Chapter1 Adder 加法器 A logical circuitused to add two binary numbers. Amplitude 幅度 In a pulse waveform,the height or maximum value of the pulse as measured from its low level . Analog 模拟 Being continuous orhaving continous values. And 与 A basic logicoperation in which a true (HIGH) output occurs only if all the input conditionsare true (HIGH). Binary 二进制 Having two valuesor states ; describes a number system that has a base of two and utiliuzes 1and 0 as its digits. Bit 位 A binary digit,which can be either a 1 or a 0. Bit time 位时间 The interval oftime occupied by a single bit in a sequence of bits; the period of the block. Clock 时钟信号 The baisc timingsignal in a digital system. Data 数据 Information innumeric, alphabetic, or other form. Digital 数字的 Related to digitsor discrete quantities; having a set of discrete values. DIP 双排标准组合封装 Dual-in-linepackage. A type of IC package whose leads must pass through holes to the otherside of a PC board. Frequency 频率 The number of pulsesin one second for a periodic digital waveform. The unit is hertz (Hz). Gate 门电路 A logic circuitthat peforms a specified logic operation such as AND or OR. Input 输入 The signal or linegoing into a circuit. Integratedcircuit (IC) 集成电路 A type of circuitin which all of the components are integrated on a single chip ofsemiconductive material of extremely small size. Invertor 反相器 A NOT circuit; acircuit that changes a HIGH to a LOW or vice versa. Logic 逻辑 In digitalelectronics, the decision-making capability of gate circuits, in which a HIGHrepresents a true statement and a LOW represents a false one. NOT 非 A basic logicoperation that peforms inversions. OR 或 A basic operationin which a true (HIGH) output occurs when one or more of the input conditionsare true(HIGH). Output 输出 The signal or linecoming out of a circuit. Parallel 并行 In digital systems,data occuring simultaneously on several lines; the transfer or processing ofseveral bits simultaneously. Period 周期 The time requiredfor a periodic waveform to repeat itself. Pulse 脉冲 A sudden changefrom one level to another, followed after a time, called the pulse width, by asudden change back to the original level. Serial 串行 Having one elementfollowing another, as in a serial transfer of bits; occuring in sequence afterthan simultaneously. SMT 表面封装技术 Surface-mounttechnology. A category of integrated circuit package having leads that areconnected on the surface of the PC board. Troubleshooting故障检测 The technology or processof systematically identifying, isolating, and correcting a fault in a circuitor system.       Chapter 2 Alphanumeric 字母数字表 Consisting of numbers, letters, and other characters. ASCII 美国信息交换标准码 American standard code for information interchange; themost widely used alphanumeric code. BCD 二－十进位 Binary coded decimal; a digital code in which each of thedecimal digits, 0 through 9, is represented by group of four bits. Byte 字节 A group of eight bits. Carry 进位 The digits generated when the sum of two binary digitsexceeds 1. Complement 反码 The inverse or opposite of a number. Decimal 十进制 Describes a number system with a base of ten. Digit 数字 A symbol used toexpress a quantity. Exponent 指数，幂 The part of a floating-point number that represents thenumber of places that the decimal point (or binary point) is to be moved. Floating-point number 浮点数 A number representation based on scientific notation inwhich the number consists of an exponent and a mantissa. Gray code 格雷码 An unweigthed digital code characterized by a single bitchange between adjacent code number in a sequence. Hexadecimal 十六进制 Describes a number system with a base of 16. Integer 整数 A whole number. Least significant bit (LSB) 最低有效位 Generally, the right-most bit in a binary whole number orcode. Mantissa 尾数 The magnitude of a floating-point number. Most significant bit (MSB) 最高有效位 The left-most bit in a binary whole number or code. Octal 八进制 Describes a number system with a base of 8. Overflow 溢出 The condition that occurs when the number of bits in asum exceeds the number of bits in each of the numbers added. Parity 奇偶校验 In relation to binary codes, the condition of evenness oroddness of the number of 1s in a code group. Sign bit 符号位 The left-most bit of a binary number the designateswhether the number is positive (0) or negative(1) . Weight 权值 The value of a dight in a number based on its position inthe nubmer.       