基于MCU的Flash预取加速控制器设计与实现

Design and Implementation for Fetching-Accelerating Flash Controller Based on MCU

为了解决低成本低功耗微处理器(Micro Control Unit,MCU)中嵌入式Flash读取速度的问题,基于预取和缓存原理,采用位宽扩展技术和改进预取技术相结合的方式,设计了具有预取加速功能的Flash控制器。实现Flash特定接口协议与高级高性能总线(Advanced High-performance Bus,AHB)协议的转换,提高处理器取值效率,提升系统性能。设计了完善的读写保护机制,以保护用户程序。同时搭建片上系统(System on Chip,So C)仿真实验平台验证设计的正确性,实验结果表明,本设计最多提高了16.3%的取指效率,并在实际样片中得以验证。

A fetching-accelerating flash controller,was designed in this paper for the sake of solving fetching speed problems of a low-cost and low-power MCU.Based on the mechanisms of fetching and cache,a method combining bitwise-expanding and promoted-fetching techniques was adopted.This Flash controller accomplished the conversion between Flash interface and AHB protocols,while improving the system performance and fetching efficiency.Furthermore,an explicit protection mechanism was proposed to protect the use code.What'smore,an SoCsimulation experiment platformwas established to confirmthe correctness of the design.The simulation results showthat the fetching performance was improved 16.3%at most.Finally,the design has been confirmed in an example wafer.