Mastering RTOS: Hands on FreeRTOS and STM32Fx with Debugging

Download and install STM32Qube IDE, choose a compatible version (1.19 or 1.18), and understand that QBMX code generator is separate in version 2.0, enabling bare metal programming.

Install STM32CubeIDE on Ubuntu by running the installation script, granting executable permissions with sudo chmod +x, executing the installer, accepting the license, and searching for ST to launch the app.

Download microcontroller datasheet and reference manuals from ST's site, then collect board documentation, including the product specification, user manuals, and schematics, from the development board page.

Create a workspace and download the FreeRTOS kernel version 202012 for GCC, exploring kernel sources. Review the MIT license and FreeRTOS-Plus components included.

Create a hello world FreeRTOS project on the STM32F407 discovery board using STM32CubeIDE, exploring task creation APIs and compiling, plus workspace setup and choosing a project type.

Add the FreeRTOS kernel source to an STM32 project manually by creating a ThirdParty folder, copying include and portable files, and selecting the cm4f gcc port, or via STM32Cube IDE.

Add include paths for the FreeRTOS kernel headers using the MCU GCC compiler. Resolve missing header errors and prepare adding FreeRTOSConfig.h for kernel customization.

Set timer 6 as the FreeRTOS time base to avoid conflicts with STM32Cube HAL, initialize timer 6 for 1 ms ticks, and configure NVIC to 4-bit preemption and 0-bit subpriority.

Learn to add the FreeRTOS kernel to an STM32 project via STM32CubeIDE's graphical interface, configure FreeRTOS v2, heap, time base, and re-entrant Newlib for multi-threaded apps.

Learn how to create a FreeRTOS task with xTaskCreate, pass parameters, assign a name and priority, manage stack depth via configSTACK_DEPTH_TYPE, and save a task handle.

Set FreeRTOS task priorities to resolve CPU contention, using 0 to configMAX_PRIORITIES-1 and noting RAM and context switch implications; practice creating two equal-priority tasks that print hello world messages.

Explore how FreeRTOS schedules tasks with pre-emptive and cooperative policies, including round-robin and priority-based methods, using the RTOS tick and configUSE_PREEMPTION to manage context switches, blocking, and yielding.

Learn how FreeRTOS dynamically allocates task TCBs and stacks from the heap, controlled by configTOTAL_HEAP_SIZE, and how kernel objects like semaphores and queues use the same heap.

Download and set up SEGGER SystemView trace tools to analyze FreeRTOS activities, including host SystemView software, target source files, SystemView user manual, and J-Link utilities.

Explore SEGGER SystemView, a toolkit that analyzes embedded software behavior by tracing FreeRTOS events, tasks, ISR timings, and idle time, using PC visualization and target code.

Segger SystemView real-time and single-shot recording modes for FreeRTOS, using J-Link or ST-Link, and how RTT transfers events to the host.

Analyze Segger trace of a two-task FreeRTOS example, showing SysTick interrupts, scheduler context switches, and Task-1 and Task-2 alternating execution, yielding 50% CPU load with no idle time.

Idle task is automatically created at the lowest priority to keep one task running and free memory from deleted tasks, while timer services task manages software timers when enabled.

Explore the FreeRTOS scheduler implementation, combining kernel code with architecture specific parts in port.c and portmacro.h for ARM Cortex Mx, including vPortSVCHandler, PendSVHandler, and SysTickHandler.

The lecture shows how vTaskStartScheduler initializes the FreeRTOS scheduler, configures SysTick for the tick rate, and starts the first task via SVC, with PendSV and SysTick handlers managing context switching.

Explore how SysTick timer implements the RTOS tick and increments xTickCount via configTICK_RATE_HZ. See how the tick ISR wakes sleeping tasks with vTaskDelay and triggers a context switch via PendSV.

The xPortStartScheduler function configures SysTick for a 1 ms RTOS tick by setting the SysTick load to 24999, enabling SysTick interrupts, and assigning the lowest priority (15) on ARM Cortex-M.

Monitor how the RTOS tick ISR SysTickHandler updates xTickCount, checks unblocked tasks, and requests a context switch via PendSV while masking interrupts briefly; context switching occurs in PendSV_Handler.