【正文】 放音輸出方式 音質(zhì)好，電壓范圍寬，應(yīng)用靈活(2) ISD1730電特性： 記錄,不僅把函數(shù),還有快進(jìn),抹去,音量控制,直接播放和復(fù)位等功能這些函數(shù)可以簡(jiǎn)單地通過完成按鍵。而放音指針則指向剛剛錄完的那段語(yǔ)音地址。在放音期間， LED 燈會(huì)閃爍直到放音結(jié)束時(shí)熄滅。當(dāng)放音停止，播放指針會(huì)停留在當(dāng)前停止的語(yǔ)音段起始位置。當(dāng)下降沿來到 FWD 端時(shí)，快進(jìn)操作還要決定于芯片當(dāng)時(shí)的狀態(tài)： 如果芯片在掉電狀態(tài)并且當(dāng)前播放指針的位置不在最后一段，那么指針會(huì)前進(jìn)一段，到達(dá)下一段語(yǔ)音處。 (4) 擦除操作： 擦除操作分為單段擦除和全體擦除兩種擦除方式，區(qū)別如下： 單個(gè)擦除：只有第一段或最后一段語(yǔ)音可以被單個(gè)擦除。 如果芯片空閑并且播放指針指向沒有指向第一或最后一段語(yǔ)音，則不會(huì)刪除任何語(yǔ)音，播放指針也不會(huì)被改變 當(dāng) RESET 被觸發(fā)，芯片將播放指針和錄音指針都放置在最后一段語(yǔ)音信息的位置。復(fù)位操作會(huì)將音量檔放在默認(rèn)位置，即最大音量。4． ISD1730引腳介紹圖35 ISD1730芯片 MIC+ 麥克風(fēng)輸入 + MIC 麥克風(fēng)輸入 VSSP2 負(fù)極 PWM 喇叭驅(qū)動(dòng)器地 SP 喇叭輸出 VCCP PWM 喇叭驅(qū)動(dòng)器電源 SP+ 喇叭輸出 + VSSP1 正極 PWM 喇叭驅(qū)動(dòng)器地 AUD/ AUX 輔助輸出，決定于 APC 寄存器的 D7 ，用來輸出一個(gè) AUD 或 AUX 輸出。 APC 寄存器的 D9 可以使其掉電。該管腳有一個(gè)內(nèi)部上拉設(shè)備和一個(gè)內(nèi)部防抖動(dòng)電路 ，允許使用按鍵開關(guān)來控制開始和結(jié)束。本設(shè)計(jì)中選用的放大器是LM386，LM386是為低電壓應(yīng)用設(shè)計(jì)的音頻功率放大器，其工作電壓為6V。 LED顯示電路設(shè)計(jì)LED（Light Emitting Diode），發(fā)光二極管，是一種固態(tài)的半導(dǎo)體器件，它可以直接把電轉(zhuǎn)化為光。因此LED顯示屏的驅(qū)動(dòng)器的設(shè)計(jì)起著舉足輕重的作用。每路最大可輸出35 mA的電流(不是恒流)。和很多應(yīng)用術(shù)語(yǔ)一樣，LED圖文顯示屏并沒有一個(gè)公認(rèn)的嚴(yán)格的定義，一般把顯示圖形和/或文字的LED顯示屏稱為圖文屏。只控制開關(guān)的圖形顯示,每個(gè)LED發(fā)光設(shè)備擁有一個(gè)比特的數(shù)據(jù),需要LED照明燈裝置在數(shù)據(jù)對(duì)應(yīng)填1,否則為0。文字的點(diǎn)陣格式比較規(guī)范，可以采用現(xiàn)行計(jì)算機(jī)通用的字庫(kù)字模。整機(jī)以AT89C52單片機(jī)為核心，通過單片機(jī)片控制一個(gè)行驅(qū)動(dòng)器74LS154和八個(gè)列驅(qū)動(dòng)器74HC595來驅(qū)動(dòng)顯示屏顯示。至此，一幅完整的文字信息就顯現(xiàn)出來。試驗(yàn)表明當(dāng)輸入LED的電流為15mA時(shí)，維持時(shí)間至少需要1ms，否則LED呈微亮狀態(tài)。 2．列驅(qū)動(dòng)芯片74HC595在5V供電的時(shí)候能夠達(dá)到30MHz的時(shí)鐘速度，每個(gè)并行輸出端口均能承受20mA的灌電流和拉電流。74HC595并行輸出端與LED模塊列線之間通過20Ω的電阻連接，這里電阻起到分壓，去除紅色LED的并聯(lián)嵌位作用。輕則對(duì)周圍無線電環(huán)境造成電磁污染，重則使系統(tǒng)時(shí)鐘紊亂，邏輯錯(cuò)誤。3．集成驅(qū)動(dòng)芯片在本設(shè)計(jì)中集成驅(qū)動(dòng)芯片是為了節(jié)省I/O口，通過整合驅(qū)動(dòng)信號(hào)做到時(shí)間上的匹配，保證系統(tǒng)的正常運(yùn)行。通過上面的分析,可以總結(jié)出列驅(qū)動(dòng)電路的功能。74HC24516*16LED點(diǎn)陣列驅(qū)動(dòng)行驅(qū)動(dòng)列驅(qū)動(dòng)列驅(qū)動(dòng)列驅(qū)動(dòng)16*16LED點(diǎn)陣16*16LED點(diǎn)陣16*16LED點(diǎn)陣圖37 LED電路設(shè)計(jì)程圖 根據(jù)以上芯片介紹，組合的電路必須有一個(gè)穩(wěn)定的電源作為輸出，但在公交車上現(xiàn)有的電源電壓對(duì)于單片機(jī)或者語(yǔ)音芯片來說電壓是偏高的，并且也不穩(wěn)定，為了讓我們的原理實(shí)現(xiàn)并運(yùn)用到現(xiàn)實(shí)社會(huì)中，我們必須一個(gè)穩(wěn)壓電源只有這樣才能保證電路正常運(yùn)行。