ARM® Memory Protection Unit (MPU)

Both Cortex®-M3 and Cortex®-M4 MCU support an optional feature called the memory protection unit (MPU). The MPU is an optional component in the ARM® Cortex®-M4 microcontroller. The main purpose of using this MCU is to protect memory regions by defining different access permissions in privileged and unprivileged access levels for some embedded operating systems (OS). This chapter presents the initialization and configuration of the MPU, and discusses the detailed operational procedure of the setup and configuration of a MPU. A practical example MPU project is provided step by step to illustrate how to use these MPU registers to perform memory regions protection functions. The TivaWare^TM Peripheral Driver Library provides nine MPU-related API functions to configure, enable, set, and get required memory regions for the MPU. The MPU is tightly coupled to the Cortex®-M4 processor core and provides a means to establish access permissions on regions of memory.