电子信息工程外文翻译外文文献英文文献微处理器

外文资料所译外文资料：1. 作者G..Bouwhuis, J.Braat, A.Huijser2. 书名:Principles of Optical Disk Systems3. 出版时间：1991年9月4. 所译章节：Session 2/Chapter9, Session 2/Chapter 11原文：MicroprocessorOne of the key inventions in the history of electronics, and in fact one of the most important inventions ever period, was the transistor. As time progressed after the inven ti on of LSI in tegrated circuits, the tech no logy improved and chips became smaller, faster and cheaper. The functions performed by a processor were impleme nted using several differe nt logic chips. In tel was the first compa ny to in corporate all of these logic comp onents into a si ngle chip, this was the first microprocessor. A microprocessor is a complete computati on engine that is fabricated on a sin gle chip. A microprocessor executes a collecti on of machi ne in struct ions that tell the processor what to do. Based on the in struct ions, a microprocessor does three basic things: ing the ALU (Arithmetic/Logic Unit), a microprocessor can perform mathematical operatio ns like additi on, subtract ion, multiplicatio n and divisi on; 2.A microprocessor can move data from one memory location to another; 3.A microprocessor can make decisi ons and jump to a new set of in struct ions based on those decisi ons.There may be very sophisticated things that a microprocessor does, but those are its three basic activities. Microprocessor has an address bus that sends an address to memory, a data bus that can send data to memory or receive data from memory, an RD(read) and WR(write) line that lets a clock pulse sequenee the processor and a reset li ne that resets the program coun ter to zero(or whatever) and restarts executi on. And let ' s assume that both the address and data buses are 8 bits wide here.Here are the comp onents of this simple microprocessor:1. Registers A, B and C are simply latches made out of flip-flops.2. The address latch is just like registers A, B and C.3. The program coun ter is a latch with the extra ability to in creme nt by 1 whe n toldto do so, and also to reset to zero whe n told to do so.4. The ALU could be as simple as an 8-bit adder, or it might be able to add, subtract, multiply and divide 8- bit values. Let ' s assume the latter here.5. The test register is a special latch that can hold values from comparisons performed in the ALU.An ALU can normally compare two numbers send determine if they are equal, if one is greaterthan the other, etc. The test register can also normally hold a carry bit from the last stage of the adder. It stores these values in flip-flops and then the instruction decoder can use the values to make decisi ons.6. There are six boxes marked “3tate ” .Theseire tri-state buffers. A tri-state buffer can pass a 1, a0 or it can essentially disconnect its output. A tri-statebuffer allows multiple outputs to connect to a wire, but only one of then to actually drive a 1or a0 onto the line.7. The in structio n register and in structio n decoder are resp on sible for con trolli ng all of theother comp onen ts.Although they are not shown in this diagram, there would be control lines from theinstruction decoder that would:1. Tell the A register to latch the value currently on the data bus2. Tell the B register to latch the value currently on the data bus3. Tell the C register to latch the value currently on the data bus4. Tell the program counter register to latch the value currently on the data bus5. Tell the address register to latch the value currently on the data bus6. Tell the instruction register to latch the value currently on the data bus7. Tell the program coun ter to in creme nt8. Tell the program coun ter to reset to zero9. Activate any of the six tri-state buffers (six separate lin es)10. Tell the ALU what operati on to perform11. Tell the test register to latch the ALU ' s test bits12. Activate the RD line13. Activate the WR lineComi ng into the in structi on decoder are the bits from the best register and clock line, as well as the bits from the instruction register.RAM and ROM The address and data buses, as well as the RD and WR lines connect either to RAM or ROM —gen erally both. In our sample microprocessor, we have an address bus 8 bits wide and a data bus 8 bits wide. That means that the microprocessor an address (2 n) 256 bytes of the memory and it can read or write 8 bits of the memory at a time. Let ' s assume that this simple microprocessor has 128 bytes of ROM starti ng at address 0 and 128 bytes of RAM starti ng at address 128.ROM sta nds for read-only memory. A ROM chip is programmed with a perma nent collection of pre-set bytes. The address bus tells the ROM chip which byte to get and place on the data bus. When the RD line cha nges state, the ROM chip prese nts the selected byte onto the data bus.RAM sta nds for ran dom-access memory. RAM contains bytes of in formati on, and the microprocessor can read or write to those bytes depe nding on whether the RD or WR li ne is sig naled.One problem with today ' s^AM chips is that they forget everythi ng once the power goes off. That is why the computer n eeds ROM.By the way, n early all computers con tai n some amount of ROM (it is possible to create a simple computer that contains no RAM —many microcontrollers do this by placi ng a han dful of RAM bytes on the processor chip itself ——but gen erally impossible to create one that contains no ROM).On a PC, the ROM is called the BIOS (Basic Input/Output System). When the microprocessor starts, it begins executing instructions it finds in the BIOS. The BIOS instructions do things like test the hardware in the machine, and then it goes to the hard disk to fetch the boot sector. This boot sector is ano ther small program, and the BIOS store it in RAM after reading it off the disk. The microprocessor then begins executing the boot sector ' s instructions from RAM. The boot sector program will tell the microprocessor to fetch someth ing else from the hard disk into RAM, which the microprocessor the n executes, and so on. This is how the microprocessor loads and executes en tire operati ng system.Microprocessor In structio ns Eve n the in credibly simple microprocessor show n here will have a fairly large set of in structio ns that it can perform. The collectio n of in structi ons is