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嵌入式系統(tǒng)常用術(shù)語錦集
嵌入式系統(tǒng)是面向用戶、面向產(chǎn)品、面向應(yīng)用的，它必須與具體應(yīng)用相結(jié)合才會具有生命力、才更具有優(yōu)勢。以下是關(guān)于嵌入式系統(tǒng)常用術(shù)語，希望大家認真閱讀!
A
ASIC(專用集成電路)
Application-Specific Integrated Circuit. A piece of custom-designed hardware in a chip.
專用集成電路。一個在一個芯片上定制設(shè)計的硬件。
address bus (地址總線)
A set of electrical lines connected to the processor and all of the peripherals withwhich itcommunicates. The address bus is used by the processor to select aspecific memory location or register within a particular peripheral. If the address bus contains n electrical lines, the processor can uniquely address up to 2^n such locations.
一個連接處理器與所有外設(shè)的，用來通訊的電子線路集。地址總線被處理器用來選擇在特定外設(shè)中的存儲器地址或寄存器。如果地址總線有n條電子線路，處理器能唯一尋址高達2^n的地址空間。
application software(應(yīng)用軟件)
Describes software modules specific to a particular embedded project. Theapplication software is unlikely to be reusable across embedded platforms, simplybecause each embedded system has a different application.
用來描述一個特定的嵌入式項目中的某一軟件模塊。應(yīng)用軟件不象可重用的交叉嵌入式平臺，只是因為每一個嵌入式系統(tǒng)有不同的應(yīng)用軟件。
assembler(匯編編譯器)
A software development tool that translates human-readable assembly languageprograms into machine-language instructions that the processor can understandand execute.
一個能把人可讀的匯編語言程序轉(zhuǎn)換到處理器可理解和運行的機器指令的軟件開發(fā)工具。
assembly language(匯編語言)
A human-readable form of a processor"s instruction set. Most processor-specific functions must be written in assembly language.
一種人可讀的處理器指令集的形式。大多數(shù)處理器相關(guān)的功能必須用匯編語言編寫。
B
BSP(板卡支持包)
See board support package.
見board support package。
binary semaphore(二元信號)
A type of semaphore with just two states. Also called a mutex.
一種只有兩種狀態(tài)的信號。也叫互斥信號。
board support package(板卡支持包)
Part of a software package that is processor or platform-dependent. Typically,sample source code for the board support package is provided by the package developer. The sample code must be modified as necessary, compiled, and linked with the remainder of the software package.
軟件包的具有平臺依賴性的那一部分。典型地，板卡支持包的樣例源程序由包開發(fā)者提供。樣例源程序必須能在需要時被修改、編譯并與軟件包的剩下的部分連接起來。
bond-out processor (外合處理器)
A special version of a processor that has some of the internal signals brought out to external pins. A bond-out processor is most often found within an emulator and is never intended to be used in a production system.
一種特殊版本的處理器，它有一些，內(nèi)部的信號能傳達到外置的針腳上。一個外合處理器絕大多數(shù)情況下只用在模擬器上，從來不會被特意用在產(chǎn)品系統(tǒng)上。
Breakpoint (斷點)
A location in a program at which execution is to be stopped and control of the processor switched to the debugger. Mechanisms for creating and removing breakpoints are provided by most debugging tools.
一個在程序中的地址，在那里程序的執(zhí)行被停止，并且處理器的控制轉(zhuǎn)換到了除錯程序。大多數(shù)除錯工具提供增加與刪除一個斷點的機制。
C
CISC(復(fù)雜指令集計算機)
Complex Instruction Set Computer. Describes the architecture of a processor family. CISC processors generally feature variable-length instructions, multiple addressing formats, and contain only a small number of general-purpose registers. Intel"s 80x86 family is the quintessential example of CISC. Contrast with RISC.
復(fù)雜指令集計算機。對一種處理器架構(gòu)的描述。CISC處理器一般產(chǎn)生變長的指令，多種地址格式，并且僅僅有少量的通用寄存器。Intel的80x86家族是是典型的CISC處理器。相對于RISC而言。
CPU(中央處理器)
Central Processing Unit. The part of a processor that executes instructions.
中央處理器。處理器中執(zhí)行指令的那一部分。
Compiler(編譯器)
A software development tool that translates high-level language programs into the machine-language instructions that a particular processor can understand and execute.
把高級編程語言程序轉(zhuǎn)換到只有特定的處理器能了解和執(zhí)行的機器指令的一種軟件開發(fā)包。
context (上下文)
The current state of the processor"s registers and flags.
處理器當(dāng)前的狀態(tài)和標(biāo)志。
context switch(上下文切換)
The process of switching from one task to another in a multitasking operating system. A context switch involves saving the context of the running task and restoring the previously-saved context of the other. The piece of code that does this is necessarily processor-specific.
在多任務(wù)操作系統(tǒng)中我一個任務(wù)切換到另一個的過程。上下文切換包括保存正在運行的任務(wù)的上下文和恢復(fù)早先保存的另一個任務(wù)的上下文。做這個工作的一段代碼必須具有處理器特權(quán)。
counting semaphore(計數(shù)信號)
A type of semaphore that is used to track multiple resources of the same type. An attempt to take a counting semaphore is blocked only if all of the available resources are in use. Contrast with binary semaphore.