Chapter3 AND gate 与门 A logic gate thatproduces a HIGH ouput only when all of the inputs are HIGH. ANSI 美国国家标准协会 American NationalStandard Institute. Booleanaddition 布尔加法 In Boolean algebra,the OR operation. Booleanalgebra 布尔代数 The mathematics oflogic circuits. Booleanmultilplication 布尔乘法 In Boolean algebra,the AND operation. CMOS 互补性金属氧化半导体 Complementarymetal-oxide semiconductor; a class of integrated logic circuit that isimplemented with a type of field-effect transistor. ECL发射极耦合逻辑 Emitter-coupledlogic; a class of integrated logic circuit that is implemented with nonsaturatingbipolar junction transistors. Enable 使能 To activate or putinto an operational mode; an input on a logic circuit that enables itsoperation. Exclusive-NOR(XNOR)gate 同或门 A logic gate thatproduces a LOW output only when its two inputs are at opposite levels. Exclusive-OR(XOR)gate 异或门 A logic gate thatproduces a HIGH output only when its two inputs are at opposite levels. Fan-out 扇出 The number ofequivalent gate inputs of the same family series that a logic gate can drive. IEEE 电子电气工程师协会 Institute ofElectrical and Electronic Engineers. Inversion 反转 The conversion of aHIGH(1) level to a LOW(0) level or vice versa. NAND gate 与非门 A logic gate whichproduces a LOW output only when all the inputs are HIGH. Negative-AND非与 An equivalent NORgate operation in which the HIGH is the active output when all inputs are LOW. Negative-OR 非或 An equivalent NANDgate operation in which the HIGH is the active input when one or more of theinputs are LOW. NOR gate 或非门 A logic gate inwhich the output is LOW when one or more of the inputs are HIGH. OR gate 或门 A logic gate thatproduces a HIGH output when one or more inputs are HIGH. Powerdissipation 功耗 The product of thedc supply voltage and the dc supply current in an electronic circuit; the amountof power required by a circuit. Prapagationdelay time 传播延迟时间 The time intervalbetween the occurrence of an input transition and the occurrence of thecorresponding output transition in a logic circuit. Speed-powerproduct 速度－功率乘积 A performanceparameter that is the product of the propagation delay time and the powerdissipation in a logic circuit. Truth table 真值表 A table showing theinputs and corresponding output(s) of a logic circuit. TTL 电晶体-电晶体逻辑电路 Transistor-tarnsistorlogic; a class of integrated logic circuit that uses bipolar junctiontransistors. Unit load 单位负载 A measure offan-out. One gate input represents one unit load th the output of a gate withinthe same IC family.     Chapter4 Adjacency 邻接 Characteristic ofcells in a Karnaugh map in which there is a single-variable change from onecell to another cell next to it on any of its four sides. Associativelaw 结合律 In addition(ORing)and multiplication(ANDing) of three or more variables, the order in which thevariables are grounded makes no difference. Booleanexpression 布尔表达式 An arrangment ofvariables anf logical operators used to express the operation of a logiccircuit. Cell 单元 An area on aKarnaugh map that represents a unique combiantion of variables in product form. Commutativelaw 交换律 In addition (ORing)and multiplication (ANDing) of two variables, the order in which the variablesare ORed or ANDed makes no difference. Distributivelaw 分配律 ORing severalvariables and then ANDing the result with a single variable is equivalent toANDing the single variable with each of several variables and then ORing theproducts. Domain 域 All of thevariables in a Boolean expression. “Don’t care”任意值 A combination ofinput literals that cannot occur and can be used as a 1 or a 0 on a Karnaughtmap. Karnaughtmap 卡诺图 An arrangment ofcells representing the combination of literals in a Boolean expression and usedfor a systematic simplification of the expression. Literal 实字 A variable or thecomplement of a variable.c Product-of-sum(POS) 和之积 A form of Booleanexpression that is basically the ANDing of ORed terms. Product term乘积项 The Boolean productof two or more literals equivalent to an AND operation. Sum-of-products积之和 A form of Booleanexpression that is basically the ORing if ANDed terms. Sum term 和项 The boolean sum oftwo or more literals equivalent to an OR operation. Variable 变量 A symbol used torepresent a logical quantity that can have a value of 1 or 0, usuallydesignated by an italic letter.     