【正文】 .................................................................... (12) 概述 ........................................................................................................................ (12) 發(fā)射程序 ................................................................................................................ (13) 接收程序 ................................................................................................................ (17) 4 結(jié)束語(yǔ) ................................................................................................................................... (21) 參 考 文 獻(xiàn) ........................................................................................................................... (22) Abstract.................................................................................................................................. (23) 第 1 頁(yè)（共 23 頁(yè)） 基于 AT89S51 單片機(jī)無(wú)線傳輸系統(tǒng)設(shè)計(jì) 作 者： 指導(dǎo)教師： 摘要 ：當(dāng)今社會(huì)發(fā)展迅速 ,人們迫切的期望能隨時(shí)隨地、不受時(shí)空限制地進(jìn)行信息交互。 [1]在有線數(shù)據(jù)傳輸方式當(dāng)中 ,數(shù)據(jù)的傳輸載體是雙絞線、同軸電纜或光纖。給出了無(wú)線數(shù)據(jù)傳輸系統(tǒng)的工作原理、硬件設(shè)計(jì)方案和軟件設(shè)計(jì)方案。 圖 2 無(wú)線數(shù)據(jù)傳輸原理 無(wú)線數(shù)據(jù)傳輸常用編碼方式 第一種 :FSK 式（移頻鍵控方式 Frequency Shift Keying） , 又稱數(shù)字調(diào)頻。在兩個(gè)相鄰的頻率跳變的碼元之間，其相位通常是不連續(xù)的。但每一個(gè)碼元都被調(diào)成兩個(gè)電平，所以數(shù)據(jù)傳輸速率只有調(diào)制速率的 1/2。其編碼容量大 ,保密性好。當(dāng) MCU 的任務(wù)不是很繁重時(shí) ,可以考慮使用軟件解碼。 (4)檢驗(yàn)接收信息的正確性。射頻接收模塊接收發(fā)射的已調(diào)制信號(hào)，并對(duì)信號(hào)進(jìn)行解調(diào)恢復(fù)原來(lái)的調(diào)制信號(hào)。 RX Mode: (9) 標(biāo)準(zhǔn) DIP 間距接口，便于嵌入式應(yīng)用 (10) RFModuleQuickDEV 快速開發(fā)系統(tǒng)，含開發(fā)板 工作模式及芯片結(jié)構(gòu) nRF905 有兩種工作模式和兩種節(jié)能模式。 nRF905 片內(nèi)集成了電源管理、晶體振蕩器、低噪聲放大器、頻率合成器、功率放大器等模塊，曼徹斯特編碼／解碼由片內(nèi)硬件完成，無(wú)需用戶對(duì)數(shù)據(jù)進(jìn)行曼徹斯特編碼，使用非常方便。采用高頻調(diào)制的無(wú)線數(shù)據(jù)傳輸信號(hào)抗干擾 能力強(qiáng) ,使無(wú)線數(shù)據(jù)傳輸信號(hào)易于分離和區(qū)別 。 SPI 讀操作如圖 8，寫操作如圖 9 圖 8 SPI 讀操作 圖 9 SPI 寫操作 SPI 接口由狀態(tài)寄存器、射頻配置寄存器、發(fā)送地址寄存器、發(fā)送數(shù)據(jù)寄存器和接收數(shù)據(jù)寄存器 5 個(gè)寄存器組成。讀操作全部從字節(jié) 0開始。HFREQ_PLL=h。 發(fā)射程序 include include define uint unsigned int define uchar unsigned char sbit TX_EN= P3^5。 sbit SCK=P1^7。 for(i=0。 Delay(10)。 CSN=0。 CSN=0。 //使能發(fā)射模式 // Delay(500)。 Delay(2)。 //接收發(fā)送有效數(shù)據(jù)長(zhǎng)度為 3第 15 頁(yè)（共 23 頁(yè)） 字節(jié) SpiWrite( 0xE7)。 TX_EN=0。 PWR_UP=1。 while(!key2)。 key_value=0x00。 sbit PWR_UP=P0^2。 sbit led1=P1^1。i++) _nop_()。 Delay(10)。 Delay(10)。 CSN=0。SpiWrite(0xE7)。 Delay(1000)。 while(DR)。 } else if(TxRxBuffer[2]==0xa1) { led2=~led2。 led3=0。 //等待接收完成 if(success_flag) { TX_EN=0。這種編碼方法在基于 AT89S51 單片機(jī)的無(wú)線數(shù)據(jù)傳輸設(shè)計(jì)中得到了應(yīng)用。它不僅降低了成本，同時(shí)也增加了無(wú)線數(shù)據(jù)傳輸接收的靈活性，對(duì)不同的無(wú)線數(shù)據(jù)傳輸模塊，不用更換系統(tǒng)硬件電路，只需要修改程序即可。t appealed against the disciplinary action your employer has taken against you. However, if you win your case, the tribunal may reduce any pensation awarded to you as a result of your failure to appeal. Remember that in most cases you must make an application to an employment tribunal within three months of the date when the event you are plaining about happened. If your application is received after this time limit, the tribunal will not usually accept i. If you are worried about how the time limits apply to you, take advice from one of the anisations listed under Further help. Employment tribunals are less formal than some other courts, but it is still a legal process and you will need to give evidence under an oath or affirmation. Most people find making a claim to an employment tribunal challenging. If you are thinking about making a claim to an employment tribunal, you should get help straight away from one of the anisations listed under Further help. If you are being represented by a solicitor at the tribunal, they may ask you to sign an agreement where you pay their fee out of your pensation if you win the case. This is known as a damagesbased agreement. In England and Wales, your solicitor can39。s governing body, has also ordered an immediate investigation into the referee39。 Junior high school, thought to have a crush on just means that the real growth, but over the past three years later, his writing of alumni in peace, suddenly found that isn39。想要的，不想要的，界限明確，好像沒有什么可以撼動(dòng)自己。t start planning... Those years, those days of do, finally, like youth, will end in our life. 此刻，天空是陰暗的，空氣里有著剛下過雨之后的清新因子。 Baumgartner the disappointing news: Mission aborted. r plays an important role in this mission. Starting at the ground, conditions have to be very calm winds less than 2 mph, with no precipitation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our daytoday weather lives. It will climb higher than the tip of Mount Everest ( miles/ kilometers), drifting even higher than the cruising altitude of mercial airliners ( miles/ kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence. The supersonic descent could happen as early as Sunda. The weatheThe balloon will slowly drift to the edge of space at 120,000 feet ( Then, I would assume, he will slowly step out onto something resembling an Olympic diving platform. Below, the Earth bees the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, he39。嫌惡過自己的怯懦，最終卻發(fā)現(xiàn)有很多 緣分 ，有很多錯(cuò)過，好像冥冥之中真的已經(jīng)注定。 Then in high school, think don39。s plaint. In a statement the Russian side added: We found no racist insults from fans of CSKA. Age has reached the end of the beginning of a word. May be guilty in his seems to passing a lot of different life became the appearance of the same day。re clear about the terms of the agreement. It might be best to get advice from an experienced adviser, for example, at a Citizens Advice Bureau. To find your nearest CAB, including those that give advice by , click on nearest CAB. For more information about making a claim to an employment tribunal, see Employment tribunals. The (lack of) air up there Watch mCayman Islandsbased W