RT3	FreeRTOS Real Time Programming

Real-time programming applied to the FreeRTOS operating system

Objectives Get an overview on Cortex-M4 architecture Discover the concepts of real time multitasking Understand Real Time constraints Determinism Preemption Interrupts Understand the FreeRTOS architecture Discover the various FreeRTOS services and APIs Learn how to develop FreeRTOS applications Learn how to debug FreeRTOS applications

Course environment Convenient course material with space for taking notes Example code, labs and solutions A PC under Windows 7 for two trainees A ST STM32F4 (Cortex/M4) with System Workbench IDE

Prerequisites Familiarity with embedded C concepts and programming Basic knowledge of embedded processors

First Day Cortex-M resources used by RTOS Cortex-M Architecture Overview Two stacks pointers Different Running-modes and Privileged Levels MPU Overview Systick Timer Description Exception / Interrupt Mechanism Overview Interrut entry and return Overview SVC / PendSV / Systick Interrupt Presentation Developing with the IDE Exercise:  Interrupt Management on Cortex-M4 Element of a real time system Base real time concepts The Real Time constraints Multi-task and real time Tasks and Task Descriptors Content of the task descriptor List of task descriptors Context Switch Task Scheduling and Preemption Tick based or tickless scheduling Scheduling systems and schedulability proof Fixed priorities scheduling RMA and EDF scheduling Scheduling through FReeRTOS Deterministic preemptive scheduling Scheduling strategies Cooperative scheduling Hybrid scheduling Exercise:  Analyse a Context Switch Task Management Creating Tasks Task Priorities Task States The idle task Delays Changing Task Priority Deleting Tasks Suspending Tasks Kernel Structures Thread Local Storage Kernel Interrupts on Cortex-M4 Scheduling Traces Visual trace diagnostics using Tracealyzer Exercise:  Task Management Exercise:  Periodic Tasks Exercise:  Task Statistics Second Day FreeRTOS Memory Management FreeRTOS Memory Managers Out of Memory management Stack Overflow Management Exercise:  Check stack usage in existing programs Resource Management Mutual exclusion through FreeRTOS Critical sections (interrupt masking) Suspending (locking) the scheduler Mutexes Mutexes concepts Mutex or Semaphore Recursive or not recursive mutexes Priority inversion problem Priority inheritance (the automatic answer) Priority ceiling (the design centric answer) Gatekeeper tasks Exercise:  Implement mutual exclusion between tasks Synchronization Primitives Introduction Waiting and waking up tasks Semaphores Events Mailboxes Binary Semaphores through FreeRTOS Give a Binary Semaphore Take a binary Semaphore Queue Management through FreeRTOS Creation Sending on a queue Receiving from a queue Data management Sending compound types Transfering large data

Event groups Task Notifications Stream Buffers and Message Buffers Exercise:  Synchronizing a task with another one through binary semaphores Exercise:  Synchronizing a task with another one through queues Exercise:  Task Notifications Exercise:  Properly use stream Buffers Exercise:  Message Buffers Parallelism Problems Solution Parallel programming problems Uncontrolled parallel access Deadlocks Livelocks Starvation Exercise:  The producer-consumer problem, illustrating (and avoiding) concurrent access problems Exercise:  The philosophers dinner problem, illustrating (and avoiding) deadlock, livelock and starvation Third Day Interrupt Management Need for interrupts in a real time system Software Interrupt Time Interrupts Device Interrupts Level or Edge interrupts Hardware and Software acknowledge Interrupt vectoring Interrupts and scheduling Deferred interrupt processing through FreeRTOS Tasks with interrupt synchronization Using semaphores within an ISR Counting semaphores Using queues within an ISR FreeRTOS interrupt processing Writing ISRs in C Interrupt safe functions Interrupt nesting Exercise:  Synchronize Interrupts with tasks Software Timer The Timer Daemon Task Timer Configuration One-shot / Auto-reload Timer Software Timer API Deferred interrupt handling Exercise:  Implement Soft Timers FreeRTOS-MPU The Cortex/M MPU User and privileged modes Access permissions Defining MPU regions Overlapping regions Predefined regions Programmer-defined regions Needed linker configuration Practical usage tips Exercise:  Implement protected memory regions appendixes Data structures Need for specific data structures Data structures Linked lists Circular lists FIFOs Stacks Data structures integrity proofs Assertions Pre and post-conditions Thread safety Exercise:  Build a general purpose linked list Memory Management Memory management algorithms Buddy System Best fit / First Fit Pools Management FreeRTOS-provided memory allocation schemes Allocate-only scheme Best-fit without coalescing Thread-safe default malloc Checking remaining free memory Adding an application-specific memory allocator Memory management errors Stack monitoring Exercise:  Write a simple, thread safe, buddy system memory manager Exercise:  Write a generic, multi-level, memory manager Exercise:  Enhance the memory manager for memory error detection

 

Duration	Cost	Calendar
3 days	2180 € HT
Last update: 21 April 2021
This course, designed for face-to-face delivery, can be provided either in our Paris training center or, worldwide, on your premises. Scheduled classes are confirmed as soon as there is a confirmed booking.
A version tailored for live online delivery is available under reference oRT3 - Real Time Programming with FreeRTOS
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