Chapter5 Dual symbols双分符号 The negative-AND isthe dual symbol for the NOR gate, and the negative-OR is the dual symbol forthe NAND gate. Node 节点 A common connectionpoint in a circuit in which a gate output is connected to one or more gateinputs. Signaltracing 信号故障追踪 A troubleshootingtechnique in which waveforms are observed in a step-by-step manner beginging atthe input and working toward the output or vice versa. At each point theobserved waeform is compared with the correct signal for that point. Universalgate 通用门电路 Either a NAND gateor a NOR gate. The term universal refers to the property of a gate that permitsany logic function to be implemented by that gate or by a combination if gatesof that kind.     Chapter6 Carrygeneration 进位产生 The process ofproducing an output carry in a full-adder when both input bits are 1s. Carrypropagation进位传送 The process ofrippling an input carry to become an output carry in a full-adder when eitherof both of the input bits are 1s and the input carry is a 1. Cascading级联 Connecting theoutput of one device to the input of a similar device, allowing one device todrive another in order to expand the operational capability. Codeconverter代码转换器 A digital devicethat converts one type of coded information into another coded form. Dataselector数据选择器 A circuit thatselects data from several inputs one at a time in a sequence and place them onthe output; also called a multiplexer. Decoder解码器 A digital circuitthat converts coded information into a familiar of noncoded form. demultiplexer(DEMUX)数据分配器 A circuit thatswitches digital data from several input lines onto a single output line in aspecified time sequence. Dependencynotation关联标注 A notational systemfor logic symbols that specifies input and output relationships, thus fullydefining a given function; an integral part of ANSI/IEEE Std. 91-1984. Encoder译码器 A digital circuitthat conv3erts information to a coded form. Even parity偶校验 The condition ofhaving an even number of 1s in every group of bits. Full-adder全加器 A digital circuitthat adds two bits and an input carry to produce a sum and an output carry. Glitch. 干扰脉冲 A voltage orcurrent spie of short duration, usually unintentionally produced and unwanted. Half-adder半加器 A digital circuitthat adds two bits and produces a sum and an output carry.? Ir cannot handleinput carries. Look-aheadcarry超前进位 A method of binaryaddition whereby carries from preceding adder stages are anticipated, thuselimination carry propagation delays. Multiplexer(MUX)多路(复用)器 A circuit thatswitches digital data from several input lines onto a single output line in aspecified time sequence. Nibble半字节 A group of fourbits. Odd parity奇校验 The condition ofhaving an odd number of 1s in every group of bits. Parity bit校验位 A bit attached toeach group of information bits to make the total number of 1s odd or even forevery group of bits. Priorityencoder优先编码器 An encoder in whichonly the highest value input digit is encoded and any other active input is ignored. Pull-upresistor上拉电阻 A resistor with oneend connected to the dc supply voltage used to keep a given point in a circuitHIGH when in the inactive state. Ripplecarry.串行进位 A method of binaryaddition in which the output carry from each adder becomes the input carry ofthe next higher-order adder. Strobing选通 A process of usinga pulse to sample the occurrence of an evernt at a specified time in relationto the event. Zerosuppression消零 The process ofblanking out leading or trailing zeros in a digital display.     Chapter7 ABEL高级布尔表达式语言 Advanced BooleanExpression Language. A software compiler language for PLD programming; A typeof hardware description language(HDL). Architecture结构 The internalfunctional arrangement of the elements that give a device its particularoperating characteristics. Array列阵 In a PLD, a matrixformed by rows of product-term lines and columns of input lines with aprogrammable cell at each junction. Buffer缓冲器 A circuit thatprevents loading of an input or output. Cell单元 A fused corss pointof a row and column in a PLD. Compiler编译器 Software thattranslates from high-level language that uses words of symbols, such as ABEL orCUPL, into low-level machine language(1s and 0s) Documentation文档文件 The information forma computer that documents the final design after the input file has beenprocessed. E2CMOS电可擦除的互补金属氧化物半导体 Electricallyerasable COMS(EECMOS). The circuit technology used for the reprogrammable cellsin a GAL. Fuse熔丝 The programmableoutput logic macrocells. GAL通用陈列逻辑 Generic arraylogic. A PLD with a reprogrammable AND array, a fixed OR array, andprogrammable output logic macrocells. Input file输入文件 The informationentered in computer that describes a logic design using a PLD programminglanguage