How does a Memory Protection Unit (MPU) work and how is it configured?

MPU provides memory protection without virtual memory, essential for safety and security in embedded systems. How it works: Defines memory regions with attributes (address, size, permissions). Checks all memory accesses against region rules. Generates fault exception on violation. ARM Cortex-M MPU: 8-16 configurable regions, size power of 2 (32B minimum). Attributes: XN (execute never), AP (access permissions), TEX/S/C/B (memory type, caching). Regions can overlap; highest number region wins. Configuration steps: Enable MPU, define region base address, set size and subregion disable bits, configure access permissions and memory attributes, enable region. Use cases: Separate task memory spaces in RTOS. Protect kernel from user tasks. Prevent stack overflow (guard region). Isolate security domains. Mark peripherals as device memory. RTOS integration: Context switch updates MPU regions per task. FreeRTOS-MPU provides this functionality.