一種用來跟蹤多個相同類型資源的信號燈。僅僅在所有可用的資源都被用完了時才阻塞。相對二元信號而言。
critical section(臨界段)
A block of code that must be executed in sequence and without interruption to guarantee correct operation of the software. See also race condition.
一段必須按次序執(zhí)行的代碼，并且不能被中斷，否則不能保證軟件正確地操作。參照：競爭狀況。
cross-compiler(交叉編譯器)
A compiler that runs on a different platform than the one for which it produces object code. A cross-compiler runs on a host computer and produces object code for the target.
一個運行在不同的平臺上的編譯器，其中之一能產(chǎn)生目標(biāo)代碼。交叉編譯器在主機上運行并且產(chǎn)生目標(biāo)機的目標(biāo)代碼。
D
DMA(直接內(nèi)存訪問)
Direct Memory Access. A technique for transferring data directly between two peripherals (usually memory and an I/O device) with only minimal intervention by the processor. DMA transfers are managed by a third peripheral called a DMA controller.
直接內(nèi)存訪問。一種直接在兩個外設(shè)(通常是內(nèi)存和I/O設(shè)備)之間進行數(shù)據(jù)傳輸?shù)募夹g(shù)，它只要處理器最少的介入。DMA傳輸由叫DMA控制器的第三方外設(shè)進行管理。
DRAM(動態(tài)隨機訪問存儲器)
Dynamic Random-Access Memory. A type of RAM that maintains its contents only as long as the data stored in the device is refreshed at regular intervals. The refresh cycles are usually performed by a peripheral called a DRAM controller.
動態(tài)隨機訪問存儲器。一種RAM，存儲在其設(shè)備中的數(shù)據(jù)被定期刷新時才能保存它的內(nèi)容。刷新周期一般由一個叫DRAM控制器的外設(shè)完成。
Data bus(數(shù)據(jù)總線)
A set of electrical lines connected to the processor and all of the peripherals with which it communicates. When the processor wants to read (write) the contents of a memory location or register within a particular peripheral, it sets the address bus pins appropriately and receives (transmits) the contents on the data bus.
連接處理器與所有外設(shè)進行通訊的電子線路集。當(dāng)一個處理器想去寫(讀)某一特定外設(shè)中的存儲器地址或寄存器中的內(nèi)容時，處理器設(shè)置地址總線并在數(shù)據(jù)總線上接收(傳輸)內(nèi)容。
Deadline(死線)
The time at which a particular set of computations must be completed. See also real-time system.
一個特定計算必須被完成的時間。請看實時系統(tǒng)。
Deadlock(死鎖)
An unwanted software situation in which an entire set of tasks is blocked, waiting for an event that only a task within the same set can cause. If a deadlock occurs, the only solution is to reset the hardware. However, it is usually possible to prevent deadlocks altogether by following certain software design practices.
一種不希望出現(xiàn)的軟件狀態(tài)，在這個狀態(tài)下，所有的任務(wù)因為等待一個只有在這些被阻塞任務(wù)之一才能產(chǎn)生的事件而被阻塞。如果死鎖發(fā)生，唯一解決的方法是重啟動硬件。但是，通過可靠的軟件設(shè)計實踐活動通�？梢苑乐顾梨i的發(fā)生。
debug monitor(除錯監(jiān)視程序)
A piece of embedded software that has been designed specifically for use as a debugging tool. It usually resides in ROM and communicates with a debugger via a serial port or network connection. The debug monitor provides a set of primitive commands to view and modify memory locations and registers, create and remove breakpoints, and execute your program. The debugger combines these primitives to fulfill higher-level requests like program download and single-step.
嵌入式軟件被特殊設(shè)計來作為除錯工具的一部分。它一般被放在ROM中，通過串口或網(wǎng)絡(luò)與除錯器進行通訊。除錯監(jiān)視程序提供一個簡單的命令集來顯示和內(nèi)存地址和寄存器、建立和移除斷點，并且運行你的程序。除錯監(jiān)視器組合這些簡單的命令去實現(xiàn)象程序下載各單步調(diào)試等高端的請求。
Debugger(除錯器)
A software development tool used to test and debug embedded software. The debugger runs on a host computer and connects to the target through a serial port or network connection. Using a debugger you can download software to the target for immediate execution. You can also set breakpoints and examine the contents of specific memory locations and registers.
一個軟件開發(fā)工具，被用來對嵌入式軟件進行測試和除錯。除錯器在宿主機上運行并且通過串口或網(wǎng)絡(luò)連接到目標(biāo)機上。你能使用除錯器下載軟件到目標(biāo)機并直接運行。你也可以設(shè)置斷點并檢查特定內(nèi)存地址或寄存器的內(nèi)容。
device driver(設(shè)備驅(qū)動程序)
A software module that hides the details of a particular peripheral and provides a high-level programming interface to it.
一個軟件模塊，它隱藏特定外設(shè)的細節(jié)并提供高級的外設(shè)編程接口。
device programmer(設(shè)備編程器)
A tool for programming non-volatile memories and other electrically-programmable devices. Typically, the programmable device is ed into a socket on the device programmer and the contents of a memory buffer are then transferred into it.
