嵌入式系統常用詞匯表

諸葛孔明

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計的硬件。

address bus （地址總線）
A set of electrical lines connected to the processor and all of the peripher
als withwhich itcommunicates. The address bus is used by the processor to select aspecific memory location or register within a particular peripheral. I
f the address bus contains n electrical lines, the processor can uniquely ad
dress up to 2^n such locations.
一個連接處理器與所有外設的，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有不同的應用軟件。

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換到處理器可理解和運行的機器指令的軟件開發工具
。
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。大多數處理器相關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. Typicall
y,sample source code for the board support package is provided by the package developer. The sample code must be modified as necessary, compiled, and li
nked 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 broug
ht 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
理器絕大多數情況下只用在模擬器上，從來不會被特意用在產品系統上。

Breakpoint （斷點）
A location in a program at which execution is to be stopped and control of t
he 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，在那里程序的執行被停止，并且處理器的控制轉換到了除錯程
序。大多數除錯工具提供增加與刪除一個斷點的機制。

C

CISC（復雜指令集計算機）
Complex Instruction Set Computer. Describes the architecture of a processor family. CISC processors generally feature variable-length instructions, mult
iple 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.
   復雜指令集計算機。對一種處理器架構的描述。CISC處理器一般產生變長的指令，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換到只有特定的處理器能了解和執行的機器指令的一種軟件開發
包。

context （上下文）
The current state of the processor"s registers and flags.
處理器當前的狀態和標志。

context switch（上下文切換）
The process of switching from one task to another in a multitasking operatin
g 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.
在多任務操作系統中我一個任務切換到另一個的過程。上下文切換包括保存正在運行的
任務的上下文和恢復早先保存的另一個任務的上下文。做這個工作的一段代碼必須具有
處理器特權。

counting semaphore（計數信號）
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 ava
ilable 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 prod
uces 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，其中之一能產生目標代碼。交叉編譯器在主機上運
行并且產生目標機的目標代碼。

諸葛孔明

D


DMA（直接內存訪問）
Direct Memory Access. A technique for transferring data directly between two peripherals (usually memory and an I/O device) with only minimal interventi
on by the processor. DMA transfers are managed by a third peripheral called a DMA controller.
直接內存訪問。一種直接在兩個外設（通常是內存和I/O設備）之間進行數據傳輸的技術
，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進行管理。


DRAM（動態隨機訪問存儲器）
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 cont
roller.
動態隨機訪問存儲器。一種RAM，存儲在其設備中的數據被定期刷新時才能保存它的內容。刷新周期一般由一個叫DRAM控制器的外設完成。


Data bus（數據總線）
A set of electrical lines connected to the processor and all of the peripher
als with which it communicates. When the processor wants to read (write) the contents of a memory location or register within a particular peripheral, i
t sets the address bus pins appropriately and receives (transmits) the conte
nts on the data bus.
連接處理器與所有外設進行通訊的電子線路集。當一個處理器想去寫（讀）某一特定外
設中的存儲器地址或寄存器中的內容時，處理器設置地址總線并在數據總線上接收（傳
輸）內容。


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。


Deadlock（死鎖）
An unwanted software situation in which an entire set of tasks is blocked, w
aiting for an event that only a task within the same set can cause. If a dea
dlock occurs, the only solution is to reset the hardware. However, it is usu
ally possible to prevent deadlocks altogether by following certain software
design practices.
一種不希望出現的軟件狀態，在這個狀態下，所有的任務因為等待一個只有在這些被阻
塞任務之一才能產生的事件而被阻塞。如果死鎖發生，唯一解決的方法是重啟動硬件。
但是，通過可靠的軟件設計實踐活動通常可以防止死鎖的發生。


debug monitor（除錯監視程序）
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，通過串口或網絡與除錯器進行通訊。除錯監視程序提供一個簡單的命令集來顯示和內存地址和寄存器、建立和移除斷點，并且運行你的程序。除錯監視器組合這些簡單的命令去實現象程序下載各單步調試等高端的請求。