impleme nted as bit patter ns, each one of which has a differe nt meaning when loaded into the instruction register. Humans are not particularly good at rememberi ng bit patter ns, so a set of short words are defi ned to represe nt the differe nt bit patter ns. This collect ion of words is called the assembly Ian guages of the processor. An assembler can tran slate the words into their bit patter ns very easily, and then the output of assembler is placed in memory for the microprocessor to execute. If you use C Ian guage program ming, a C compiler will tran slate the C code in to assembly Ian guage.So now the questi on is, “ How do all of these in structio ns look in ROM? ” Eacthese assembly Ian guage in struct ions must be represe nted by a binary nu mber.These nu mbers all know as recodes. The in structi on decoder n eeds to turn each of recodes into a set of sig nals that drive the differe nt comp onents in side the microprocessor. Let ' take the ADD instruction as an example and look at what it n eeds to do.During the first clock cycle, we need to actually load the instruction. Therefore the in structi on decoder n eeds to: activate the tri-state buffer for the program coun ter; activate the RD line; activate the data-in tri-state buffer; latch the instruction into the in structi on register.During the second clock cycle, the ADD instruction is decoded. It needs to do very little: set the operation of ALU to addition; latch the output of the ALU into the C register.During the third clock cycle, the program coun ter is in creme nted (in theory this could be overlapped into the sec ond clock cycle).Every in struct ion can be broke n dow n as a set of seque need operati ons like these that mani pulate the comp onents of microprocessor in the proper order. Some instructions, like this ADDinstruction, might take two or three clock cycles. Others might take five or six clock cycles.Microprocessor Performanee The number of transistors available has a huge effect on the performa nee of a processor. As see n earlier, a typical in struct ion in a processor like an 8088 took 15 clock cycles to execute. Because of the desig n of the multiplier, it took approximately 80 cycles just to do one 16-bit multiplication on the 8088. With more tran sistors, much more powerful multipliers capable of sin gle-cycle speeds become possible.More tran sistors also allow for a tech no logy called pipeli ning. In a pipeli ned architecture, i nstructio n executi on overlaps. So eve n though it might take five clock cycles to execute each instruction, there can be five instructions in various stages of executi on simulta neously. That way it looks like one in structi on completes every clock cycle.Many modern processors have multiple instruction decoders, each with own pipeline. This allows for multiple instruction streams, which means that more than one instruction can complete during each clock cycle. This technique can be quite complex to implement, so it can be lots of transistors.The trend in processor design has been toward full 32-bit ALU with fast floating point processors built in and pipelined execution with multiple instruction streams. There has also been a tendency toward special instructions that make certain operati ons particularly efficie nt. There has also bee n the additi on of hardware virtual memory support and L1 cach ing on the processor chip. All of these trends push up the transistor count, leading to the multi-million transistor powerhouses available today. These processors can execute about one billio n in structi ons per sec ond!The Operational Amplifier will continue to be a vital component of analog design because it is a fun dame ntal comp onent. Each gen erati on of electr onic equipme nt in tegrates more functions on silic on and takes more of the an alog circuitry in side the IC. As digital applicati ons in crease, an alog applicati ons also in crease because the predo minant supply of data and in terface applicati ons are in the real world, and the real world is an an alog world.The LM386 is a power amplifier designed for use in low voltage consumer applications. The gain is internally set to 20 to keep external part count low, but the additi on of an external resistor and capacitor betwee n pins 1 and 8 will in crease the gai n to any value from 20 to 2OO.The in puts are ground refere need while the output automatically biases to on e-half the supply voltage. The quiesce nt power drain is only 24 mill watts when operating from a 6 volt supply, making the LM386 ideal for battery operati on.A Crystal is a basic piezoelectric quartz crystal. On its own, it cannot gen erate electrical clocks. It has to be conn ected to a clock oscillator to get a clock waveform. There are two kinds of crystals: Series Resonant, which can be modeled as a high Q series LC circuit, and Parallel Resonant, which can be modeled as a high Q parallel LC circuit. A Crystal Oscillator is an oscillator with the crystal as the feedback element. There are other kinds of oscillators with active or passive feedback comp onen ts, but the crystal oscillator provides the most accurate and stable output freque ncy. Crystal oscillators are the preferred clock source in most high-speed digital systems requiri ng clocks. A chip is a smallpiece of con duct ing material on which an in tegrated circuit is embedded. A microprocessor is a silicon chip that contains a CPU. In operation, acomputer is both hardware and software. One is useless without another. The hardware desig n specifies the comma nds it can follow, and the in structi ons tell it what to do. With the infiltration in the social field of the computer in recent years, the applicati on of the on e-chip computer is moving towards deepe ning con sta ntly, drive traditi on is it measure cresce nt ben efit to upgrade day to con trol at the same time. In measuri ng in real time and automatically con trolled on e-chip computer applicati on system, the one-chip computer often uses as a key part, only one-chip computer respect kno wledge is not eno ugh, should also follow the structure of the con crete hardware , and direct against and use the software of target's characteristic to comb ine con cretely, in order to do perfectly. 译文:微处理器晶体管是电子学发展史上的关键发明之一，它实际上也是人类历史上最重要的发明之一。