一種用來對不揮發(fā)內(nèi)存和其他電可編程設(shè)備進行編程的工具。典型地，可編程設(shè)備插在設(shè)備編程器的接口上，接著內(nèi)存緩存器中的內(nèi)容被傳送到它里面。
digital signal processor(數(shù)字信號處理器)
A device that is similar to a microprocessor, except that the internal CPU has been optimized for use in applications involving discrete-time signal processing. In addition to standard microprocessor instructions, DSPs usually support a set of complex instructions to perform common signal-processing computations quickly.Common DSP families are TI"s 320Cxx and Motorola"s 5600x series.
一種類似于微處理器的的設(shè)備，不同的是它內(nèi)部的CPU被優(yōu)化，用于特定的應(yīng)用，如離散信號處理。除了標(biāo)準(zhǔn)的微處理器指令外，DSP常常支持復(fù)雜指令集去非常快地完成通用的信號處理計算。通用DSP家庭是TI的320Cxx和Motorola的5600x系列。
E
EEPROM(電可擦的，可編程的只讀存儲器)
Electrically Erasable, Programmable Read-Only Memory. (Pronounced"Double-E"-PROM.) A type of ROM that can be erased electronically.
電可擦的，可編程的只讀存儲器。一種ROM能被電擦除。
EPROM(可擦的，可編程的只讀存儲器)
Erasable, Programmable Read-Only Memory. A type of ROM that can be erased by exposing it to ultraviolet light. Once erased, an EPROM can be reprogrammed with the help of a device programmer.
一種可用紫外線擦除的存儲器。一次擦除后，EPROM可以在設(shè)備編程器的幫助下被重編程。
embedded system(嵌入式系統(tǒng))
A combination of computer hardware and software, and perhaps additional mechanical or other parts, designed to perform a dedicated function. In some cases, embedded systems are part of a larger system or product, as is the case of an anti-lock braking system in a car. Contrast with general-purpose computer.
計算機硬件和軟件的結(jié)合體，或許還加上機械等其他部分，被設(shè)計來完成專門的功能。在一些情況下，嵌入式系統(tǒng)是一個大的系統(tǒng)或產(chǎn)品的一部分，就象汽車上的防抱死裝置。與通用計算機相對。
Emulator(仿真器)
Short for In-Circuit Emulator (ICE). A debugging tool that takes the placeof-emulates-the processor on your target board. Emulators frequently incorporate a special "bond-out" version of the target processor that allows you to observe and record its internal state as your program is executing
. 在線仿真器的簡寫。一個在你的目標(biāo)板上放置仿真的處理器的調(diào)試工具。仿真器經(jīng)常和一目標(biāo)處理器的一種“外合”版本合在一起，這個版本的的處理器充許你運行程序時觀察和記錄它的內(nèi)部狀態(tài)。
Executable(可執(zhí)行的)
A file containing object code that is ready for execution on the target. All that remains is to place the object code into a ROM or download it via a debugging tool.
一個包含準(zhǔn)備在目標(biāo)機上運行的目標(biāo)代碼的文件。放置目標(biāo)代碼到ROM中或通過調(diào)試工具下載。
F
Firmware(固件)
Embedded software that is stored as object code within a ROM. This name is most common among the users of digital signal processors.
是作為目標(biāo)代碼存貯在ROM中的嵌入式軟件。這個名字在數(shù)字信號處理器的用戶中相當(dāng)流行。
flash memory (閃存)
A RAM-ROM hybrid that can be erased and rewritten under software control. Such devices are divided into blocks, called sectors, that are individually-erasable. Flash memory is common in systems that require nonvolatile data storage at very low cost. In some cases, a large fash memory may even be used instead of a disk-drive.
一種RAM-ROM的混血兒，它能在軟件的控制下被擦除和重寫。一些設(shè)備被分成叫段組的塊，能個別地可擦。閃存用在需要很便宜的非易失數(shù)據(jù)存貯器的地方，一個大容量的閃存甚至被用作磁盤驅(qū)動器。
G
general-purpose computer(通用計算機)
A combination of computer hardware and software that serves as a
general-purpose computing platform. For example, a personal computer. Contrast with embedded system.
當(dāng)作通用計算平臺的計算機硬件與軟件的組合。例如，PC。相對于嵌入式計算機。
H
HLL
See high-level language.
查閱高級語言。
Heap(堆)
An area of memory that is used for dynamic memory allocation. Calls to malloc and free and the C++ operators new and result in run-time manipulation of the heap.
一塊被用作動態(tài)內(nèi)存分配的內(nèi)存區(qū)域。調(diào)用malloc和free、C++的操作符new、在運行時進行堆的操作。
high-level language(高級語言)
A language, such as C or C++, that is processor-independent. When programming in a high-level language, it is possible to concentrate on algorithms and applications without worrying about the details of a particular processor.
一種語言，象C或C++，是處理器獨立的。當(dāng)在高級語言上編程時，不需要考慮特定處理器的細節(jié)，只用關(guān)心算法和應(yīng)用。
Host(主機)
A general-purpose computer that communicates with the target via a serial port or network connection. This term is usually used to distinguish the computer on which the debugger is running from the embedded system that is being developed.