此外，由于開關(guān)穩(wěn)壓電源熱損失的減少，設(shè)計(jì)時(shí)我們還可提高穩(wěn)壓電源的輸入電壓，所以穩(wěn)壓電路的設(shè)計(jì)如圖38所示。主程序流程如圖41所示。放音程序流程如圖43所示。通過這一個(gè)月我了解了元器件的工作原理，特殊性及運(yùn)用方法，在網(wǎng)上大量視頻的幫助下順利完成設(shè)計(jì)。即可以再程度上限制私人車輛的出行，減少堵車，又可以減少城市污染。llYou cannot miss out the Autumn of Arxan. It is definitely the best with brightlycolored scenery full of emotions. s time for the wild fruits to ripe. The picturesque Arxan in Autumn is indeed a fairyland only exists in a dream that satisfies all your fantasies. If its Day on February 14, characterized by bouquets of roses, chocolates and romantic candlelight dinners, than they do about their homegrown day for lovers. Even Qixi is nowadays referred to as the Chinese Valentine39。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 day, and I thought it was her who put the flower there. But the truth is not. It was the humble guy sitting in front of me. He just simply said ,”well, I caught sight of this flower and thought that it’s beautiful and you may like it”. I wonder why I was moved because of these simple words and present. Maybe it is the sincerity and the true self that impress me. I thanked him and some colleagues walked past my desk would appreciate the beautiful flower and they noticed that something romance happened there. Then later on, there were some little surprises once in a while. Once, there was something wrong with my drawer and I had plained about it unconsciously. And he fixed it for me. Then the other day, he placed several pink diamond roses beside the flower with a piece of paper saying” I love you more than I can say! Diamond stands for marriage, rose stand for love. I hope you are mine, bee my wife. You are the only girl who I really want to spend the rest of my life to stand by.” Although there were some grammar errors but I got what he meant. He meant so clear and so direct. s Day! in shops, hotels and restaurants. But few young women will mark the festival with their boyfriends, or take part in traditional activities to pray for cleverness. A largescale of exhibition on the Silk Road opened to the public in the National Museum on Thursday. The exhibition displays more than 400 treasures from Shaanxi province, Gansu province and 14 other regions. It is largest scale exhibition that shows the history of the Silk Road in recent years. Ass 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 Mi