A microcontroller system, such as a system-on-a-chip integrated circuit, including a processor (e.g., a Von Neumann processor), memory, and a memory protection unit (MPU), where the MPU provides execute-only access rights for one or more protected areas of the memory. The MPU can allow instructions fetched from within a protected area to access data in the protected area while preventing instructions fetched from outside the protected area from accessing data in the protected area.