一臺通用計算機，它通過串口或網(wǎng)絡(luò)連接與目標(biāo)機通訊。這處名詞一般用來區(qū)別調(diào)試程序運行的計算機和被開發(fā)的嵌入式系統(tǒng)。
I
ICE
In-Circuit Emulator. See emulator.
在線仿真器。查閱仿真器。
I/O(輸入/輸出)
Input/Output. The interface between a processor and the world around it. The simplest examples are switches (inputs) and LEDs (outputs).
輸入/輸出。處理器與外界的交互界面。最簡單的例子是開關(guān)(輸入)和發(fā)光二級管(輸出)。
I/O device(IO設(shè)備)
A piece of hardware that interfaces between the processor and the outside world. Common examples are switches and LEDs, serial ports, and network controllers.
一種介于處理器和外界之間的硬件設(shè)備。一般的實例是開關(guān)、LED、串口和網(wǎng)絡(luò)控制器。
I/O map(I/O映射)
A table or diagram containing the name and address range of each peripheral addressable by the processor within the I/O space. I/O maps are a helpful aid in getting to know the target.
一張包含每個外設(shè)的名字和地址的表格或圖表，可由處理器在I/O空間中設(shè)定地址。I/O映射對得知目標(biāo)機情況非常有利。
I/O space(I/O空間)
A special memory region provided by some processors and generally reserved for the attachment of I/O devices. Memory locations and registers within an I/O space can be accessed only via special instructions. For example, processors in the 80x86 family have special I/O space instructions called in and out. Contrast with memory space.
一個由處理器提供的特殊內(nèi)存區(qū)域，一般為為I/O設(shè)備的附件保留。在I/O空間的內(nèi)存位置和寄存器只能通過特殊的指定進行訪問。例如：80X86家族的處理器有叫做in / out的特殊的I/O空間指令。相對內(nèi)存空間而言。
ISR(中斷服務(wù)程序)
See interrupt service routine.
instruction pointer(指令指針)
A register in the processor that contains the address of the next instruction to be executed. Also known as a program counter.
包含下一條要執(zhí)行指令地址的處理器中的寄存器。也叫程序計數(shù)器。
Interrupt(中斷)
An asynchronous electrical signal from a peripheral to the processor. When the peripheral asserts this signal, we say that an interrupt occurs. When an interrupt occurs, the current state of the processor is saved and an interrupt service routine is executed. When the interrupt service routine exits, control of the processor is returned to whatever part of the software was previously running.
一個從外設(shè)到處理器的異步電信號。當(dāng)外設(shè)發(fā)出這個信號，我們說一個中斷發(fā)生。當(dāng)一個中斷發(fā)生，當(dāng)前的處理器狀態(tài)被保存并且中斷服務(wù)程序開始運行。當(dāng)中斷服務(wù)程序退出，對處理器的控制權(quán)轉(zhuǎn)到先前運行的那個軟件上。
interrupt latency(中斷延遲)
The amount of time between the assertion of an interrupt and the start of the associated interrupt service routine.
在中斷發(fā)生和相關(guān)的中斷服務(wù)程序運行之間的時間長短。
interrupt service routine(中斷服務(wù)程序)
A piece of software executed in response to a particular interrupt.
響應(yīng)特定中斷而運行的一小段軟件。
interrupt type(中斷類型)
A unique number associated with each interrupt.
和每一個中斷相關(guān)聯(lián)的唯一數(shù)字。
interrupt vector (中斷向量)
The address of an interrupt service routine.
中斷服務(wù)程序所在的地址。
interrupt vector table(中斷向量表)
A table containing interrupt vectors and indexed by interrupt type. This table contains the processor"s mapping between interrupts and interrupt service routines and must be initialized by the programmer.
一個表格，包含由中斷類型決定的中斷向量和索引。這個表格包含中斷與中斷服務(wù)程序之間的處理器的映射，必須由程序員進行初始化。
intertask communication(進程間通訊)
A mechanism used by tasks and interrupt service routines to share information and synchronize their access to shared resources. The most common building blocks of intertask communication are semaphores and mutexes.
一種被用來在任務(wù)和中斷服務(wù)程序之間共享信息和同步它們對共享資源訪問的機制。大部分進程間通訊的建立的基石是信號燈和互斥。
K
Kernel(內(nèi)核)
An essential part of any multitasking operating system, the kernel contains just the scheduler and context-switch routine.
任何多任務(wù)操作系統(tǒng)的本質(zhì)部分，內(nèi)核僅僅包含調(diào)度程序和上下文切換進程。
L
Linker(連接程序)
A software development tool that accepts one or more object files as input and outputs a relocatable program. The linker is thus run after all of the source files have been compiled or assembled.
一種能把一個或更多目標(biāo)文件組合成可輸入和輸出的可重定位程序的開發(fā)工具。連接程序在所有的源文件都被編譯或匯編之后運行。
Locator(定位程序)
A software development tool that assigns physical addresses to the relocatable program produced by the linker. This is the last step in the preparation of software for execution by an embedded system and the resulting file is called an executable. In some cases, the locator"s function may be hidden within the linker.