such as ABEL or CUPL. Input.Output(I/O)输入/输出 A terminal ofdevice that can be used as either an input of as an output. JEDEC file电子工程设计发展联合会议文件 A Joint ElectronicDevice Engineering Council standard software file generated from the compilersoftware that is used by a programming device to implement a logic design in aPLD; also called a fuse map of cell map. OLMC输出逻辑宏单元 Output logicmacrocell. The programmable output logic in a GAL. PAL可编程阵列逻辑 Programmable arraylogic. A PLD with a programmable AND array and a fixed or array. PLA可编程逻辑阵列 Programmable logicarray. A PLD with programmable AND and OR arrays. Programmer程序编辑器 An instrument thatprograms a PLD using a JEDEC file downloaded from a computer running hardwaredescription language software. PROM可编程只读存储器 Programmableread-only semiconductor memory. A PLD with a fixed AND array and programmableOR array; used as a memory device and normally not as a logic circuit device. Software软件 Computer programs;programs that instruct a computer what to do in order to carry out a given setof tasks. Synthesis综合 The softwareprocess of converting a circuit description to a standard JEDEC file for PLDprogramming. Tristateoutput buffer三态输出缓冲器 A logic circuithaving three output states: HIGH, LOW, and high impedance(open). ZIF socketZIP插座 Zero insertionforce socket. A type of socket used in most programmers that accepts a PLDpackage.     Chapter8 Astable 非稳态的 Having no stablestate. An astable multivibrator oscillates between two qusaistable states. Asynchronous异步的 Having no fixedtime relationship. Bistable双稳态的 Having two stablestates. Flip-flops and latches are bistable multivibrators. Clear清零 An asynchronousinput used to reset a flip-flop (make the Q output 0). D flip-flopD触发器 A type of bistablemultivibrator in which the output assumes the state of the D input on thetriggering edge of a clock pulse Edge-triggeredflip-flop边缘触发器 A type of flip-flopin which the data are entered and appear on the output on the same clock edge. Feedback反馈 The output voltageor a portion of it that is connected back to the input of circuit. Hold time保持时间 The time intervalrequired for the control levels to remain on the inputs to a flip-flop afterthe triggering edge of the clock in order to reliably activate the device. Hysteresis滞后作用 A characteristic ofthreshold-triggered circuit, such as the Schmitt trigger, where the deviceturns on and off at different input levels. J-Kflip-flop J-k触发器 A type of flip-flopthat can operate in the SET, RESET, no-change, and toggle modes. Latch锁存器 A bistable digitalcircuit used for storing a bit. Master-slaveflip-flop主从触发器 A type of flip-flopin which the input data are entered into the device on the leading edges ofclock pulses and appear at the output on trailing edges. Master-slave flip-flophave, for the most part, been replaced by edge-triggered types. Monostable单稳态的 Having only onestable state. A monostable multivibrator, commonly called a one-shot, producesa single pulse in response to a triggering input. One-shot单稳态触发器 A monostablemultivibrator. Preset预置 An asynchronousinput used to set a flip-flop(make the Q output 1) RESET复位/dt> The state of aflip-flop or latch when the output is 0; the action of producing a RESET state. SET置位 The state offlip-flop of latch when the output is 1; the action of producing a SET state. Set-up time设置时间 A SET-RESETflip-flop. Timer计时器 A circuit that canbe used as a one-shot or as an oscillator. Toggle触发 The action of aflip-flop when it changes state on each clock pulse.     Chapter9 Asynchronouscounter异步计数器 A type of counterin which each stage is clocked from the output of the preceding stage. Cascade级联 To connect“end-to-end” as when several counters are connected from the terminal countoutput of one counter to the enable input of the next counter. Decade十进制 Characterized byten states or values. Decadecounter十进制计数器 A digital counterhaving ten states. Recycle循环 To undergotransition (as in a counter) from the final or terminal state back to theinitial state. Ripplecounter脉动计数器 An asynchronouscounter. Sequentialcircuit时序电路 A digital circuitwhose logic states follow on specified time sequence. Statediagram状态图 A graphic depictionof a sequence of states or values. Statemachine状态机 A logic systemexhibiting a sequence of states conditioned by internal logic and externalinputs; any sequential circuit exhibiting a specified sequence of states. Synchronouscounter同步计数器 A type of counterin which each stage is clocked b the same pulse. Terminalcount最终计数 The final state ina counter’s sequence. Truncated截断 Shortened. Truncatedsequence截取序列 A sequence thatdoes not include all of the possible states of a counter. Up/Downcounter上行/下行计数器 A counter that canprogress in either direction through a certain sequence.     