文档介绍：接口硬件作了详细的阐述。采用 PCI-1394 接口卡作为上位机接口,
设计专门的 1394 前端模块作为伺服控制模块的接口。随后,本文重点研究了 1394 OHCI 协议,尤其对协议中 DMA 相关的寄存器做了细致分析,并且阐述了应用于数控系统的 DMA 方式传输原理,即通过 RTX 提供的 API(应用程序接口)函数对 1394 芯片的寄存器进行直接的操作来实现数据的传输。之后,本文按照了“发送——接收”的传输模型,开发了 1394 DMA 方式数据传输的软件,细致阐述了整个传输过程的流程,并且给出了 RTX 提供的 API 函数的使用方法。在软件的设计过程中,按照软件工程的要求对开发的程序进行了模块化,提高了代码的效率,使程序结构更加清晰。最后,对实现上位机与 1394 前端模块间 DMA 方式数据传输的软件进行了测试,通过分析大量的测试数据验证了系统具有高可靠性和高实时性,足以满足高档数控系统的性能要求。
关键词:IEEE 1394 总线,数据传输,实时性,DMA
Implementation C System Real-unication by DMA Method Based on IEEE 1394 Bus
ABSTRACT
With the rapid development of Numerical Control technology, a high-C machine tool can meet the reqirements such as high-speed and high-precision machining, as well as multi-channal and multi-axis control. It is important to build a data transmission channal between NC and PC, in order to realize the excellent performance of a high-C machine tool.
The aim of C system designed in this thesis is to ensure that unication puter and servo unit can meet the requirements of real-time and reliability. The following schemes are
adopted in order to meet the requirements mentioned above:Firstly, IEEE
1394 bus is selected to connect puter and servo unit, because the application of the high-speed and high-performance numerical servo bus technology has e a major characteristic and trend in the development of the C system. IEEE 1394 bus which has a flexible framework and supports synchronous and asynchronous data transmission with the speed up to 400Mbps, hot-pluggable has e the best choice of high-speed servo bus. Secondly, Windows+RTX (Real Time Extension) which is selected as the operation system of puter provides the platform for the software of data transmission. Finally, asynchronous data transmission by DMA method is implemented based on Open Host Controller Interface (OHCI) protocol in order to improve the transmission speed further. Thus, the process of data transmission es as clear as possible, and it is beneficial to trace the status of data tra