【正文】 s Day. More and more young Chinese people begin to celebrate this day in a very similar way as that in western countries. Fewer people than ever will gaze at the heavens on Saturday to pick out the two stars shining bright on either side of the Milky Way, that is, if people even know on which day Qixi falls. There are ready reminders dotted about, in the form of big ads saying Sales on Chinese Valentine39。Autumn in the northern part of the country es earlier than the South. A September rain followed by the footprints of Autumn brings more colors to the once emerald green mountain and blooming grassland. 其次要感謝大學幾年來所有的老師，為我們打下了專業(yè)知識的基礎。 user_1()。 }}/*主函數(shù)*/void main(){ DDRD=0xB0。 //show_volt(volt)。 } else if(down==0) { volt。 if(==1) { volt=0。 Enable=0。 return freeback_volt。 } for(i=0。 } } } freeback_amp=(ampdata[24]+ampdata[25]+ampdata[26])/3。 //delay_ms(2)。 delay_ms(4)。 delay_ms(4)。 show_data( data)。 delay_ms(4)。)。 } }/*顯示數(shù)據(jù)函數(shù)，將數(shù)據(jù)分開*/void show_data(uint data){ char ch1,ch2,ch3。i++) { write_data(putvolt[i])。 delay_ms(5)。i16。39。i8。//flash uchar error[]=error。而用1602液晶顯示，則占用端口少，顯示功能較全面，驅動電流小。如果AVR的I/O口設置為輸出方式工作，當其輸出高電平時，能夠輸出20mA的電流，而當其輸出低電平時，可以吸收40mA的電流。GND: 芯片接地引腳，使用時接地。鍵盤單片機電路系統(tǒng)結構如圖1所示，系統(tǒng)選用Atmage16單片機為控制核心，外部擴展1602驅動芯片用以實現(xiàn)電壓輸出功能，同時1602液晶顯示相應的輸出電壓值。 三端集成穩(wěn)壓芯片 方案一:采用LM317可調式三端穩(wěn)壓器電源 LM317可調式三端穩(wěn)壓器電源能夠連續(xù)輸出可調的直流電壓.,不過它只能連續(xù)調正電壓，穩(wěn)壓器內部含有過流，過熱保護電路。由于整個控制過程是一個負反饋過程，所以這樣的穩(wěn)壓電源叫串聯(lián)負反饋穩(wěn)壓電源。通過步進增減按鍵功能選擇可在不同的設定參數(shù)之間切換，再按確認鍵進入設定電壓輸出狀態(tài)。從組成上，數(shù)控電源可分成器件、主電路與控制等三部分。智能穩(wěn)壓電源可利用單片機設置周密的保護檢測系統(tǒng)，確保電源運行可靠。利用分離器件組成，其體積大，功率底，可靠性差，操作使用不方便，自我保護功能不夠，因而故障率高。因此數(shù)控電源主要的發(fā)展方向，是針對上述缺點不斷加以改善。輸出電壓可用1602LCD液晶顯示。方案二：串聯(lián)型穩(wěn)壓電源并聯(lián)穩(wěn)壓電源有效率低、輸出電壓調節(jié)范圍小和穩(wěn)定度不高這三個缺點。我們在選擇方案的時候考慮到電路要簡單，元件要容易找，所以我們選擇了上述的方案中的第三個方案[1]。精度相對方案一要差，所以數(shù)字顯示部分采用方案一。AVcc：為端口A和片內ADC模擬電路電源輸入引腳。(2) 32根I/O引腳，分成PA、PB、PC和PD四個8位端口，他們全部, 編程控制的雙（多）功能復用的I/O引腳（口）。它可以先產生一定脈寬的PWM 波，作為L1603 驅動電路輸入信號，然后根據(jù)所需要的基準電壓與檢測到的輸出電壓的比較，調整脈寬，即改變占空比，最終實現(xiàn)高性能可調直流穩(wěn)壓 圖3內部晶體振蕩器外接電路 L6203驅動模塊L6203驅動模塊就是將5V的輸入電壓變成Vin的電壓24V，一方面提高電壓，一方面提高電流。flash uchar putvolt[]= Volt: 。 write_(0x80)。 for(i=0。 write_(0x80)。 for(i=0。 delay_ms(5)。i16。 delay_ms(4)。 } else { write_data(0x30+ch1)。 write_data(0x30+ch3)。 ch3=data/10%10。 write_data(0x30+ch2)。 for(chi=0。j++) { if(ampdata[i]ampdata[j]) { temp=ampdata[i]。chi30。 data[i]=data[j]。 delay_ms(3)。 delay_ms(50)。 Enable=1。 } if(volt120) { volt=120。 while(~ok)。 intosys()。 在這里首先向治學嚴謹，誨人不倦的老師表示我最衷心的感謝！本次設計從最初的選題到任務的制定，系統(tǒng)的設計與開發(fā)及在論文的撰寫過程中都得到了老師的悉心指導與幫助。Nestled close to the country39。s misery, the cow told him to turn its hide into a pair of shoes after it died. The magic shoes whisked Niulang, who carried his two children in baskets strung from a shoulder pole, off on a chase after the empress. The pursuit enraged the empress, who took her hairpin and slashed it across the sky creating the Milky Way which separated husband from wife. But all was not lost as magpies, moved by their love and devotion, formed a bridge across the Milky Way to reunite the family. Even the Jade Emperor was touched, and allowed Niulang and Zhinu to meet once a year on the seventh night of the seventh month. This is how Qixi came to be. The festival can be traced back to the Han Dynasty (206 BCAD 220). Traditionally, people would look up at the sky and find a bright star in the constellation Aquila as well as the star Vega, which are identified as Niulang and Zhinu. The two stars shine on opposite sides of the Milky Way. Customs In bygone days, Qixi was not only a special day for lovers, but also for girls. It is also known as the Begging for Skills Festival or Daughters39。is going on in Beijing, the exhibit aims to show the world this brilliant section of history. The Silk Road is a series of trade and cultural transmission routes that were central to cultural interaction through regions of the Asian continent. It connected the West and East by linking traders, merchants, pilgrims, monks, soldiers, nomads, and urban dwellers from China and India to the Mediterranean Sea during various periods of time. I met my dear hubby in 2009 the second year I was in my school and it was the first year when he came here. We became colleagues. And there was nothing special happening during that year. He was just a kind and humble brother graduated from the same college as me. But we did not know each other till he became my colleague and his office desk was just in front of me. There was only a glass between us. So actually we could see each other when we both look up. But it is not the main reason that really draws us close. How we bee close to each other was something seems quite natural. We went out to play badminton with other colleagues and we sometimes chatted for a while. He is a man of few words but somehow sometimes will say something really humorous. Then one day, to my great surprise, I found a pot of beautiful flower on my desk. It was just the flower I had talked about with my colleague the other d