以LEON开源SoC平台为基础,构建MELP声码器片上系统,给出实现过程中用到的一系列开源软、硬件开发组件。MELP算法是一种低比特率、高质量的语音编解码算法,面向移动设备和保密电话。选用LEON2做为SoC平台的处理器,MELP算法直接运行于LEON2处理器之上,计算密集型模块采用软硬件协同设计的思想,设计成隶属于总线的IP核。原型系统构建在Statix2-EP2S60开发板之上,采用CYGWIN作为工作站。同时给出传统NiosII处理器与LEON2的性能差异作为对比,这更预示着开源平台将成为未来SoC设计的一种新的选择。
In this paper,the authors' experiences in developing a System-on-a-Chip vocoder based on various open source components in both hardware and software parts are presented.The MELP vocoder oriented to mobile device and secure communication features low bit rate and high quality.LEON2 is chosen as the main processor,and the algorithm runs directly on LEON2 processor.The hardware/software co-design technology is adopted in the computing-intensive modules,and the computing-intensive parts of the algorithm are selected and designed as an AMBA compatible hardware core.The demonstration prototype is built up on the Stratix2 EP2S60 prototyping board using CYGWIN as the workstation.As compared with NiosII processor,LEON2 processor could achieve much better results.All this show that the development of SoC by using open source platform may be a new choice in the future.