【正文】 additional plugins for the 8channel signal conditioning board (a threeway onboard processing circuit, a total of 24 road, you can approach the basis of sensor signals, changes in signal conditioning channel plate). Compact system, the entire panel design, elegant appearance. System consists of signal conditioning systems and signal acquisition, processing system constituted of two parts. Signal conditioning system from the charge to enlarge, zoom in or currentvoltage amplifier circuit (depending on sensor type setting), programcontrolled zoom, programmable lowpass filtering, amplification, such as a buffer circuit posed of four levels, including singlechip control of PC by the request to enlarge the program, programcontrolled parameters such as lowpass filter. Signal acquisition, processing system to be adopted ARM + FPGA structures. The benefits of such a structure are: the difficulty of the smaller hard。s storage space smaller, while the standard Linux is a PC, and the need for the process of reducing the Linux kernel. For some added or removed independently of the function block can be retained only the kernel embedded system the functionality required to support the module, remove unwanted features. In order to meet certain realtime requirement and should not shield the kernel virtual memory management mechanism for enhanced realtime Linux. Computer systems are X86 motherboard architecture, patible desktop PC version of Linuxi386. In this way, we can directly use the X86 system, the core of the piler on Linux to pile the source code directly and cutting, and to avoid the core of the Linux source code part of involving CPU module and memory management module changes. Increase in file system and GUI based on system needs, the file system should include: the basic file system structure, the basic application, the basic configuration file, the basic equipment / dev / hd * and / dev / tty *, the basic procedures required to run the function library . GUI is a visual design software indispensable, but also for the future maintenance of onsite visual inspection of the interface. Guide the preparation of Linux code, the system will start as diskonchip equipment, guidance on the code on diskonchip. Power system after the boot code from the basic hardware initialization, and then the kernel image into memory by the run. Embedded systems is usually a pact hardware platform, a dedicated and strong at the core of the processor, while a small number of peripherals bined with the application of relevance, the characteristics of diversity。參考文獻1 李全利，仲偉峰，：136頁138頁2 ，：59頁60頁3 陳小忠，黃寧，：88頁89頁，105頁108頁4 朱飛，：282頁292頁5 沈文，Ealg lee，：59頁60頁6 Richard Barnett，Larry O’Cull，Sarah Cox， ，：66頁68頁7 ，：37頁40頁8 ，：95頁98頁9 ，：397頁399頁10 ，：108頁110頁11 ，：195頁198頁12 王正洪，朱正偉，：73頁75頁13 姜立東，：152頁156頁14丁化成，耿德根，：203頁206頁15 王保義，：145頁150頁16 Wayne Wolf（美）.High Performance Embedded ，：336頁338頁17 Raj Systems Architecture Programming and ，：286頁287頁18 Stephen E. Derenzo（美）.Practical Interfacing in the ，：204頁206頁附錄AEmbedded Linuxbased acquisition