Introduction to RTOS m5

Introduction to RTOS About SwiftACT • A Technology services startup company o Under establishment • Areas of specialties: o o Mobile telecommunication services development Embedded systems development • Types of services: o o o o Consultation Managed services Sourcing Training Amr Ali Abdel-Naby@2010 Introduction to RTOS About Me • Graduated 2004 o ECE, ASU: yrs distinction • 5+ years in embedded systems development o SDLC, Apps, MW, DD, Porting, • 3+ years in SW engineering o PSP, CMMI, Systematic reuse, • 3+ years in SW testing o IBM certified, ISTQB certified, Amr Ali Abdel-Naby@2010 Introduction to RTOS Copyright • Materials in this course is the property of Amr Ali Abdel-Naby • Reproduction or transmission of the materials in any manner without the copyright owner permission is a law violation Amr Ali Abdel-Naby@2010 Introduction to RTOS Outline • • • • • • Introduction Tasks Semaphores Message Queues Other Kernel Objects Other Kernel Services Amr Ali Abdel-Naby@2010 Introduction to RTOS Outline • • • • • • Introduction Tasks Semaphores Message Queues Other Kernel Objects Other Kernel Services Amr Ali Abdel-Naby@2010 Introduction to RTOS Other Kernel Objects • • • • Pipes Event registers Signals Condition variables Amr Ali Abdel-Naby@2010 Introduction to RTOS Pipe Definition • • • • Unidirectional data exchange facility A pipe descriptor/pipe end Data is unstructured byte stream FIFO data reading Amr Ali Abdel-Naby@2010 Introduction to RTOS Pipe == Message Queue? • Conceptually, yes o o Reader blocks when pipe is empty Writer blocks when pipe is full • Significant differences are: o o o o No multiple message storage Stream of unstructured bytes No data prioritization FIFO data flow Amr Ali Abdel-Naby@2010 Introduction to RTOS Pipe Data was read (more data remain) Data was read (more space for writing) Data was read (no data left) Pipe created (no data) Empty Not Empty Data was written Data was written (more space for writing) Amr Ali Abdel-Naby@2010 Introduction to RTOS Full Data was written (no more space for writing) Pipe Usages Task-to-task or ISR-to-task data transfer Asynchronous inter-task communication Amr Ali Abdel-Naby@ 2009 Real-Time Operating Systems Typical Pipe Operations • Pipe creation and deletion o o o Pipe Open Close • Pipe read and write o o Read Write • Pipe control o Control • Pipe select o Select Amr Ali Abdel-Naby@2010 Introduction to RTOS Event Register • = Group of binary flags • Tracks occurrence of specific events • A task can check events occurrence to control its execution o o Checking events: No wait, wait, wait with timeout Conditional check: AND, OR … • Another task or ISR can post events ISR Task Task Amr Ali Abdel-Naby@2010 Introduction to RTOS Event Register Usages • Unidirectional activity synchronization • • • Task send event X to task Task decide 2when to receive Task receive event X No source identification No data transmission Amr Ali Abdel-Naby@2010 Introduction to RTOS Typical Event Register Operations • Event register send and receive o o Send Receive Amr Ali Abdel-Naby@2010 Introduction to RTOS Signal • • • • = SW interrupt Generated by tasks and ISRs System and RTOS dependent When a signal arrives, the task is diverted from its normal execution path, and the corresponding signal routine is invoked ISR Task Task Amr Ali Abdel-Naby@2010 Introduction to RTOS Signal Usages • Asynchronous event notification • Extending hardware ISRs in task’s context Amr Ali Abdel-Naby@2010 Introduction to RTOS Typical Signal Operations • • • • • • Catch Release Send Ignore Block Unblock Amr Ali Abdel-Naby@2010 Introduction to RTOS Condition Variable • Enables tasks communication and identifying shared resources states • A condition variable itself is a shared resource o Protected by mutexes ISR Task Task Amr Ali Abdel-Naby@2010 Introduction to RTOS Condition Variable Usage • Resource state notification • Task 1: o Lock mutex  Examine shared resource  While (shared resource is Busy)  WAIT (condition variable)  Mark shared resource as Busy o Unlock mutex • Task 2: o Lock mutex  Mark shared resource as Free  SIGNAL (condition variable) o Unlock mutex Amr Ali Abdel-Naby@2010 Introduction to RTOS Typical Condition Variable Operations • • • • Create Wait Signal Broadcast Amr Ali Abdel-Naby@2010 Introduction to RTOS [...]... Abdel-Naby@2010 Introduction to RTOS Typical Event Register Operations • Event register send and receive o o Send Receive Amr Ali Abdel-Naby@2010 Introduction to RTOS Signal • • • • = SW interrupt Generated by tasks and ISRs System and RTOS dependent When a signal arrives, the task is diverted from its normal execution path, and the corresponding signal routine is invoked ISR Task Task Amr Ali Abdel-Naby@2010 Introduction. .. routine is invoked ISR Task Task Amr Ali Abdel-Naby@2010 Introduction to RTOS Signal Usages • Asynchronous event notification • Extending hardware ISRs in task’s context Amr Ali Abdel-Naby@2010 Introduction to RTOS Typical Signal Operations • • • • • • Catch Release Send Ignore Block Unblock Amr Ali Abdel-Naby@2010 Introduction to RTOS Condition Variable • Enables tasks communication and identifying... Abdel-Naby@2010 Introduction to RTOS Condition Variable Usage • Resource state notification • Task 1: o Lock mutex  Examine shared resource  While (shared resource is Busy)  WAIT (condition variable)  Mark shared resource as Busy o Unlock mutex • Task 2: o Lock mutex  Mark shared resource as Free  SIGNAL (condition variable) o Unlock mutex Amr Ali Abdel-Naby@2010 Introduction to RTOS Typical Condition... events • A task can check events occurrence to control its execution o o Checking events: No wait, wait, wait with timeout Conditional check: AND, OR … • Another task or ISR can post events ISR 1 Task Task Amr Ali Abdel-Naby@2010 Introduction to RTOS Event Register Usages • Unidirectional activity synchronization • • • Task 1 send event X to task Task decide 2when to receive Task 2 receive event X No source...Pipe Usages Task -to- task or ISR -to- task data transfer Asynchronous inter-task communication Amr Ali Abdel-Naby@ 2009 Real-Time Operating Systems Typical Pipe Operations • Pipe creation and deletion o o o Pipe Open Close • Pipe read and write o o Read Write • Pipe control o Control • Pipe select o Select Amr Ali Abdel-Naby@2010 Introduction to RTOS Event Register • = Group of binary... Free  SIGNAL (condition variable) o Unlock mutex Amr Ali Abdel-Naby@2010 Introduction to RTOS Typical Condition Variable Operations • • • • Create Wait Signal Broadcast Amr Ali Abdel-Naby@2010 Introduction to RTOS