https://hoanguyen.de/categories/rtos--architecture/Recent content in RTOS & Architecture on Hoa Nguyen — Embedded Software ArchitectHugoen-usSat, 25 Jul 2026 00:00:00 +0000https://hoanguyen.de/posts/microsd-active-object-qpc-usdhc1/Sat, 25 Jul 2026 00:00:00 +0000https://hoanguyen.de/posts/microsd-active-object-qpc-usdhc1/Building an SdCard active object on the i.MX RT1062: hardware card detect, the blocking-API problem that forces a worker task, and the coupled CD line that made detection fail unpredictably until I stopped trusting the interrupt.https://hoanguyen.de/posts/freertos-qpc-context-switch-cortex-m7/Sat, 25 Jul 2026 00:00:00 +0000https://hoanguyen.de/posts/freertos-qpc-context-switch-cortex-m7/One line at the end of an ISR wakes an active object in well under a microsecond — or a millisecond later if you leave it out. Here is the full path: hardware exception frame, PendSV, and where QP/C sits in it.