systemWith the rapid development of information technology, people need to accurate, fast and convenient access to large amounts of data and be able to quickly extract useful information. Embedded Systems is the IT network technology and a new direction of technology development. American futurist Timor predicted during his visit to China in 1999: 4 ~ 5 years after the tool will be embedded PC and the Internet is the second greatest invention after. 20th century 9039?；叵脒@四年的學(xué)習(xí)時光，有歡笑，有淚水，有收獲。同時對xx等同學(xué)表示忠心的感謝，在畢業(yè)設(shè)計的過程中他們給我提供了很大的幫助。在設(shè)計過程中，x老師對我嚴格要求，每一步都親自把關(guān)，每遇到困難，他都認真講解，深入淺出，不厭其煩，最終保證了該設(shè)計的順利完成。致謝本課題是在xx老師的精心指導(dǎo)下完成的，首先向xx老師表示最崇高的感謝。本采集系統(tǒng)設(shè)計了3個按鍵，通過按鍵可使使系統(tǒng)完成數(shù)據(jù)采集、顯示及傳輸；顯示部分則采用LCD1602液晶顯示器，價格便宜，接口及控制簡單。溫濕度采集模塊采用SHT75數(shù)字傳感器，可直接與單片機相連進行數(shù)據(jù)采集、分析及顯示，而壓力傳感器采用型號為26PCB的傳感器，直接與單片機的ADC接口相連。深入討論程序設(shè)計、硬件設(shè)計、液晶顯示設(shè)計等內(nèi)容，整個系統(tǒng)分為5個模塊。 30 結(jié)論本論文提出了以Atmega64單片機為核心結(jié)構(gòu)，進行數(shù)據(jù)實時采集的實施方案設(shè)計。千萬不要刪除行尾的分節(jié)符，此行不會被打印。系統(tǒng)上電后通過主程序調(diào)用各模塊子程序進行測量，處理并傳輸。為了便于系統(tǒng)功能擴展，采用了模塊化結(jié)構(gòu)，除RS232接口通信程序采用匯編語言編程外，其他均采用C語言編寫。指令11：讀數(shù)據(jù)。1602模塊必須在不忙時進行數(shù)據(jù)寫入操作。指令8：DDRAM地址設(shè)置。指令6：功能設(shè)置命令，DL為1時為4位總線，0時為8位總線；N為1時雙行顯示，0時為單行顯示。D為1表示開顯示，0為關(guān)顯示；C為1表示右光標，0表示無光標；B為1表示光標閃爍，0為不閃爍。I/D為光標移動方向，1右移，0左移。光標返回到地址00H。清屏?xí)r光標復(fù)位到00H。對1602的顯示控制通過指令代碼實現(xiàn)。軟件去抖實際上采用的是延時的方法，避開按鍵的抖動部分時間。這里說的抖動是鍵盤的機械抖動，此過程持續(xù)時間為10~200ms。程序留流程圖如圖44所示，詳細程序見附錄D。首先設(shè)置Atmega64單片機TWI(I2C)模塊的時鐘源和波特率，在I2C的寫函數(shù)中完成器件尋址、輸出指令或數(shù)據(jù)等功能以實現(xiàn)對AT24C64芯片數(shù)據(jù)存儲功能。唯一需要注意的是通過單片機的I/O口控制RS422的發(fā)送和接收端口，與MAX232程序類似，程序源代碼見附錄D。一幀發(fā)完清TIINC R0DJNZ R7， NEXTSJMP $ 。發(fā)送數(shù)據(jù)JNB TI, $ 。R0指示發(fā)送緩沖區(qū)首址MOV R7, 7 。啟動T1MOV SCON， 50H 。T1方式2MOV TH1， 0E6HMOV TL1， 0E6H 。PC的接收程序用TURBO C完成，利用庫函數(shù)inportb()完成對8250端口的寫操作，其具體接收子程序詳見附錄D。(3)狀態(tài)字（LSR）狀態(tài)寄存器LSR用來向CPU提供接收和發(fā)送過程中產(chǎn)生的狀態(tài)，這些狀態(tài)可用于CPU查詢，如果允許中斷，也可引起中斷。T1初始化，啟動T1工作設(shè)定串行通信方式設(shè)置發(fā)送數(shù)據(jù)塊首地址發(fā)送數(shù)據(jù)T1=1?清T1修改數(shù)據(jù)指針和數(shù)據(jù)塊長度計數(shù)器全部數(shù)據(jù)發(fā)送完？結(jié)束圖43 RS232傳輸程序歷程圖針對上述步驟作如下說明：(1)波特率除數(shù)鎖存器（BRD），波特率除數(shù)（BRD）和波特率（Baud）的關(guān)系為： BRD=時鐘頻率/（16Baud） (41)如：Baud=1200bps,則BRD=106/（161200）=0060H。對發(fā)送緩沖器寫，即啟動發(fā)送過程。，同時使其最高位DLAB為“0”，選中發(fā)送緩沖器和接受緩沖器，以便后面進行發(fā)送和接收。表41 可編程串行接口DLAB選擇寄存器地址0發(fā)送緩沖器THR（寫）3F8H0接收緩沖器RDR（讀）3F8H1除數(shù)鎖存器BRDL（低8位）3F8H1除數(shù)鎖存器BRDH（高8位）3F9H0中斷允許寄存器3F9HX中斷識別寄存器IIR3FAHX線路控制寄存器LCR3FBHXModem控制寄存器MCR3FCHX傳輸線狀態(tài)寄存器LSR3FDHXModem狀態(tài)寄存器MSR3FEH由于地址3F8H和3F9H為兩個寄存器共用，由線路控制寄存器最高位DLAB進行選擇。要實現(xiàn)單片機與PC際之間順利的通訊，首先要對PC機串行接口由簡單的了解，PC的串行通訊接口使用的是8由于單片機的串行發(fā)送和接收線TXD和RXD是TTL電平，而PC的COM1或COM2的RS232C連接器（D型9針插座）是EIA電平，因此單片機需加接MAX232芯片，通過串行電纜和PC相連接。程序清單見附錄2。隨后設(shè)置濕度啟動命令，轉(zhuǎn)換完成后，進行濕度變換和濕度的補償計算。程序中，通過PCPC3模擬進行I2C協(xié)議進行通信。如果沒有用CRC8的校驗和，則控制器就會自動返回休眠模式?？刂破鞅仨毻ㄟ^使DATA為低來確認每一字節(jié)，所有的矢量中從右算MSB（最高位）列于第一位。為表明測量完成，SHT75會使數(shù)據(jù)線為低電平，此時控制器必須重新啟動SCK。當發(fā)出了溫濕度測量命令后，控制器需要等到測量完成，方可讀取結(jié)果。 如果與SHT75傳感器的通信中斷，下列信號順序會使串口復(fù)位，當使DATA線處于高電平時，觸發(fā)SCK9次以上（含