Design And Verificaton Of The MPU Module On The DW8051 Platform

As the integrated circuit develops rapidly, the security and stability of the chips draw more and more concern. Memory protection is a very important part of a chip's security. Embedded systems have been used very widely nowadays; they are used in many areas such as industry control systems, automotive electronics, and consumer electronics and so on. It can help to make sure the system runs stably and reliably if the memory protection function is added to the embedded system. Therefore, the research of the memory protection techniques is highly valuable. In the very commonly used ARM CPUs, there are memory management (MMU) which provides complex memory management and protection mechanism and memory protection unit(MPU) witch provides relatively simpler memory protection mechanism.The MPU this paper discussed is based on the DW8051 platform. The protection of access right of different region approach is used to supply hardware support for the protection of the system's ROM area. This hardware module cooperates efficiently with the code banking technique which is supported by the KEIL integrated develop environment to manage and protect the system's ROM area.This paper introduces the memory management and protection concepts first, and describes the functional division of the MPU and discusses the design of each of the functional modules in detail. The method to map the ROM space to the RAM space is proposed to solve the problem of how to program the ROM besides extending the ROM memory space. We chose the static region policy to work with the overlap region technique which controlled by region privilege. In this way, not only the hardware resource is saved but also the system's ROM space is managed efficiently. The software hardware co-verification and VMM methodology are introduced briefly and an optimized ROM space mapping method is proposed based on the code banking technique; with this method, less ROM space is wasted. With the verification environment constructed, the DW8051 system with MPU module included is verified by functional verification, FPGA verification, ASIC logic synthesis and formal verification. The verification results prove that the DW8051 system with MPU module can provide efficient memory protection for the ROM space.