Chapter10 Bidirectional双向的 Having twodirections. In a bidirectional shift register, the stored data can be shiftedright or left. Johnsoncounter Johnson计数器 A type of registerin which a specific prestored pattern of 1s and 0s is shifted through thestates, creating a unique sequence of bit patterns. Load加载 To enter data intoa shift register. Ring counter环形计数器 A register in whicha certain pattern of 1s and 0s continuously recirculated. Shift移位 To move binary datafrom state to stage within a shift register of other storage device or to movebinary data into or out of the device. Stage层 One storage elementin a register. Universalshift register通用移位寄存器 A register that has both serial and parallel input andoutput capability.       Chapter11 Global cell全局单元 A programmable cellin a PLD array that affects all of the OLMCs when programmed. Local cell本地单元 A programmable cellin a PLD array that affects individual OLMCs when programmed. Registered 寄存器模式 A PLD outputconfiguration where the output comes from a flip-flop.     Chapter12 Access time存取时间 The time from theapplication of a valid memory address to the appearance of valid output data. Address地址 The location of agiven storage cell or group of cells in a memory. BEDO DRAM脉冲扩展数据输出动态随机访问存储器 Burst extended dataoutput dynamic random-access memory. Bus 总线 Asset ofinterconnections that interface one or more devices based on a standardizedspecification. Byte字节 A group of eightbits. Cache memory高速缓冲存储器 A relatively small,high-speed memory that stores the most recently used instructions or data fromthe larger but slower main memory. Capacity容量 The total number ofdata units(bits, nibbles, bytes, words) that a memory can store. CCD电荷耦合器件 Charge-coupleddevice; a type of semiconductor memory that stores data in te form of chargepackets and is serially accessed. CD-R可记录光盘 CD-Recordable; anoptical disk storage device on which a data can be stored once. CD-ROM光盘 An optical diskstorage device on which data is prestored. CD-RW可重写光盘 CD-Rewritable; anoptical disk storage on which data can be written and over-written many times. Cell单元 A single storageelement in a memory. DAT数码录音带 Digital audio tape;a type of magnetic tape format. DIMM双列直插内存模块 Dual in-line memorymodule. DLT数字线性磁带 Digital lineartape; a type of magnetic tape format. DRAM动态随机存储器 Dynamicrandom-access memory; a type of semiconductor memory that uses capacitors asthe storage elements and is a volatile, read/write memory. DVD-ROM数字通用磁盘（数字视频磁盘） Digital versatiledisk-ROM; also known as digital video disk-ROM; a type of optical storagedevice on which data is restored with a much higher capacity than a CD-ROM. Dynamicmemory动态存储器 A type ofsemiconductor memory having capacitive storage cells that lose stored data overa period of time and, therefore, must be refreshed. EDO DRAM扩展数据输出动态随机存取记忆体 Extended dataoutput dynamic random-access memory. EEPROM电可擦除只读存储器 Electricallyerasable programmable read-only memory; a type of semiconductor memory device. EPROM可擦写可编程只读存储器 Erasableprogrammable read-only memory; a type of semiconductor memory device thattypically uses ultraviolet light to erase data. FET场效应管 Field-effecttransistor. FIFO先入先出 First in –first outmemory. Flash memory闪存 A nonvolatileread/write random-access semiconductor memory in which data is stored as chargeon the floating gate of a certain type of FET. Floppy disk软盘 A magnetic storagedevice; a flexible disk with a diameter of 3.5 inches and a storage capacity of1.44 Mbytes encased in a rigid plastic housing. FPM DRAM快页模式的动态随机存储器 Fast page modedynamic random-access memory. Hard disk硬盘 A magnetic storagedevice; typically, a stack of two or more rigid disks enclosed in a sealedhousing. Jazcartridge JAZ磁带 A magnetic storagedevice; hard disks encased in a rigid plastic cartridge with storage capacitiesof 1 Gbyte or 2 Gbytes. Latencyperiod等待时间 The time it takesfor the desired sector to spin under the head once the head is positioned overthe desired track of a magnetic hard disk. LIFO后入先出 Last in-first outmemory; a memory stack. Magneto-Opticaldisk光学磁盘 A storage devicethat uses both electromagnetism and a laser beam to read and write data. Memory array存储器阵列 An