateTask for the calling task 37
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- 40. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system 40 •The requirement • Two Basic Tasks T1 And T2 • T1 (autosatart)will toggle led 0 • T2 Will toggle led 1 • T1(priority) > T2(priority) • Led0 @ PortA bin 4 • Led1 @ PortA pin 5 Led0 Led1
- 41. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system FirstWrite the oil File 41 We will learn the oil Parameters step by step Through labs
- 42. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system TheOil File PRIORITY : integer: the priority of the process. ACTIVATION : integer: the number of activation of a task. 1 for and extended task or an ISR. AUTOSTART: boolean : true if the process is an autostart task, false otherwise. 42
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- 45. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system 45 •The requirement • Two Basic Tasks T1 And T2 • T1 (autosatart)will toggle led 0 • T2 Will toggle led 1 • T1(priority) > T2(priority) • Led0 @ PortA bin 4 • Led1 @ PortA pin 5 Led0 Led1
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- 49. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system 49 •The requirement • Two Basic Tasks T1 And T2 • T1 (autosatart)will toggle led 0 • T2 Will toggle led 1 • T1(priority) < T2(priority) • Led0 @ PortA bin 4 • Led1 @ PortA pin 5 Led0 Led1
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- 54. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system Tasks’synchronization Synchronization of tasks: A task should be able to wait an external event (a verified condition). To implement this feature, OSEK uses events. Task’s model is modified to add a new state: waiting. The task that are able to wait for an event are called Extended tasks 54
- 55. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system Willgo #in_depth in the next session get Break 55
- 56. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system References Embedded Microcomputer Systems Real Time Interfacing Third Edition Jonathan W. Valvano University of Texas at Austin. MicroC/OS-II the real-time kernel second edition jean j.labrosse. RTOS Concepts http://www.embeddedcraft.org. OSEK/VDX Operating System Specification 2.2.3 AUTOSAR Layered Software Architecture The Trampoline Handbook release 2.0 Trampoline (OSEK/VDX OS) Test Implementation -Version 1.0, Florent PAVIN ; Jean-Luc BECHENNEC 56
- 57. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system References Trampoline:an open platform for (small) embedded systems based on OSEK/VDX and AUTOSAR http://trampoline.rts-software.org/ Jean-Luc Béchennec1;2, Sébastien Faucou1;3 1IRCCyN (Institute of Research in Communications and Cybernetics of Nantes) 2CNRS (National Center for Scientific Research) / 3University of Nantes 10th Libre Software Meeting 57
- 58. https://www.facebook.com/groups/embedded.system.KS/ Follow us Press here #LEARN_IN DEPTH #Be_professional_in embedded_system References Real Time Systems (RETSY) Jean-Luc Béchennec - Jean-Luc.Bechennec@irccyn.ec-nantes.fr Sébastien Faucou - Sebastien.Faucou@univ-nantes.fr jeudi 12 novembre 15 AUTOSAR Specification of Operating System V5.0.0 R4.0 Rev 3 OSEK OS Session Speaker Deepak V. M.S Ramaiah School of Advanced Studies - Bangalore 1 58
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