Real-time programming applied to the FreeRTOS operating system

http://www.ac6-training.com/cours.php/cat_FSCA/ref_RT3/

First Day RTOS Introduction 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 Exercice :  Interrupt Management on Cortex-M4 Introduction to Real Time Base real time concepts The Real Time constraints Multi-task and real time Thread safe data structures Need for specific data structures Thread safe data structures Linked lists Circular lists FIFOs Stacks Data structures integrity proofs Assertions Pre and post-conditions Exercice :  Build a general purpose thread safe linked list Second Day Element of a real time system 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 Exercice :  Analyse a Context Switch Task Management The Task life-cycle Creating tasks Deleting tasks The Endless-loop pattern Task Priorities Assigning task priorities Changing task priorities The idle task Idle task hooks Timing Exercice :  Managing tasks 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 Exercice :  Write a simple, thread safe, buddy system memory manager Exercice :  Write a generic, multi-level, memory manager Exercice :  Enhance the memory manager for memory error detection Exercice :  Detect stack overflow Third Day 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 Exercice :  Synchronizing a task with another one through binary semaphores Exercice :  Synchronizing a task with another one through queues Resource Management Mutual Exclusion Spinlocks and interrupt masking Mutex or Semaphore Recursive or not recursive mutexes Priority inversion problem Priority inheritance (the automatic answer) Priority ceiling (the design centric answer) Mutual exclusion through FreeRTOS Mutexes and binary semaphores Deadlocks Priority inversion Priority inheritance Critical sections Critical sections Suspending (locking) the scheduler Gatekeeper tasks Exercice :  Implement mutual exclusion between two tasks Fourth Day Parallelism Problems Solution Parallel programming problems Uncontrolled parallel access Deadlocks Livelocks Starvation Exercice :  The producer-consumer problem, illustrating (and avoiding) concurrent access problems Exercice :  The philosophers dinner problem, illustrating (and avoiding) deadlock, livelock and starvation 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 Exercice :  Synchronize Interrupts with tasks Software Timer The Timer Daemon Task Timer Configuration One-shot / Auto-reload Timer Software Timer API Exercice :  Implement Soft Timers Trouble Shooting Checking for stack problems Common pitfalls 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 Exercice :  Implement protected memory regions