【正文】 the device is not much connection between the , but the puter is not the same circuit, it is a microprocessor core, the device must be connected with the microprocessor, the device must be coordination between, so they need to connect on a lot, as if still analog circuit like the microprocessor and devices in the connection between the individual, the number of lines will be a little more surprising, therefore the introduction of the microprocessor bus Zhong Each device Gongtong access connections, all devices 8 Shuju line all received eight public online, that is the equivalent of all devices together in parallel, but only this does not work, if there are two devices send data at the same time, a 0, a 1, then, whether the receiver received what is it? This situation is not allowed, so to be controlled by controlling the line, timesharing the device to work at any time only one device to send data (which can have multiple devices to receive both). Device39。你完全可以在指令中按排一條SETB ，并且當(dāng)單片機執(zhí)行到這條指令時，但使用者不會這么去做，因為這通常會導(dǎo)致系統(tǒng)的崩潰。 某些專用單片機設(shè)計用于實現(xiàn)特定功能，從而在各種電路中進(jìn)行模塊化應(yīng)用，而不要求使用人員了解其內(nèi)部結(jié)構(gòu)。 Philips公司以其在嵌入式應(yīng)用方面的巨大優(yōu)勢，將MCS51從單片微型計算機迅速發(fā)展到微控制器。這種計算機就是把智能賦予各種機械的單片機（亦稱微控制器）。概括的講：一塊芯片就成了一臺計算機?；谶@一系統(tǒng)的單片機系統(tǒng)直到現(xiàn)在還在廣泛使用。隨著工業(yè)控制領(lǐng)域要求的提高，開始出現(xiàn)了16位單片機，但因為性價比不理想并未得到很廣泛的應(yīng)用。它的體積小、質(zhì)量輕、價格便宜、為學(xué)習(xí)、應(yīng)用和開發(fā)提供了便利條件。顧名思義，這種計算機的最小系統(tǒng)只用了一片集成電路，即可進(jìn)行簡單運算和控制。因此，當(dāng)我們回顧嵌入式系統(tǒng)發(fā)展道路時，不要忘記Intel和Philips的歷史功績。如音樂集成單片機，看似簡單的功能，微縮在純電子芯片中（有別于磁帶機的原理），就需要復(fù)雜的類似于計算機的原理。四、程序的執(zhí)行過程：單片機在通電復(fù)位后8051內(nèi)的程序計數(shù)器（PC）中的值為‘0000’，所以程序總是從‘0000’單元開始執(zhí)行，也就是說：在系統(tǒng)的ROM中一定要存在‘0000’這個單元，并且在‘0000’單元中存放的一定是一條指令。s data connection is known as the data bus, the device is called line of control all the control bus. Internal or external memory in the microcontroller and other devices have memory cells, the memory cell to be assigned addresses, you can use, distribution, of course, to address given in the form of electrical signals, and as more memory cells, so, for the address allocation The line is also more of these lines is called the address bus.Second, data, address, mandThe reason why these three together because of the nature of these three are the same the number, or are a string of 39。unit must be stored in a single instruction. 5, the stack: Stack is a region, is used to store data, there is no special about the region itself is a part of internal RAM, special access to its data storage and the way that the socalled 39。 units started, that is: the system must exist in ROM 0000 39。s responsibility inevitably falls on electrical, electronics manufacturers. From this point of view, Intel faded MCU development has its objective factors. In the development of MCU, the most famous manufacturers as the number of Philips Corporation. Philips pany in embedded applications, its great advantage, the MCS51 singlechip microputer from the rapid development of the microcontroller. Therefore, when we look back at the path of development of embedded systems, do not forget Intel and Philips in History. Embedded SystemsEmbedded system microcontroller is an independent development path, the MCU important factor in the development stage, is seeking applications to maximize the solution on the chip。事實上‘不能作為通用I/O口使用’也并不是‘不能’而是（使用者）‘不會’將其作為通用I/O口使用。 單片機在醫(yī)用設(shè)備中的用途亦相當(dāng)廣泛，例如醫(yī)用呼吸機，各種分析儀，監(jiān)護(hù)儀，超聲診斷設(shè)備及病床呼叫系統(tǒng)等等。在發(fā)展MCU方面，最著名的廠家當(dāng)數(shù)Philips公司。還有一類計算機，大多數(shù)人卻不怎么熟悉。相當(dāng)于一個微型的計算機，和計算機相比，單片機只缺少了I/O設(shè)備。此后在8031上發(fā)展出了MCS51系列單片機系統(tǒng)。90年代后隨著消費電子產(chǎn)品大發(fā)展，單片機技術(shù)得到了巨大提高。同時，學(xué)習(xí)使用單片機是了解計算機原理與結(jié)構(gòu)的最佳選擇。因為它體積小，通常都藏在被控機械的“肚子”里。 嵌入式系統(tǒng)單片機是嵌入式系統(tǒng)的獨立發(fā)展之路，向MCU階段發(fā)展的重要因素，就是尋求應(yīng)用系統(tǒng)在芯片上的最大化解決；因此，專用單片機的發(fā)展自然形成了SOC化趨勢。如：音樂信號以數(shù)字的形式存于存儲器中（類似于ROM），由微控制器讀出，轉(zhuǎn)化為模擬音樂電信號（類似于聲卡）。 五、堆棧：堆棧是一個區(qū)域，是用來存放數(shù)據(jù)的，這個區(qū)域本身沒有任何特殊之處，就是內(nèi)部RAM的一部份，特殊的是它存放和取用數(shù)據(jù)的方式，即所謂的‘先進(jìn)后出，后進(jìn)先出’，并且堆棧有特殊的數(shù)據(jù)傳輸指令，即‘PUSH’和‘POP’，有一個特殊的專為其服務(wù)的單元，即堆棧指針SP，每當(dāng)執(zhí)一次PUSH指令時，SP就（在原來值的基礎(chǔ)上）自動加1，每當(dāng)執(zhí)行一次POP指令，SP就（在原來值的基礎(chǔ)上）自動減1。0 39。advanced post out backward first out 39。, the process is always from the 000039。s hard drive in terms of nothing, but in terms of the MCU is not acceptable. SCM in the utilization of hardware resources to be very high for the job so although the original is still in the pilation of a lot of use. The same token, if the giant puter operating system and applications run up to get home PC, home PC, also can not afford to.Can be said that the twentieth century across the three power era, that is, the age of electricity, the electronic age and has entered into the puter age. However, this puter, usually refers to the personal puter, referred to as PC. It consists of the host, keyboard, monitor and other ponents. Another type of puter, most people do not know how. This puter is to give all kinds of intelligent machines single chip (also known as microcontroller). As the name suggests, this puter system took only a minimal integrated circuit, can be a simple operation and control. Because it is small, usually hidden in the charged me