嵌入式系统词汇表

context switch（上下文切换）
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.
在多任务操作系统中我一个任务切换到另一个的过程。上下文切换包括保存正在运行的任务的上下文和恢复早先保存的另一个任务的上下文。做这个工作的一段代码必须具有处理器特权。  

counting semaphore（计数信号）
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.
一种用来跟踪多个相同类型资源的信号灯。仅仅在所有可用的资源都被用完了时才阻塞。相对二元信号而言。  

critical section（临界段）
A block of code that must be executed in sequence and without interruption to guarantee correct operation of the software. See also race condition.
一段必须按次序执行的代码，并且不能被中断，否则不能保证软件正确地操作。参照：竞争状况。  

cross-compiler（交叉编译器）
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.
一个运行在不同的平台上的编译器，其中之一能产生目标代码。交叉编译器在主机上运行并且产生目标机的目标代码。  

D
DMA（直接内存访问）
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.
直接内存访问。一种直接在两个外设（通常是内存和I/O设备）之间进行数据传输的技术，它只要处理器最少的介入。DMA传输由叫DMA控制器的第三方外设进行管理。  

DRAM（动态随机访问存储器）
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.
动态随机访问存储器。一种RAM，存储在其设备中的数据被定期刷新时才能保存它的内容。刷新周期一般由一个叫DRAM控制器的外设完成。  

Data bus（数据总线）
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.
连接处理器与所有外设进行通讯的电子线路集。当一个处理器想去写（读）某一特定外设中的存储器地址或寄存器中的内容时，处理器设置地址总线并在数据总线上接收（传输）内容。  

Deadline（死线）
The time at which a particular set of computations must be completed. See also real-time system.
一个特定计算必须被完成的时间。请看实时系统。  

Deadlock（死锁）
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.
一种不希望出现的软件状态，在这个状态下，所有的任务因为等待一个只有在这些被阻塞任务之一才能产生的事件而被阻塞。如果死锁发生，唯一解决的方法是重启动硬件。但是，通过可靠的软件设计实践活动通常可以防止死锁的发生。  

debug monitor（除错监视程序）
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.
嵌入式软件被特殊设计来作为除错工具的一部分。它一般被放在ROM中，通过串口或网络与除错器进行通讯。除错监视程序提供一个简单的命令集来显示和内存地址和寄存器、建立和移除断点，并且运行你的程序。除错监视器组合这些简单的命令去实现象程序下载各单步调试等高端的请求。  

Debugger（除错器）
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.
一个软件开发工具，被用来对嵌入式软件进行测试和除错。除错器在宿主机上运行并且通过串口或网络连接到目标机上。你能使用除错器下载软件到目标机并直接运行。你也可以设置断点并检查特定内存地址或寄存器的内容。  

device driver（设备驱动程序）
A software module that hides the details of a particular peripheral and provides a high-level programming interface to it.
一个软件模块，它隐藏特定外设的细节并提供高级的外设编程接口。  

device programmer（设备编程器）
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.
一种用来对不挥发内存和其他电可编程设备进行编程的工具。典型地，可编程设备被插到设备编程器的接口上，接着内存缓存器中的内容被传送到它里面。  

digital signal processor（数字信号处理器）
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.
一种类似于微处理器的的设备，不同的是它内部的CPU被优化，用于特定的应用，如离散信号处理。除了标准的微处理器指令外，DSP常常支持复杂指令集去非常快地完成通用的信号处理计算。通用DSP家庭是TI的320Cxx和Motorola的5600x系列。  

E  

EEPROM（电可擦的，可编程的只读存储器）
Electrically Erasable, Programmable Read-Only Memory. (Pronounced"Double-E"-PROM.) A type of ROM that can be erased electronically.
电可擦的，可编程的只读存储器。一种ROM能被电擦除。  

EPROM（可擦的，可编程的只读存储器）
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.
一种可用紫外线擦除的存储器。一次擦除后，EPROM可以在设备编程器的帮助下被重编程。  

embedded system（嵌入式系统）
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.
计算机硬件和软件的结合体，或许还加上机械等其他部分，被设计来完成专门的功能。在一些情况下，嵌入式系统是一个大的系统或产品的一部分，就象汽车上的防抱死装置。与通用计算机相对。  

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
. 在线仿真器的简写。一个在你的目标板上放置仿真的处理器的调试工具。仿真器经常和一目标处理器的一种“外合”版本合在一起，这个版本的的处理器充许你运行程序时观察和记录它的内部状态。  

Executable（可执行的）
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.
一个包含准备在目标机上运行的目标代码的文件。放置目标代码到ROM中或通过调试工具下载。  

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.
是作为目标代码存贮在ROM中的嵌入式软件。这个名字在数字信号处理器的用户中相当流行。  

flash memory （闪存）
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.
一种RAM-ROM的混血儿，它能在软件的控制下被擦除和重写。一些设备被分成叫段组的块，能个别地可擦。闪存用在需要很便宜的非易失数据存贮器的地方，一个大容量的闪存甚至被用作磁盘驱动器。  

G  

general-purpose computer（通用计算机）
A combination of computer hardware and software that serves as a
general-purpose computing platform. For example, a personal computer. Contrast with embedded system.
当作通用计算平台的计算机硬件与软件的组合。例如，PC。相对于嵌入式计算机。