一種分配物理地址給連接程序處理過的可重定位程序的軟件開發(fā)工具。這是準(zhǔn)備一個軟件在嵌入式系統(tǒng)中運行的最后一步，并且結(jié)果文件叫做可執(zhí)行的。在一些情況下，定位程序功能隱藏在連接程序中。
logic analyzer(邏輯分析儀)
A hardware debugging tool that can be used to capture the logic levels (0 or 1) of dozens, or even hundreds, of electrical signals in real-time. Logic analyzers can be quite helpful for debugging hardware problems and complex processor-peripheral interactions.
一種硬件調(diào)試工具，能捕獲實時電信號的許多邏輯電平(0或1)，邏輯分析儀在調(diào)試硬件問題和復(fù)雜的處理外設(shè)交互時相當(dāng)有用。
M
memory map(內(nèi)存映射)
A table or diagram containing the name and address range of each peripheral addressable by the processor within the memory space. Memory maps are a helpful aid in getting to know the target.
一個在內(nèi)存空間中的，包含每個外設(shè)的名字和可由處理器設(shè)置的地址范圍的表格或圖表。內(nèi)存映射有助于了解目標(biāo)機情況。
memory-mapped I/O(內(nèi)存映射I/O)
An increasingly common hardware design methodology in which I/O devices are placed into the memory space rather than the I/O space. From the processor"s point of view, memory-mapped I/O devices look very much like memory devices.
一種日益流行的硬件設(shè)計方法，在這種方法中，I/O設(shè)備被放置在內(nèi)存空間而不是I/O空間。從處理器的觀點看，內(nèi)存映射I/O設(shè)備看上去很象內(nèi)存一樣。
memory space(內(nèi)存空間)
A processor"s standard address space. Contrast with I/O space.
一個處理器的標(biāo)準(zhǔn)地址空間。相對I/O空間。
Microcontroller(微控制器)
A microcontroller is very similar to a microprocessor. The main difference is that a microcontroller is designed specifically for use in embedded systems Microcontrollers typically include a CPU, memory (a small amount of RAM and/or ROM), and other peripherals on the same chip. Common examples are the 8051, Intel"s 80196, and Motorola"s 68HCxx series.
微控制器很像微處理器。主要的差別在于微控制器被特殊設(shè)計用在嵌入式系統(tǒng)中。微控制器典型地包括CPU、內(nèi)存(很小的RAM或ROM)，還有其他的外設(shè)，它們在同一塊芯片上。常見的例子是：8051、Intel80196、Motorola68HCxx系列。
Microprocessor(微處理器)
A piece of silicon containing a general-purpose CPU. The most common examples are Intel"s 80x86 and Motorola"s 680x0 families.
一片包含通用CPU的硅片。常見的例子是：Intel80x86、Motorola 680x0系列。
Monitor(監(jiān)視器)
In the context of this book, a debug monitor. However, there is a second meaning for this word that is associated with intertask communication. In that context, a monitor is a language-level synchronization feature.
在這本書的上下文中，是指調(diào)試監(jiān)視器。然而，第二個意思與任務(wù)間通訊相關(guān)聯(lián)。在那個上下文中，監(jiān)視器是高級同步機制的特性。
Multiprocessing(多處理)
The use of more than one processor in a single computer system. So-called "multiprocessor systems" usually have a common memory space through which the processors can communicate and share data. In addition, some multiprocessor systems support parallel processing.
在單個的計算機系統(tǒng)中有多個處理器。被叫作“多處理器系統(tǒng)”的一般有公用的內(nèi)存空間，處理器通過它們進行通訊和共享數(shù)據(jù)。另外，一些多處理器系統(tǒng)支持并行處理。
Multitasking (多任務(wù))
The execution of multiple software routines in pseudo-parallel. Each routine represents a separate "thread of execution" and is referred to as a task. The operating system is responsible for simulating parallelism by parceling out the processor"s time.
偽并行運行的多個軟件程序。每一個程序表現(xiàn)得像分開的“執(zhí)行的線程”并且被看作是一個任務(wù)。操作系統(tǒng)通過分配處理器時間來模擬并行方式。
Mutex(互斥)
A data structure for mutual exclusion, also known as a binary semaphore. A mutex is basically just a multitasking-aware binary flag that can be used to synchronize the activities of multiple tasks. As such, it can be used to protect critical sections of the code from interruption and shared resources from simultaneous use.
表現(xiàn)互斥現(xiàn)象的數(shù)據(jù)結(jié)構(gòu)，也被當(dāng)作二元信號燈。一個互斥基本上是一個多任務(wù)敏感的二元信號，它能用作同步多任務(wù)的行為，它常用作保護從中斷來的臨界段代碼并且在共享同步使用的資源。
mutual exclusion(互斥現(xiàn)象)
A guarantee of exclusive access to a shared resource. In embedded systems, the shared resource is typically a block of memory, a global variable, or a set of registers. Mutual exclusion can be achieved with the use of a semaphore or mutex.
唯一訪問共享資源的保證。在嵌入式系統(tǒng)中，共享的資源典型的有內(nèi)存塊或寄存器組�；コ猬F(xiàn)象能由使用信號燈或互斥完成。
N
NVRAM
Non-Volatile Random-Access Memory. A type of RAM that retains its data even when the system is powered down. NVRAM frequently consists of an SRAM and a long-life battery.
