https://embeddedcoffe.my.id/tags/rtos/Recent content in Rtos on Embedded CoffeHugoen-USMon, 10 Aug 2026 14:30:00 +0000https://embeddedcoffe.my.id/posts/stm32-freertos-task-scheduling/Mon, 10 Aug 2026 14:30:00 +0000https://embeddedcoffe.my.id/posts/stm32-freertos-task-scheduling/<p>When transitioning from a simple super-loop (<code>while(1)</code>) architecture to a Real-Time Operating System (RTOS), understanding the scheduler&rsquo;s behavior is vital for predictable and crash-free execution.</p> <p>In this article, we dissect how FreeRTOS manages task context switching on ARM Cortex-M4 cores (STM32F4/G4 series) and how to avoid classic concurrency pitfalls.</p> <h2 id="the-cortex-m-pendsv-exception">The Cortex-M PendSV Exception</h2> <p>FreeRTOS relies on the <strong>PendSV</strong> (Pended Service Call) exception to perform context switches safely. Unlike hardware ISRs that must execute with minimal latency, PendSV is configured with the lowest interrupt priority.</p>