Design And Realization Of Hardware Abstract Layer In Monitoring Platform For μC/OS-Ⅱ System

With the wide applications of embedded system, people always focus on the problem that how to quickly build the platform in the story of embedded discipline, in the face of varied and changeable hardware. To solve this problem, the concept of a hardware abstract layer(HAL) emerges at this historic moment, many embedded systems have also introduced the hardware abstract layer, in order to isolate the operating system and hardware, and the software almost do not have to make any changes when hardware changes, thus the system enhances its portability.μC/OS-Ⅱ has been widely used for its excellent real time and stability in the industrial field. However, due to it’s a bare OS, videlicet, the idea of HAL is not imposed on the kernel, which seriously influence its portability. To solve this problem, the main objective of this project designs and implements the HAL for the upper operating system μC/OS-II and drivers to provide a unified interface, combined with the specific hardware platform.The HAL built for μC/OS-Ⅱ in this paper includes:boot loader, device management, interrupt management, timer management, memory management. The boot loader module brings the system to a suitable location; and the device management uses a virtual bus separating devices and drivers, viz, insulating the owner of the resource from actors; Interrupt management is divided into a critical part and a delayed part with hierarchical thinking. The critical part will be processed preferentially, which can meet the need of real-time performance, And the delayed part achieves deferred processing mechanism, using the priority dual task; Timer module designs several commonly used interface to complete all operations about timer; At the last, the memory management mainly uses the mirror mapping method to convert virtual address into the physical address.Finally, μC/OS-II system runs on the ARM architecture with hardware abstraction layer, which builds an industrial high-voltage circuit breaker monitoring platform. After the real-time and stability test, the results show that μC/OS-Ⅱ with HAL improves μC/OS-Ⅱ’s transplantation, and the same time, remains μC/OS-Ⅱ’s real time and stability basically unchanged.