The ability to write efficient, high-speed arithmetic routines ultimately depends upon your knowledge of the elements of arithmetic as they exist on a computer. That conclusion and this book are the result of a long and frustrating search for information on writing arithmetic routines for real-time embedded systems. With instruction cycle times coming down and clock rates going up, it would seem that speed is not a problem in writing fast routines. In addition, math coprocessors are becoming more popular and less expensive than ever before and are readily available. These factors make arithmetic easier and faster to use and implement. However, for many of you the systems that you are working on do not include the latest chips or the faster processors. Some of the most widely used microcontrollers used today are not Digital Signal Processors (DSP), but simple eight-bit controllers such as the Intel 8051 or 8048 microprocessors.
标签： arithmetic high-speed ultimately efficient
上传时间： 2014-11-30
上传用户：lizhen9880
This leon3 design is tailored to the Altera NiosII Startix2 Development board, with 16-bit DDR SDRAM and 2 Mbyte of SSRAM. As of this time, the DDR interface only works up to 120 MHz. At 130, DDR data can be read but not written. NOTE: the test bench cannot be simulated with DDR enabled because the Altera pads do not have the correct delay models. * How to program the flash prom with a FPGA programming file 1. Create a hex file of the programming file with Quartus. 2. Convert it to srecord and adjust the load address: objcopy --adjust-vma=0x800000 output_file.hexout -O srec fpga.srec 3. Program the flash memory using grmon: flash erase 0x800000 0xb00000 flash load fpga.srec
标签： Development Startix2 tailored Altera
上传时间： 2014-01-19
上传用户：chongcongying
From the point of view of quality management, it is an important issue to reduce the transmission time in the network. The quickest path problem is to 6ndthe path in the network to senda given amount of data from the source to the sink such that the transmission time is minimized.
标签： transmission management the important
上传时间： 2013-12-19
上传用户：nairui21
IO 驱动 LCD , *** *** *** *** *** *** *** *** FILE NAME: IO_LCD MCU: HT46R22 MASK OPTION: WAKE-UP: PA6,PA7 PULL-HIGH: PA,PB,PC IIC: DISABLE PFD: DISABLE PWM: DISABLE WDT: ENABLE CLRWDT: ONE WDT CLOCK SOURCE: T1 WDT TIME OUT SELECT: WDT CLOCK SOURCE/32768 LVR: DISABLE OSC: CRYSTAL SYSVOLT: 3.0V SYSFRAG: 4000KHZ AUTHOR: RADOME HISTORY: 2005.08.
上传时间： 2014-12-21
上传用户：watch100
Universal Serial Bus (USB) is a communications architecture that gives a personal computer (PC) the ability to interconnect a variety of devices using a simple four- wire cable. The USB is actually a two-wire serial communication link that runs at either 1.5 or 12 megabits per second (mbs). USB protocols can configure devices at startup or when they are plugged in at run time. These devices are broken into various device classes. Each device class defines the common behavior and protocols for devices that serve similar functions. Some examples of USB device classes are shown in the following table
标签： communications architecture Universal computer
上传时间： 2015-12-08
上传用户：stvnash
从结构上来说，实时多任务操作系统包括两部分，一部分为操作系统内核(kernel)，即实时执行程序(Real Time Executive:RTX)，另一部分是输入输出部分(I/O)(注意开发系统不属于操作系统的范畴)；嵌入式系统对I/O的需求通常比较小(无文件系统需求)，因此很多实时多任务操作系统本质上就是一个实时执行程序，如AMX(Kadak)，VRTX(Microtec)，iRMX(Intel)等(这里的X即:eXecutive)，如果纯粹从kernel的角度来考察目前流行的各种实时多任务操作系统的性能，它们的效率差别都不大。 在市面上可以得到一些RTX的源代码(有用C实现的，有用汇编实现的，还有用PL/M语言实现的)，从internet上也可以荡一些下来(我介绍一个站点www.eg3.com，堪称世界电子工程师资源宝库)，下面我要介绍的一个RTX版本(我命名为SRTX:short RTX)，可以说是RTX中的元老级产品了，来自某研究所，九十年代初他们到美国考察，从美国某公司购得。五年以前，SRTX在国内有售，许多搞工控的研究所利用SRTX开发了一些大型或小型的产品,这里介绍的SRTX我作了一些简化和改动.
标签：
上传时间： 2015-12-09
上传用户：wang5829
water temperature control system uses the Single Chip Microcomputer to carry on temperature real-time gathering and controling. DS18B20, digitized temperature sensor, provides the temperature signal by "a main line". In -10～+85℃ the scope, DS18B20’s inherent measuring accuracy is 0.5 ℃. The water temperature real-time control system uses the electricity nichrome wire carring on temperature increiseament and operates the electric fan to realize the temperature decrease control. The system has the higher measuring accuracy and the control precision, it also can complete the elevation of temperature and the temperature decrease control.
标签： temperature Microcomputer real-tim control
上传时间： 2015-12-10
上传用户：nairui21
In a preemptive priority based RTOS, priority inversion problem is among the major sources of deadline violations. Priority inheritance protocol is one of the approaches to reduce priority inversion. Unfortunately, RTOS like uC/OS can’t support priority inheritance protocol since it does not allow kernel to have multiple tasks at the same priority. Although it has different ways to avoid priority inversion such as priority ceiling protocol, developers still have some difficulties in programming real time applications with it. In this paper, we redesign the uC/OS kernel to provide the ability to support round robin scheduling and implement priority inheritance semaphore on the modified kernel. As result, we port new kernel with priority inheritance semaphore to evaluation board, and evaluate the execution time of each of the kernel service as well as verify the operations of our implementation.
标签： priority preemptive inversion problem
上传时间： 2015-12-14
上传用户：气温达上千万的
This application report describes the use of Timer_A3 to decode RC5 and SIRC TV IR remote control signals. The decoder described in this report is interrupt-driven and operates a background function using specific features the Timer_A3. Only a small portion of the MSP430 CPU?s nonreal-time resources is used. Specific hardware bit-latching capabilities of the Timer_A3 module are used for real-time decoding of the IR data signal, independent and asynchronous to the CPU. CPU activity and power consumption are kept to an absolute minimum level. The Timer_A3 decoder implementation also allows other tasks to occur simultaneously if required. The solutions provided are written specifically for MSP430x11x(1) and MSP430x12x derivatives, but can be adapted to any other MSP430 incorporating Timer_A3. 電視遙控器設計基於MSP430
标签： application describes Timer_A control
上传时间： 2014-01-01
上传用户：qq21508895
C++, although a marvelous language, isn t perfect. Matthew Wilson has been working with it for over a decade, and during that time he has found inherent limitations that require skillful workarounds. In this book, he doesn t just tell you what s wrong with C++, but offers practical techniques and tools for writing code that s more robust, flexible, efficient, and maintainable. He shows you how to tame C++ s complexity, cut through its vast array of paradigms, take back control over your code--and get far better results
标签： marvelous although language Matthew
上传时间： 2014-01-22
上传用户：妄想演绎师
