摘要
IEEE1394作为一种高速串行通信标准，不仅可以实现高传输速率，还具有带宽容量高，热插拔和总线动态配置等优点，特别适合于高速计算机外设(如扫描仪、消费类视听设备等)以及军用的实时信息传输(如战地通信，导航等)。
本文将1394总线技术用于VXI总线系统，开发了一种VXI外接式控制机—1394-VXI零槽资源管理器，通过1394接口实现了PC机与VXI仪器模块之间的数据传输，从而提高了VXI测试系统的性能，降低了成本。
1394-VXI转换器是实现IEEE1394总线与VXI总线协议交互的VXI零槽资源管理器模块。从1394-VXI转换器的功能出发，在电子科技大学CAT实验室成功开发GPIB-VXI转换器的基础上，采用MC68030作为系统处理器，VXI总线与本地总线之间的转换通过VXIbus接口控制电路实现；本地总线与1394总线之间的转换通过1394链路层和物理层接口实现；VXIbus地址译码控制电路提供本地存储器映象译码和VXIbus存储器映象译码，并与VXIbus接口控制电路相互配合，共同实现全面的VXIbus主者／从者接口功能；采用CPLD等可编程电路技术，实现了1394-VXI转换器地址译码，以及模块识别、10MHz时钟发生器和TTL触发电路等VXIbus系统所需的仪器公用总线。在1394 OHCI寄存器映射机制和DMA传输机制的基础上，采用1394异步传输方式和公平仲裁协议，以WinDriVeT为开发工具进行1394 OHCI程序开发，实现了1394总线的一系列总线操作功能。
本文详细介绍了1394串行总线和1394开放式主机接口的相关协议，重点讨论了1394-VXI零槽资源管理器的硬件设计和1394 OHCI程序设计。其中硬件设计主要包括VXI接口控制电路、1394接口电路、地址译码控制电路、模块识别电路、TTL触发电路等；1394OHCI程序设计包括总线配置检测、物理层状态传送、异步数据包的发送和接收的实现。本文同时也提出了作者在软硬件调试过程中的一些体会和理解。
As a high-speed serial bus specification , IEEE1394 not only realizes high transfer rates , but also has many benefits such as high bandwidth capacity , hot plugging and bus dynamic configuration , especially suits for high-speed computer peripherals such as scanners , and comsumer audio-video electronics , and military real time information transfer field such as strategic communication , navigation .
Using IEEE 1394 for VXI control , the paper developed 1394-VXI Slot 0 Resource Manager , data transfer between computer and VXI instrument module is realized by 1394 interface ,'so improved the VXI measure system performance and lowered it's cost.
1394-VXI converter is the Slot 0 Resource Manager module which realizes the interface between IEEE 13 94 bus and VXIbus . According to the function of the 1394-VXI converter , on the base of CAT Lab. UEST's the successful development of GPIB-VXI converter , the project use MC68030 as system processor , the transfer between VXIbus and local bus is realized by VIC ; the transfer between local bus and 1394bus is realized by 1394 link layer and physical layer ; VAC provides local memory and VXIbus memory mapping decode , and realizes the maste/slave interface fuction of VXIbus with VIC . Address decoding , module identification and TTLtrigger is realized by programmable circuit technology such as CPLD . On the base of 1394 OHCI register mapping and DMA engines , using 1394 asynchronous data transfer and fairness arbitration protocol , 1394bus operation fuction is realized by 1394 OHCI program developed with WinDriver .
The paper introduced correlative protocol in IEEE 1394 and 1394 OHCI in detail, and emphatically discussed the hardware design and 1394 OHCI program design of the 1394-VXI converter. The hardware include VXI interface controller circuit ,1394 interface circuit, Address coding circuit, MODID circuit and TTLtrigger circuit etc . 1394 OHCI program realized the test of 1394bus configuration , the status transfer of physical layer , the transmission and reception of 1394 asynchronous packets . And some idea and experience developed by the author in the course of circuit and
program debugging are discussed .
引文
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