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
通過串口或網絡連接到目標機上。你能使用除錯器下載軟件到目標機并直接運行。你也
可以設置斷點并檢查特定內存地址或寄存器的內容。


device driver（設備驅動程序）
A software module that hides the details of a particular peripheral and prov
ides a high-level programming interface to it.
  一個軟件模塊，它隱藏特定外設的細節并提供高級的外設編程接口。


device programmer（設備編程器）
A  tool for programming non-volatile memories and other electrically-programmable devices. Typically, the programmable device is inserted into a socket on the device programmer and the contents of a memory buffer are then transferred into it.
一種用來對不揮發內存和其他電可編程設備進行編程的工具。典型地，可編程設備被插
到設備編程器的接口上，接著內存緩存器中的內容被傳送到它里面。


digital signal processor（數字信號處理器）
A device that is similar to a microprocessor, except that the internal CPU h
as been optimized for use in applications involving discrete-time signal pro
cessing. In addition to standard microprocessor instructions, DSPs usually s
upport 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備，不同的是它內部的CPU被優化，用于特定的應用，如
離散信號處理。除了標準的微處理器指令外，DSP常常支持復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可以在設備編程器的幫助下被重編程。


embedded system（嵌入式系統）
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合體，或許還加上機械等其他部分，被設計來完成專門的功能
。在一些情況下，嵌入式系統是一個大的系統或產品的一部分，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 incorpora
te 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。一個在你的目標板上放置仿真的處理器的調試工具。仿真器經常
和一目標處理器的一種“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
觀察和記錄它的內部狀態。


Executable（可執行的）
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 de
bugging tool.
   一個包含準備在目標機上運行的目標代碼的文件。放置目標代碼到ROM中或通過調試
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.
是作為目標代碼存貯在ROM中的嵌入式軟件。這個名字在數字信號處理器的用戶中相當流行。


flash memory （閃存）
A RAM-ROM hybrid that can be erased and rewritten under software control. Su
ch devices are divided into blocks, called sectors, that are individually-er
asable. 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據存貯器的地方，一個大容量的閃存甚至被用作磁盤驅動器。

諸葛孔明

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. Contra
st with embedded system.
當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。
HHLLSee 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 delete result in run-time manipulation of the heap.
一塊被用作動態內存分配的內存區域。調用malloc和free、C++的操作符new、delete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。當在高級語言上編程時，不需要考慮特定處理器的細節，只用關心算法和應用。


Host（主機）
A general-purpose computer that communicates with the target via a serial po
rt or network connection. This term is usually used to distinguish the compu
ter on which the debugger is running from the embedded system that is being developed.
一臺通用計算機，它通過串口或網絡連接與目標機通訊。這處名詞一般用來區別調試程
序運行的計算機和被開發的嵌入式系統。


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（輸入）和發光二級管（輸
出）。


I/O device（IO設備）
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備。一般的實例是開關、LED、串口和網絡控制
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.
一張包含每個外設的名字和地址的表格或圖表，可由處理器在I/O空間中設定地址。I/O
映射對得知目標機情況非常有利。


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 ou
t. Contrast with memory space.
一個由處理器提供的特殊內存區域，一般為為I/O設備的附件保留。在I/O空間的內存位
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。相對內存空間而言。


ISR（中斷服務程序）
See interrupt service routine.


instruction pointer（指令指針）
A register in the processor that contains the address of the next instructio
n to be executed. Also known as a program counter.
包含下一條要執行指令地址的處理器中的寄存器。也叫程序計數器。


Interrupt（中斷）
An asynchronous electrical signal from a peripheral to the processor. When t
he peripheral asserts this signal, we say that an interrupt occurs. When an
interrupt occurs, the current state of the processor is saved and an interru
pt service routine is executed. When the interrupt service routine exits, co
ntrol of the processor is returned to whatever part of the software was prev
iously running.
一個從外設到處理器的異步電信號。當外設發出這個信號，我們說一個中斷發生。當一
個中斷發生，當前的處理器狀態被保存并且中斷服務程序開始運行。當中斷服務程序退
出，對處理器的控制權轉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.
在中斷發生和相關的中斷服務程序運行之間的時間長短。


interrupt service routine（中斷服務程序）
A piece of software executed in response to a particular interrupt.
響應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.
和每一個中斷相關聯的唯一數字。


interrupt vector （中斷向量）
The address of an interrupt service routine.
中斷服務程序所在的地址。


interrupt vector table（中斷向量表）
A table containing interrupt vectors and indexed by interrupt type. This tab
le 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.
一種被用來在任務和中斷服務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（內核）
An essential part of any multitasking operating system, the kernel contains
just the scheduler and context-switch routine.
任何多任務操作系統的本質部分，內核僅僅包含調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 a
nd outputs a relocatable program. The linker is thus run after all of the so
urce files have been compiled or assembled.
一種能把一個或更多目標文件組合成可輸入和輸出的可重定位程序的開發工具。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 ca
lled an executable. In some cases, the locator"s function may be hidden with
in 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工具。這是準備一個軟
件在嵌入式系統中運行的最后一步，并且結果文件叫做可執行的。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 a
nalyzers can be quite helpful for debugging hardware problems and complex processor-peripheral interactions.
一種硬件調試工具，能捕獲實時電信號的許多邏輯電平（0或1），邏輯分析儀在調試硬
件問題和復雜的處理外設交互時相當有用。

