基于Windows CE的嵌入式開發(fā)研究
Research of Embedded Development Based on Windows CE
【摘要】 近年來基于嵌入式系統(tǒng)的數(shù)字化產(chǎn)品在全球范圍內(nèi)得到了突飛猛進(jìn)的發(fā)展，嵌入式技術(shù)已成為一個(gè)研究熱點(diǎn)和消費(fèi)熱點(diǎn)。而Windows CE由于它的多任務(wù)、實(shí)時(shí)性、模塊化、強(qiáng)大的通信能力等特點(diǎn)，在嵌入式系統(tǒng)的諸多領(lǐng)域都有了廣泛的應(yīng)用。本文首先探討了嵌入式系統(tǒng)的特點(diǎn)，分類，前景，然后對(duì)各種嵌入式操作系統(tǒng)和Windows CE的特點(diǎn)及開發(fā)工具進(jìn)行分析比較，接著介紹一個(gè)我們?cè)贛icrosoft Windows CE 5.0環(huán)境下基于eBoxII開發(fā)的智能家居安防保全系統(tǒng)eDog。eDog 可以通過攝像頭將采集到的實(shí)時(shí)視頻圖像進(jìn)行運(yùn)動(dòng)檢測(cè)，當(dāng)發(fā)現(xiàn)有運(yùn)動(dòng)產(chǎn)生時(shí)，通過撥打電話等多種方式自動(dòng)向用戶發(fā)出警報(bào)，同時(shí)將實(shí)時(shí)捕獲的圖像上傳到ftp 服務(wù)器。文章的最后詳細(xì)闡述了eDog的圖像采集模塊，運(yùn)動(dòng)圖像檢測(cè)模塊，圖像壓縮模塊，F(xiàn)TP上傳模塊的實(shí)現(xiàn)過程，并對(duì)我們所提出的運(yùn)動(dòng)檢測(cè)算法，視頻捕捉算法等做了詳細(xì)的說明。
There are many different (and often confusing) terms associated
with clock-based devices. This application note attempts
to clarify these terms, and hence serves as a comprehensive
reference on clock terminology. This application note can be
divided into two sections. The first section describes and distinguishes
between various clock sources available today.
The second section defines and distinguishes between various
parameters used to describe clocks. This section also provides methods of measuring some of these parameters.
Jitter is extremely important in systems using PLL-based
clock drivers. The effects of jitter range from not having any
effect on system operation to rendering the system completely
non-functional. This application note provides the reader
with a clear understanding of jitter in high-speed systems. It
introduces the reader to various kinds of jitter in high-speed
systems, their causes and their effects, and methods of reducing
jitter. This application note will concentrate on jitter in PLL-based frequency synthesizers.
Cypress Semiconductor makes a variety of PLL-based clock
generators. This application note provides a set of recommendations
to optimize usage of Cypress clock devices in a
system. The application note begins with recommended termination
techniques for clock generators. Subsequently, power
supply filtering and bypassing is discussed. Finally, the application
note provides some recommendations on board
layout.
