為解決計算機外設種類的日益增加與有限的主板插槽和端口之間的矛盾,IBM、Inter、DEC、ComPaq、Microsoft、NEC和NorthTlecom等廠商于1994年底制定了一種新的PC外設接口標準——USB。USB具有傳輸速度快,支持熱插拔和即插即用,易于擴展,占用的系統資源少等優點。USB1.1支持兩種傳輸速率:1.5Mbps和12Mbps ,而USB2.0將速度提高了40倍(即480Mbps),能夠滿足高速外設的需要,但價格也隨之提高。
本課題重點介紹了USB總線的體系結構和特點,包括總線特征、信號環境、傳輸類型等;并針對傳統的PCI、ISA、EPP/ECP等接口的數據采集卡的不足,我們們提出了一種基于USB1.1接口技術和DSP(Digital signal processing 數字信號處理器)的數據采集卡的實現方案。設計并制作了基于USB接口的數據采集卡的硬件系統,編寫USB1.1接口芯片的固件程序。最后,為了實現主機軟件和數據采集卡之間的通信,編寫了數據采集卡的USB設備驅動程序。
基于課題的研究內容,本論文先對USB總線技術進行了介紹,然后以設計一種基于USB1.1接口技術的數據采集卡為例,詳細地介紹了USB的硬件設計、固件設計和驅動程序設計。在硬件設計部分,論文首先介紹了USB1.1接口芯片的性能和特點,然后給出了具體的硬件設計方案;固件設計是USB設計的重點;驅動程序開始部分先論述了驅動程序開發工具的選擇,然后介紹了本數據采集系統的USB設備驅動程序的設計。
關鍵詞 USB; 數據采集; USB1.1
ABSTRACT
In order to resolve the conflict between the increase of PC peripheral devices and the limited board slot and port, IBM, Intel,ComPaq, DEC, Microsoft, NEC and North Tlecom have developed a new interface standard of PC-- USB (Universial Serial Bus) in 1994. USB has the advantage of high speed, HotPlugIn, Plug and Play, easily to expand and engrossing less system resource, etc. USB1. 1 has two kinds of speed: 1.5Mbps and 12Mbps, but USB2.0 has the speed of 480Mbps, which can meet with the demands of high speed peripheral devices.
This subject discusses the architecture and feature of USB, including bus attributes, signal environment, data flow model, and so on. After that, it brings forward a design scheme of data acquisition card with USB1.1 interface and digital signal processing, which is based upon the defects of traditional industry bus, such as ISA, PCI. Then it designs and realizes the hardware system of the data acquisition card with the USB interface. At last, it programs the USB device driver of data acquisition card.
Base d on the subject, this paper introduces the USB bus technology at first and then shows the design of data acquisition system, which in cluds four segments: hardware design, firm ware design, device driver and application program. In driver program segment, the paper shows how to choose the driver develop tools and introduce the USB deviced river of this data acqusition card. At last, a summary will be presented as the end of the paper.