非易失的隨機訪問存儲器。一種能在系統(tǒng)關(guān)機的情況下保持它的數(shù)據(jù)的RAM。NVRAM常常由SRAM和長壽命電池組成。
O
OTP
See one-time programmable.
object code(目標(biāo)代碼)
A set of processor-readable opcodes and data. The output of compilers,assemblers, linkers, and locators are files containing object code.
處理器能讀的操作碼和數(shù)據(jù)。編譯器、匯編器、連接器和定位器的輸出文件都含有目標(biāo)代碼。
object file(目標(biāo)文件)
A file containing object code. The output of a compiler or assembler.
包含目標(biāo)代碼的文件。編譯器或匯編器的輸出。
one-time programmable(一次可編程的)
Any programmable device, like a PROM, that can be programmed just once by the end user. However, this term is used almost exclusively to refer to microcontrollers with on-chip PROM.
任一可編程的設(shè)備，像PROM，僅僅能被最終用戶編程一次。然而，這個術(shù)語一般被專有地使用在擁有片上PROM的微控制器上。
opcode
A sequence of bits that is recognized by the processor as one of the instructions in its instruction set.
一串被處理器驗證過的二進制位的序列，它作為其指令集的一個子集。
operating system(操作系統(tǒng))
A piece of software that makes multitasking possible. An operating system typically consists of a set of function calls, or software interrupts, and a periodic clock tick. The operating system is responsible for deciding which task should be using the processor at a given time and for controlling access to shared resources.
使多任務(wù)能夠?qū)崿F(xiàn)的一個軟件。一個操作系統(tǒng)典型地由一個函數(shù)調(diào)用集、軟件中斷和定期時鐘周期組成。一個操作系統(tǒng)負責(zé)決定哪一個任務(wù)在給定的時間將使用處理器，并且控制對共享資源的訪問。
Oscilloscope(示波器)
A hardware debugging tool that allows you to view the voltage on one or more electrical lines. For example, you might use an oscilloscope to determine if a particular interrupt is currently asserted.
一種硬件調(diào)試工具，它讓你能觀察到一個或更多電路上的電壓。例如：如果一個特殊的中斷發(fā)生，你可以用一個示波器去檢測它。
P
PROM(可編程只讀存儲器)
Programmable Read-Only Memory. A type of ROM that can be written (programmed) with a device programmer. These memory devices can be programmed only once, so they are sometimes referred to as write-once or one-time programmable devices.
可編程只讀存儲器。能被設(shè)備編程器寫的一種ROM。這種內(nèi)存設(shè)備可以被編程一次，所以它們有時被作為寫一次或一次性編程設(shè)備來看待。
parallel processing(并行進程)
The ability to apply two or more processors to a single computation.
一種在單個計算機上運行兩個或多個程序的能力。
Peripheral (外設(shè))
A piece of hardware other than the processor, usually memory or an I/O device. The peripheral may reside within the same chip as the processor, in which case it is called an internal peripheral.
一種不同于處理器的硬件設(shè)備，常指內(nèi)存或I/O設(shè)備。外設(shè)經(jīng)常和處理器在一片芯片上，在這種情況下，它被稱為集成外設(shè)。
physical address(物理地址)
The actual address that is placed on the address bus when accessing a memory location or register.
當(dāng)訪問內(nèi)存位置或寄存器時，在地址總線上的真實的地址。
Preemptive(搶先)
A scheduler is said to be preemptive if it allows the running task to be suspended when a higher-priority task becomes ready. Non-preemptive schedulers are easier to implement but less appropriate for embedded systems.
當(dāng)一個高優(yōu)先級的任務(wù)準(zhǔn)備好時，充許正在運行的任務(wù)被掛起的調(diào)度策略被稱為優(yōu)先。無優(yōu)先的調(diào)度策略更容易實現(xiàn)一些但適合在嵌入式系統(tǒng)中使用。
Polling(輪詢)
A method of interfacing with hardware that involves repeatedly reading a status register until the device has reached the awaited state. Device drivers are either polling or interrupt-driven, with the latter being more generally preferred.
一種硬件交互方法，不斷讀狀態(tài)寄存器，直到設(shè)備進入等待狀態(tài)。設(shè)備驅(qū)動程序不是輪詢的就是中斷驅(qū)動的，后一種越來越成為首選的。
Priority(優(yōu)先)
The relative importance of one task compared to another.
一個任務(wù)與其他任務(wù)相比的重要關(guān)系。
priority inversion(優(yōu)先轉(zhuǎn)置)
An unwanted software situation in which a high-priority task is delayed while waiting for access to a shared resource that is not even being used at the time. For all practical purposes, the priority of this task has been lowered during the delay period.
一種不希望發(fā)生的軟件狀態(tài)，在此狀態(tài)一個高優(yōu)先級任務(wù)因為等待訪問一個那時不再使用的共享資源而被延遲。在所有的實踐目標(biāo)中，這個任務(wù)的優(yōu)先級在延遲周期內(nèi)都被降低。
Process(進程)
A word that is often confused with task or thread. The crucial distinction is that all of the tasks in a system share a common memory space. Processes, on the other hand, always have their own private memory space. Processes are common in multi-user systems but are rarely, if ever, found in embedded systems.