諸葛孔明

M


memory map（內存映射）


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.
一個在內存空間中的，包含每個外設的名字和可由處理器設置的地址范圍的表格或圖表
。內存映射有助于了解目標機情況。


memory-mapped  I/O（內存映射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計方法，在這種方法中，I/O設備被放置在內存空間而不是I/O空
間。從處理器的觀點看，內存映射I/O設備看上去很象內存一樣。


memory space（內存空間）
A processor"s standard address space. Contrast with I/O space.
一個處理器的標準地址空間。相對I/O空間。


Microcontroller（微控制器）
A microcontroller is very similar to a microprocessor. The main difference i
s that a microcontroller is designed specifically for use in embedded system
s Microcontrollers typically include a CPU, memory (a small amount of RAM an
d/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計用在嵌入式系統中。微控
制器典型地包括CPU、內存（很小的RAM或ROM），還有其他的外設，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 example
s 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，是指調試監視器。然而，第二個意思與任務間通訊相關聯。在那
個上下文中，監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中有多個處理器。被叫作“多處理器系統”的一般有公用的內存空
間，處理器通過它們進行通訊和共享數據。另外，一些多處理器系統支持并行處理。


Multitasking （多任務）
The execution of multiple software routines in pseudo-parallel. Each routine
represents a separate "thread of execution" and is referred to as a task. T
he operating system is responsible for simulating parallelism by parceling o
ut the processor"s time.
偽并行運行的多個軟件程序。每一個程序表現得像分開的“執行的線程”并且被看作是
一個任務。操作系統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 pro
tect critical sections of the code from interruption and shared resources fr
om simultaneous use.
表現互斥現象的數據結構，也被當作二元信號燈。一個互斥基本上是一個多任務敏感的
二元信號，它能用作同步多任務的行為，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 s
et of registers. Mutual exclusion can be achieved with the use of a semaphor
e or mutex.
唯一訪問共享資源的保證。在嵌入式系統中，共享的資源典型的有內存塊或寄存器組。
互斥現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。一種能在系統關機的情況下保持它的數據的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據。編譯器、匯編器、連接器和定位器的輸出文件都含有目標
代碼。


object file（目標文件）
A file containing object code. The output of a compiler or assembler.
包含目標代碼的文件。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.
任一可編程的設備，像PROM，僅僅能被最終用戶編程一次。然而，這個術語一般被專有
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 instruc
tions 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）
A piece of software that makes multitasking possible. An operating system typically consists of a set of function calls, or software interrupts, and a p
eriodic clock tick. The operating system is responsible for deciding which t
ask should be using the processor at a given time and for controlling access
to shared resources.
使多任務能夠實現的一個軟件。一個操作系統典型地由一個函數調用集、軟件中斷和定
期時鐘周期組成。一個操作系統負責決定哪一個任務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 i
f a particular interrupt is currently asserted.
一種硬件調試工具，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
中斷發生，你可以用一個示波器去檢測它。

諸葛孔明

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。能被設備編程器寫的一種ROM。這種內存設備可以被編程一次，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）
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備，常指內存或I/O設備。外設經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。


physical address（物理地址）
The actual address that is placed on the address bus when accessing a memory location or register.

當訪問內存位置或寄存器時，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 sus
pended when a higher-priority task becomes ready. Non-preemptive schedulers are easier to implement but less appropriate for embedded systems.
當一個高優先級的任務準備好時，充許正在運行的任務被掛起的調度策略被稱為優先。
無優先的調度策略更容易實現一些但適合在嵌入式系統中使用。


Polling(輪詢)
A method of interfacing with hardware that involves repeatedly reading a sta
tus 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，不斷讀狀態寄存器，直到設備進入等待狀態。設備驅動程序不是輪
詢的就是中斷驅動的，后一種越來越成為首選的。


