基于NIOS的绝对光栅编解码系统设计∗

摘要

为了实现绝对光栅尺的快速解码,提高绝对光栅解码的实时性,建立了片上Nios绝对光栅编解码系统。首先,使用Verilog hdl语言编写了光栅编码采集的前端CCD和AD驱动。接着,将转换后的数据送到后端,以EP2 C5 T144 C8为核心处理器的FPGA上的硬件加速模块,获得光栅条纹编码信息。然后,利用sopc技术,在实现Avalon数据接口ip核的基础上,搭建绝对光栅编码采集和处理平台,最后,在NIOS II IDE软件开发环境中,编写生成伪随机码绝对位置查询数据库和解码程序。实验结果表明：此编解码系统,在解码速度为2000帧/s条件下,精度为7μm,基本解决面阵做采集帧速不够的问题,并有较好的实时性,有效地降低了开发成本,为绝对光栅的开发提供了一个新的途径。%In order to realize the fast decoding absolute grating ruler, improve the real-time absolute grating decode, we established an on-chip Nios absolute grating encoding and decoding system. First of all, by u-sing Verilog HDL language ,we encoding CCD and AD driver which acquisite front-end grating. Then, we take the converted data to the backend where taking the EP2C5T144C8 FPGA as the core processor of hard-ware acceleration module, we obtain grating stripe code information. Then, using the SOPC technology, based on the realization of Avalon data interface IP core,we build absolute grating code acquisition and pro-cessing platform, finally, in the NIOS II IDE software development environment, we write programs which can generate the database of the pseudorandom code absolute position to query and decode. The experimen-tal results show that:This codec system get the accuracy of the 7μm in the decoding speed of 2000 frame/s conditions, basically solve the problem that the frame speed is inadequate by taking the plane array as the front-end acquisition, and has good real-time performance, effectively reduce the cost of development, pro-vides a new way for the development of absolute grating.