這個名詞經(jīng)常與任務(wù)或線程混淆。至關(guān)重要的差別在于系統(tǒng)中的所有任務(wù)共享公共的內(nèi)存空間。進程，另一方面，常常有它們自己的私有內(nèi)存空間。進程在多用戶系統(tǒng)中，但少有地，如有可能，也可在嵌入式系統(tǒng)中。
Processor(處理器)
A generic term that does not distinction between microprocessor, microcontroller, and digital signal processor.
一個對于微處理器、微控制器他數(shù)字信號處器無差別的通用術(shù)語。
processor family(處理器族)
A set of related processors, usually successive generations from the same manufacturer. For example, Intel"s 80x86 family began with the 8086 and now includes the 80186, 286, 386, 486, Pentium, and many others. The later models in a family are typically backwards-compatible with the ones that came before.
一個相關(guān)的處理器集，常常連續(xù)地從一個生產(chǎn)商產(chǎn)生。例如：Intel"s 80x86族開始從8086開始，現(xiàn)在有80186, 286, 386, 486, Pentium及其他。在一個族中，稍后的產(chǎn)品典型地向后兼容在它以前生產(chǎn)的產(chǎn)品。
processor-independent(處理器無關(guān))
A piece of software that is independent of the processor on which it will be run. Most programs that can be written in a high-level language are processor-independent. Contrast with processor-specific.
一個與處理器無關(guān)的，并能在其上運行的軟件。大多數(shù)用高級語言編寫程序是處理器無關(guān)的。相對于處理器定制。
processor-specific(處理器定制)
A piece of software that is highly dependent on the processor on which it will be run. Such code must usually be written in assembly language. Contrast with processor-independent.
一個高度依賴處理器的軟件，在上其才能運行。一些代碼必須用匯編語言編寫。相對于處理器無關(guān)。
Profiler(明細觀察程序)
A software development tool that collects and reports execution statistics for your programs. These statistics include the number of calls to each subroutine and the total amount of time spent within each. This data can be used to learn which subroutines are the most critical and, therefore, demand the greatest code efficiency.
一種報告你的程序運行統(tǒng)計數(shù)據(jù)的軟件調(diào)試工具。這些統(tǒng)計數(shù)據(jù)包括調(diào)用每個子程序的次數(shù)和用去的時間。這些數(shù)據(jù)常被用來了解哪些子程序是最關(guān)鍵的，并且，由此要求使最好的代碼有效率。
program counter
See instruction pointer.
R
RAM(隨機訪問存儲器)
Random-Access Memory. A broad classification of memory devices that includes all devices in which individual memory locations may be read or written as required.
隨機訪問存儲器。一個包含了所有每個地址能被按需讀寫的存儲設(shè)備的粗略分類。
RISC(精簡指令集計算機)
Reduced Instruction Set Computer. Describes the architecture of a processor family. RISC processors generally feature fixed-length instructions, a load-store memory architecture, and a large number of general-purpose registers and/or register windows. The MIPS processor family is an excellent example. Contrast with CISC.
精簡指令集計算機。一個處理器族的描述。RISC處理器一般的特征是固定長度的指令集，一個負載儲備存儲結(jié)構(gòu)，和大量通用寄存器，及寄存器窗口。MIPS處理器族是極好的例子。相對CISC而言。
ROM(只讀存儲器)
Read-Only Memory. A broad classification of memory devices that includes all devices in which the individual memory locations may be read, but not written.
只讀存儲器。一個包括所的的每個地址只能被讀，不能被寫的存儲器的大概分類。
ROM emulator(ROM模擬器)
A debugging tool that takes the place of-or emulates-the ROM on your target board. A ROM emulator acts very much like a debug monitor, except that it includes its own serial or network connection to the host.
一種在你的目標(biāo)板上代替或模擬ROM的調(diào)試工具。ROM模擬器動作起來象一個除錯監(jiān)視器，除了它包含自己連到主機上的串口或網(wǎng)絡(luò)外。
ROM monitor
See debug monitor.
RTOS(實時操作系統(tǒng))
Real-Time Operating System. An operating system designed specifically for use in real-time systems.
實時操作系統(tǒng)。一種被特殊設(shè)計來用在實時系統(tǒng)中的操作系統(tǒng)。
race condition(競爭狀態(tài))
A situation in which the outcome of a program may be affected by the exact order in which the instructions are executed. Race conditions are only an issue where interrupts and/or preemption are possible and where critical sections exist.
一種程序運行的結(jié)果可能被指令執(zhí)行的順序影響的情形。競爭狀態(tài)僅僅有一種情況下產(chǎn)生，在此處中斷或(和)優(yōu)先搶占是充許的并且有一個臨界區(qū)存在。
real-time system(實時系統(tǒng))
Any computer system, embedded or otherwise, that has deadlines. The following question can be used to distinguish real-time systems from the rest: "Is a late answer as bad, or even worse, than a wrong answer?" In other words, what happens if the computation doesn"t finish in time? If nothing bad happens, it"s not a real-time system. If someone dies or the mission fails, it"s generally considered "hard" real-time, which is meant to imply that the system has "hard" deadlines. Everything in between is "soft" real-time.