Priority（優先）
The relative importance of one task compared to another.
一個任務與其他任務相比的重要關系。


priority inversion（優先轉置）
An unwanted software situation in which a high-priority task is delayed whil
e 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 lowere
d during the delay period.
一種不希望發生的軟件狀態，在此狀態一個高優先級任務因為等待訪問一個那時不再使
用的共享資源而被延遲。在所有的實踐目標中，這個任務的優先級在延遲周期內都被降
低。


Process（進程）
A word that is often confused with task or thread. The crucial distinction i
s 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.
這個名詞經常與任務或線程混淆。至關重要的差別在于系統中的所有任務共享公共的內
存空間。進程，另一方面，常常有它們自己的私有內存空間。進程在多用戶系統中，但
少有地，如有可能，也可在嵌入式系統中。


Processor（處理器）
A generic term that does not distinction between microprocessor, microcontro
ller, and digital signal processor.
一個對于微處理器、微控制器他數字信號處器無差別的通用術語。


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.
一個相關的處理器集，常常連續地從一個生產商產生。例如：Intel"s 80x86族開始從8
086開始，現在有80186, 286, 386, 486, Pentium及其他。在一個族中，稍后的產品典型地向后兼容在它以前生產的產品。


processor-independent（處理器無關）
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 process
or-independent. Contrast with processor-specific.
一個與處理器無關的，并能在其上運行的軟件。大多數用高級語言編寫程序是處理器無
關的。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 wi
ll 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。

諸葛孔明

Profiler（明細觀察程序）
A software development tool that collects and reports execution statistics f
or your programs. These statistics include the number of calls to each subro
utine 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計數據的軟件調試工具。這些統計數據包括調用每個子程序的
次數和用去的時間。這些數據常被用來了解哪些子程序是最關鍵的，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 a
nd/or register windows. The MIPS processor family is an excellent example. C
ontrast 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構，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 writt
en.
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 in
cludes its own serial or network connection to the host.
一種在你的目標板上代替或模擬ROM的調試工具。ROM模擬器動作起來象一個除錯監視器
，除了它包含自己連到主機上的串口或網絡外。
ROM monitor
See debug monitor.

RTOS（實時操作系統）
Real-Time Operating System. An operating system designed specifically for us
e in real-time systems.
實時操作系統。一種被特殊設計來用在實時系統中的操作系統。

race condition（競爭狀態）
A situation in which the outcome of a program may be affected by the exact o
rder in which the instructions are executed. Race conditions are only an iss
ue where interrupts and/or preemption are possible and where critical sectio
ns exist.
一種程序運行的結果可能被指令執行的順序影響的情形。競爭狀態僅僅有一種情況下產
生，在此處中斷或（和）優先搶占是充許的并且有一個臨界區存在。

real-time system（實時系統）
Any computer system, embedded or otherwise, that has deadlines. The followin
g 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, wh
at 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 ge
nerally 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，嵌入的或其他的，有一個死線。以下的問題可經被用來區分實時
系統與其他的系統：“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完成它的工作會發生什么？如果什么也沒有發生，它不是一個實
時系統。如果一些人死或任務失敗，它被認為是“硬”實時系統，意思是系統有一個“
硬”死線。介于兩者之間的是“軟”實時系統。

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.
自己調用自己的程序的說法。遞歸一般在嵌入式系統中是不充許的，因為它常常占有大
量的堆棧空間。

Reentrant（可再入的）
Said of software that can be executed multiple times simultaneously. A reent
rant function can be safely called recursively or from multiple tasks. The k
ey 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。可再入的函數可以被安全地遞歸調用或由多任務多次調
用。使代碼可再入的關鍵在于確保在訪問全局變量或共享寄存器時互斥現象發生。

Register（寄存器）
A memory location that is part of a processor or an I/O device. In other wor
ds, it"s not normal memory. Generally, each bit or set of bits within the re
gister controls some behavior of the larger device.
是處理器或I/O設備一部分的儲存器的地址。換句話說，不是標準的儲存器。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 targ
et. The final step is to use a locator to fix the remaining relocatable addr
esses within the code. The result of that process is an executable.
包含幾乎可以準備好在目標機上運行的目標代碼的文件。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。這個步驟的結果是一個可執行的程序。

諸葛孔明

reset address（重啟地址）
The address from which the first instruction will be fetched after the proce
ssor 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 "j
ump 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簡單，只是
與”跳轉到開始代碼”這樣的意思相同。

reset vector
See reset address.