array of memorycells arranged in rows and columns. MOSFET金属氧化物半导体场效应晶体管 Metal-oxidesemiconductor field-effect transistor. Nibble 半字节 A group of fourbits. Nonvolatile非易失性 A term thatdescribes a memory that can retain stored data when the power is removed. Pipeline 流水线技术 As applied tomemories, an implementation that allows a read or write operation to beinitiated before the previous operation is completed. PROM可编程只读存储器 Programmableread-only memory; a type of semiconductor memory. QIC 1/4英寸磁带 Quarter-inchcassette; a type of magnetic tape. RAM随机存取存储器 Random-accessmemory; a volatile read/write semiconductor memory. Read读取 The process ofretrieving data from a memory. Refresh刷新 To renew thecontents of a dynamic memory by recharging the capacitor storage cells. ROM只读存储器 Read-only memory; anonvolatile random-access semiconductor memory. Seek time寻道时间 The time for theread/write head in a hard drive to position itself over the desired track for aread operation. SDRAM同步动态随机存储器 Synchronous dynamicrandom-access memory. SIMM单线存储器模块 Single in-linememory module. SRAM静态随机访问存储器 Staticrandom-access memory; atype of volatile read/write semiconductor memory. Staticmemory静态存储器 A volatilesemiconductor memory that uses flip-flops as the storage cells and is capableof retaining data without refreshing. UV PROM紫外线可擦写可编程ROM Ultravioleterasable programmable ROM. Volatile易失存储器 A term thatdescribes a memory that loses its stored data when the power is removed. Word字 A complete unit ofbinary data. Wordcapacity字容量 The number of wordthat a memory can store. Word length字长 The number of bitsin a word. WORM只写一次存储器 Write once-readmemory; a type of optical storage device. Write写 The process ofstoring data in a memory. Zip disk Zip磁盘 A type of magneticstorage; a flexible disk with a capacity of 100 Mbytes housed in a rigidplastic cartridge about the size of a floppy.     Chapter13 Acceptor接收器 A receiving deviceon a bus. Analog-to-digitalconverter (ADC)模数转换器 A device used toconvert an analog signal to digital form. Bus总线 A set ofinterconnections that interface one or more devices based on a standardizedspecification. Busarbitration总线仲裁 The process thatprevents two sources from using a bus at the same time. Bus contention总线竞争 An adversecondition that could occur if two or more devices try to communicate at thesame time on a bus. Controller控制器 An instrument thatcan specify each of the other instruments on the bus as either a talker or alistener for the purpose of data transfer. DCE数据通信设备 Data communicationsequipment. Digital-to-analogconverter (DAC)数模转换器 A device used toconvert a digital input to an analog signal. DTE数据终端设备 Data terminalequipment. Flash ADC A simultaneousanalog-to-digital converter. GPIB通用接口总线 General-purposeinterface bus based on the IEEE 488 standard. Handshaking握手协议 The process ofsignal interchange by which two digital devices or systems jointly establishcommunication. High-Z高阻态 The high-impedancestate of a tristate circuit in which the output is effectively disconnectedfrom the rest of the circuit. IEEE 488 busIEEE 488总线 Same as the GPIB. Astandard parallel bus used widely for test and measurement interfacing. IEEE 1394bus IEEE 1394总线 A serial bus forhigh-speed data transfer; also known as FireWire. Interfacing接口 The process ofmaking two or more electronic devices or systems operationally compatible witheach other so that they can function properly together. ISA bus ISA总线 Industry standardarchitecture bus; an internal parallel bus standard. Listener收话器 An instrumentcapable of receiving data on a GPIB. Local bus本地总线 An internal busthat connects the microprocessor to the cache memory, the main memory, thecoprocessor, and the PCI bus controller. Modem调制解调器 Amodulator/demodulator for interfacing digital devices to analog transmissionsystems such as telephone lines. Monotonicity单调性 The characteristicof a DAC defined by the absence of any incorrect step reversals; one type ofdigital-to-anolog linearity. PCI bus PCI总线 Peripheral controlinterconnect bus; an internal parallel bus standard. Peripheral外围设备 A device orinstrument that provides communication with a computer or provides auxiliaryservices or functions for a computer. Port端口 The physicalinterface between a computer and a peripheral. SCSI小型计算机系统接口 Small computersystem interface; an external parallel bus standard. Source源 A sending device ona bus. Talker 发话器 An instrumentcapable of transmitting data on a GPIB. Tristate 三态 A type of output inlogic circuits that exhibits three states; HIGH, LOW, and High-Z. USB通用接口总线 Universal serialbus; an external serial bus standard.     