【正文】 遼寧科技大學(xué)信息技術(shù)學(xué)院 1 1 基于 AVR 單片機(jī)的通訊系統(tǒng)設(shè)計(jì) 摘 要 在當(dāng)前社會(huì)，通信技術(shù)已經(jīng)深入到各行各業(yè)中 。 在本次系統(tǒng)設(shè)計(jì)中，將通信技術(shù)與單片機(jī)技術(shù)結(jié)合，完成了一個(gè)電壓信號(hào)采集及通信過程。系統(tǒng)設(shè)計(jì)過程中，了解 通信技術(shù)中的相關(guān)通信方式及協(xié)議，用 AVR單片機(jī)完成系統(tǒng)功能，分別完成硬件設(shè)計(jì)、軟件設(shè)計(jì)及系統(tǒng)測試工作，達(dá)到對(duì)整個(gè)通信系統(tǒng)的控制。 本文 以 ATMEGA8 單片機(jī)為控制 核 心，利 用直流電壓信號(hào)模擬輸入信號(hào)，采集輸入信號(hào)，將采集到的數(shù)據(jù)經(jīng)數(shù)字信號(hào)處理后傳給上位機(jī)分析并保存。 工作過程 ： 單片機(jī)初始化所用到的功能模塊的控制字，等待上 位機(jī)的開始采集命令。 接收到上位機(jī)的命令后，從 PC0(ADC0)端口采集電壓信號(hào)，完成模數(shù)轉(zhuǎn)換； 讀取轉(zhuǎn)換后的數(shù)據(jù)，根據(jù) A/D 轉(zhuǎn)換器的輸入 /輸出關(guān)系確定實(shí)際的電壓信號(hào)值； 將電壓信號(hào)值保留一位小數(shù)，進(jìn)行 BCD 編碼后，通過異步通信方式發(fā)送給上位機(jī)； 上位機(jī)通過 GUI 界面將數(shù)據(jù)實(shí)時(shí)顯示出來，并可人為的保存采集的結(jié)果； 關(guān)鍵字 ： AVR； ATMEGA8；電壓采集；通信； MAX232 遼寧科技大學(xué)信息技術(shù)學(xué)院 2 2 Abstract In moden time, technology has been perated into a large number of industry， under this environment。 It is useful to design the system which bine municationtechnology with SCM technology to achieve a process of collect voltage and munication。 During the period of system designing， what is munication pattern and protocol must be known， on this basis， using AVR SCM to finish the function what we need in this system， which include circuit design、 software design and test work。 Making ATMEGA8 as center of this control system， DC voltage as input signal， collecting input signal and converting it to fact value of voltage， at last SCM transfer it to PC software， we can save data of value of voltage in PC。 Work process： SCM initialize inner function which is used in work， then wait for mand from PC software； After receiving collecting mand from PC software， SCM begin to collect voltage from PC0 port and finish A/D convertion； reading data which has been converted and calculating fact value of voltage which been collected； we only save single decimal with data which has been converted， then BCD coding with every bit， at last send to PC software by asynchronous munication pattern； PC software realtime displays the result in GUI， we can artificial save result； Keyword： AVR； ATMEGA8； collect voltage； munication； MAX232 遼寧科技大學(xué)信息技術(shù)學(xué)院 3 3 目錄 基于 AVR 單片機(jī)的通訊系統(tǒng)設(shè)計(jì) ............................................................................................ 1 摘 要 ........................................................................................................................................ 1 ABSTRACT .................................................................................................................................. 2 第一章 緒論 .............................................................................................................................. 5 前言 ................................................................................................................................... 5 設(shè)計(jì)本系統(tǒng)的背景 .............................................................................................................. 5 單片機(jī)的發(fā)展 .............................................................................................................. 6 通信技術(shù)的發(fā)展 .......................................................................................................... 7 系統(tǒng)結(jié)構(gòu) ............................................................................................................................ 7 系統(tǒng)硬件設(shè)計(jì) .............................................................................................................. 7 系統(tǒng)軟件設(shè)計(jì) .............................................................................................................. 8 可行性分析 ........................................................................................................................ 9 第二章 系統(tǒng)使用的通信方式及協(xié)議介紹 ............................................................................ 10 通信方式 .......................................................................................................................... 10 串行通信與并行通信 ................................................................................................. 10 同步通信與異步通信 ................................................................................................. 10 RS232協(xié)議介紹 ................................................................................................................ 12 概述 .......................................................................................................................... 12 電氣特性 ................................................................................................................. 12 RS232C 的接口信號(hào) .............................................................................................. 13 第三章 系統(tǒng)硬件設(shè)計(jì) ............................................................................................................ 16 ATMEGA8介紹 ..................................................................................................................... 16 ........................................................................................................................... 16 .................................................................................................. 17 .................................................................................................................... 18 ATmega8同步 /異步串行接口 USART .......................................................................... 19 ATmega8 通用 I/O口 .................................................................................................. 26 ATmega8 A/D 轉(zhuǎn)換 ...................................................................................................... 29 MAX232介紹 ...................................................................................................................... 34 原理 .................................................................................................................