S

SRAM（靜態隨機訪問儲存器）
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.
靜態隨機訪問儲存器。一種在系統上電時以保持它的內容的儲存器。當系統斷電或重啟
時，保存在SRAM中的內容將丟失。

Scheduler（調度程序）
The part of an operating system that decides which task to run next. This de
cision is based on the readiness of each task, their relative priorities, an
d the specific scheduling algorithm implemented.
操作系統中決定下一次哪個任務運行的那部分。決定基于每一個任務的就緒，它們的優
先級關系，和特殊調度算法的實現。

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據結構。信號燈常常由操作系統提供。

Simulator（仿真器）
A debugging tool that runs on the host and pretends to be the target process
or. A simulator can be used to test pieces of the software before the embedd
ed hardware is available. Unfortunately, attempts to simulate interactions w
ith complex peripherals are often more trouble than they are worth.
一種運行在主機上，裝作目標機處理器的調試工具。仿真器一般用來測試嵌入式硬件可
用之前的軟件。不幸地，與模擬與復雜地外設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. So
ftware interrupts are commonly used to implement breakpoints and operating s
ystem entry points. Unlike true interrupts, they occur synchronously with re
spect to program execution. In other words, software interrupts always occur
at the beginning of an instruction execution cycle.
由軟件指令發起的的一個程序的中斷。軟件中斷被用來實現中斷點他操作系統進入點。
不象真實的中斷，那些中斷在不防礙程序執行時同步發生。換句話說，軟件中斷常常在
指令運行周期的開始發生。

Stack（堆棧）
An area of memory that contains a last-in-first-out queue of storage for par
ameters, automatic variables, return addresses, and other information that m
ust be maintained across function calls. In multitasking situations, each ta
sk generally has its own stack.
一個包含后進先出隊列的內存區域，用來存儲參數、自動變量、返回地址和其他一些必
須在函數調用中進行維護的信息。在多任務情況下，每一個任務一般都有自己的堆棧區
。

stack frame（堆棧幀）
An area of the stack associated with a particular function call.
一個關聯特殊函數調用的堆棧區域。

startup code（啟動代碼）
A piece of assembly language code that prepares the way for software written
in a high-level language. Most C/C++ cross-compilers come with startup code
that you can modify, compile, and link with your embedded programs.
一個匯編語言代碼，它為高級語言寫的軟件準備好運行的前期工作。大多數C/C++交叉編
譯器在你可以修改、編譯他連接你的嵌入式程序時與啟動代碼一起來到。

T

Target（目標機）
Another name for the embedded system. This term is usually used during softw
are development, to distinguish the embedded system from the host with which
it communicates.
嵌入式系統的另一個名字。這個術語常常在軟件開發期間使用，用來區別與嵌入式系統
通訊的主機。

Task（任務）
The central abstraction of an operating system. Each task must maintain its
own copy of the instruction pointer and general-purpose registers. Unlike pr
ocesses, tasks share a common memory space and must be careful to avoid over
writing each other"s code and data.

Thread（線程）
Another name for a task. This name is more common in operating systems that
support processes. A task is simply a thread in a single-process system.

Tracepoint （跟蹤點）
Like a breakpoint except that a counter is incremented rather than stopping
the program. Tracepoints are not supported by all debugging tools.
象中斷點，除了停止程序時，計數器還被增加外。跟蹤點不是被所有的調試工具支持。

Trap（陷入）
An interruption of a program that is triggered by the processor"s own intern
al hardware. For example, the processor might trap if an illegal opcode is f
ound within the program. Compare with software interrupt.
一個由處理器內部硬件觸發的程序中斷。例如，處理器可能在一個錯誤的代碼在程序中
被發現時陷入。對比軟件中斷。

V

volatile（動態）
A value that may change without the intervention of software is said to be v
olatile. For example, values within the registers of some I/O devices may ch
ange in response to external events. C"s volatile keyword should be used to
warn your compiler about any pointers that point to such registers. This wil
l ensure that the actual value is reread each time the data is used.
一個可能不需要軟件的的干涉就可改變的值被叫作動態。例如：在一些I/O設備的寄存器
的值可能在響應外部事件時被改變。C語言中的volatile關鍵字被用來警告你的編譯器那
是一個指向一些寄存器的指針，請不要優化它。這個將確認在數據使用中的每一時間實
際的值是要重新讀入的。

W

watchdog timer（看門狗定時器）
A hardware timer that is periodically reset by software. If the software cra
shesor hangs, the watchdog timer will expire, and the entire system will be
reset automatically.
一種由軟件定時重設的硬件定時器。如果軟件被破壞而掛起，看門狗定時器將超時，整
個系統將自動重啟。