Chapter14 Accumulator累加器 A general-purposeregister used for arithmetic and logic operations. Address地址 A unique memorylocation containing one byte. Address bus地址总线 Generally, aone-way group of conductors from the microprocessor to memory, containing theaddress information. ALU算术逻辑单元 Arithmetic logicunit; the portion of the CPU that interfaces with the system buses and fetchesinstructions, reads operands, and writes results. Compiler编译器 A program thattranslates high-level program statements, such as BASIC, Pascal, or Fortran,into machine language. Contiguous邻接 Joined together. Control bus控制总线 A one-way set ofconductors that connects the CPU to other parts of the computer to coordinateits operations and to communicated with external devices. Control unit控制单元 The portion withinthe microprocessor that provides the timing an control signals for getting datainto and out of the microprocessor and for synchronizing the execution ofinstructions. Coprocessor协处理器 A microprocessordesigned with a limited instruction set optimized to perform arithmeticoperations very quickly; it generally works I conjunction with ageneral-purpose microprocessor. CPU 中央处理单元 Central processingunit(also called the MPU); the main part of a computer responsible for controland processing of data. Data bus数据总线 A bidirectional setof conductive paths on which data or instruction codes are transferred into themicroprocessor or on which the result of an operation or computation is sentout from the microprocessor. Debug调试工具 A code within DOSthat allows various operations on files. It includes a primitive assembler. DMA直接存储器存取 Direct memoryaccess; a method to directly interface a peripheral device to memory witherusing the CPU for control. EU执行单位 Execution unit; theportion of a CPU that executes instructions; it contains the arithmetic logicunit (ALU), the general registers, and the flags. Flag标志 A bit thatindicates the result of an arithmetic or logic operation or is used to alter anoperation. Hardware硬件 The circuitry andphysical components of a computer system (as opposed to the directions calledsoftware). Instructionpairing指令配对 The process ofcombining certain independent instructions so that they can be executedsimultaneously by two separate execution units. Interrupt中断 A signal orinstruction that caused the current process to be temporarily stopped while aservice routine is run. I/O port输入输出端口 Input/output port;the interface between an tinernal bus and a peripheral. IP指令指针 Instructionpointer; a special register within the CPU that holds the offset address of thenext instruction to be executed. Machine code机器码 The basic binaryinstructions understood by the processor. Memory-mappedI/O存储器映像I/O A method ofaddressing ports by assigning addresses within the computer memory addressspace to the por. The CPU views the I/O ports as memory locations. Microcontroller微控制器 A specializedmicroprocessor designed for control functions. Microprocessor微处理器 A digitalintegrated circuit device that can be programmed with a series of instructionsot perform specified function on data. Mnemonic助记符 An English-likeinstruction that is converted by an assembler into a machine code for use by aprocessor. Multitasking多任务 An operating systemenvironment in which the computer seems to run multiple programs or taskssimultaneously. Op-code操作码 The code for aninstruction; a mnemonic. Operand操作符 A variable, aregister, a memory location, or a value used in an assembly language program aspart of the instruction. PIC可编程中断控制器 Programmableinterrupt controller; handles the interrupts on a priority basis. Pointer指针 The contents of aregister (or registers) that contain an address. Polling轮询 The process ofchecking a series of peripheral devices to determine if any require servicefrom the CPU. Port端口 A physicalinterface on a computer through which data are passed to or from peripherals. PPI可编程外围接口 Programmableperipheral interface; a special IC used to implement I/O ports. Prefetching预取 The process ofexecuting instruction at the same time as other instructions are “fetched,”eliminating idle time; also called pipelining. Program程序 A group ofinstructions designed to solve a specific problem. Pseudo-operation伪操作 An instruction tothe assembler (as opposed to a processor). Queue对列 A high-speed memorythat stores instructions or data. Real mode