任何計算機系統(tǒng)，嵌入的或其他的，有一個死線。以下的問題可經(jīng)被用來區(qū)分實時系統(tǒng)與其他的系統(tǒng)：“是遲到的回答壞，還是一個錯誤的回答壞?”換句話說，如果計算機沒有在指定時間內(nèi)完成它的工作會發(fā)生什么?如果什么也沒有發(fā)生，它不是一個實時系統(tǒng)。如果一些人死或任務(wù)失敗，它被認為是“硬”實時系統(tǒng)，意思是系統(tǒng)有一個“硬”死線。介于兩者之間的是“軟”實時系統(tǒng)。
Recursive(遞歸)
Said of software that calls itself. Recursion should generally be avoided in an embedded system, since it frequently requires a large stack.
自己調(diào)用自己的程序的說法。遞歸一般在嵌入式系統(tǒng)中是不充許的，因為它常常占有大量的堆�？臻g。
Reentrant(可再入的)
Said of software that can be executed multiple times simultaneously. A reentrant function can be safely called recursively or from multiple tasks. The key to making code reentrant is to ensure mutual exclusion whenever accessing global variables or shared registers.
可同時多次運行的程序的說法�？稍偃氲暮瘮�(shù)可以被安全地遞歸調(diào)用或由多任務(wù)多次調(diào)用。使代碼可再入的關(guān)鍵在于確保在訪問全局變量或共享寄存器時互斥現(xiàn)象發(fā)生。
Register(寄存器)
A memory location that is part of a processor or an I/O device. In other words, it"s not normal memory. Generally, each bit or set of bits within the register controls some behavior of the larger device.
是處理器或I/O設(shè)備一部分的儲存器的地址。換句話說，不是標(biāo)準(zhǔn)的儲存器。一般地，在寄存器控制每一二進制位或二進制位的集控制大量設(shè)備的一些行為。
Relocatable(可重定位的)
A file containing object code that is almost ready for execution on the target. The final step is to use a locator to fix the remaining relocatable addresses within the code. The result of that process is an executable.
包含幾乎可以準(zhǔn)備好在目標(biāo)機上運行的目標(biāo)代碼的文件。最后一步是使用定位程序去整理保留在代碼中的可重定位地址。這個步驟的結(jié)果是一個可執(zhí)行的程序。
reset address(重啟地址)
The address from which the first instruction will be fetched after the processor is powered on or reset.
一個處理器上電或重啟后第一個指令能被從之取出來的地址。
reset code(重啟代碼)
A small piece of code that is placed at the reset address. The reset code is usually written in assembly language and may simply be the equivalent of "jump to the startup code."
一段被放置在重啟地址的代碼。重啟代碼一般用匯編語言編寫并且可能相當(dāng)簡單，只是與”跳轉(zhuǎn)到開始代碼”這樣的意思相同。
reset vector
See reset address.
S
SRAM(靜態(tài)隨機訪問儲存器)
Static Random-Access Memory. A type of RAM that retains its contents as long as the system is powered on. Data stored in an SRAM is lost when the system is powered down or reset.
靜態(tài)隨機訪問儲存器。一種在系統(tǒng)上電時以保持它的內(nèi)容的儲存器。當(dāng)系統(tǒng)斷電或重啟時，保存在SRAM中的內(nèi)容將丟失。
Scheduler(調(diào)度程序)
The part of an operating system that decides which task to run next. This decision is based on the readiness of each task, their relative priorities, and the specific scheduling algorithm implemented.
操作系統(tǒng)中決定下一次哪個任務(wù)運行的那部分。決定基于每一個任務(wù)的就緒，它們的優(yōu)先級關(guān)系，和特殊調(diào)度算法的實現(xiàn)。
Semaphore(信號燈)
A data structure that is used for intertask synchronization. Semaphores are usually provided by the operating system.
用于進程間同步的數(shù)據(jù)結(jié)構(gòu)。信號燈常常由操作系統(tǒng)提供。
Simulator(仿真器)
A debugging tool that runs on the host and pretends to be the target processor. A simulator can be used to test pieces of the software before the embedded hardware is available. Unfortunately, attempts to simulate interactions with complex peripherals are often more trouble than they are worth.
一種運行在主機上，裝作目標(biāo)機處理器的調(diào)試工具。仿真器一般用來測試嵌入式硬件可用之前的軟件。不幸地，與模擬與復(fù)雜地外設(shè)進行交互的嘗試常常比它們做到的更差。
software interrupt(軟件中斷)
An interruption of a program that is initiated by a software instruction. Software interrupts are commonly used to implement breakpoints and operating system entry points. Unlike true interrupts, they occur synchronously with respect to program execution. In other words, software interrupts always occur at the beginning of an instruction execution cycle.
由軟件指令發(fā)起的的一個程序的中斷。軟件中斷被用來實現(xiàn)中斷點他操作系統(tǒng)進入點。不象真實的中斷，那些中斷在不防礙程序執(zhí)行時同步發(fā)生。換句話說，軟件中斷常常在指令運行周期的開始發(fā)生。
Stack(堆棧)
An area of memory that contains a last-in-first-out queue of storage for parameters, automatic variables, return addresses, and other information that must be maintained across function calls. In multitasking situations, each task generally has its own stack.
一個包含后進先出隊列的內(nèi)存區(qū)域，用來存儲參數(shù)、自動變量、返回地址和其他一些必須在函數(shù)調(diào)用中進行維護的信息。在多任務(wù)情況下，每一個任務(wù)一般都有自己的堆棧區(qū)。
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