Keil 自带的 RTX51—tiny 系统有这样几个缺点:1、非占先式任 务调度,这样系统的实时性就很难保证 2、提供的系统服务太少, 只有 wait 与 signal。而 RTX51—tiny 的优点是:1、Keil 公司自己开 发的,使用_task_关键字区别每个任务,这样可以使得被不同任务调 用的不同函数即使没有相互调用,他们的局部变量也不会相互覆盖。 免去了在 SmallRTOS 中需要手动制止函数间局部变量的相互覆盖。 2、内核小。整个 RTX51--tiny 完整编译只需 900B 的空间。
上传时间： 2014-10-14
上传用户：zuozuo1215
tiny Encryption Algorithm for secure communication.
标签： communication Encryption Algorithm secure
上传时间： 2014-01-03
上传用户：大三三
随着国内交流伺服电机等硬件技术逐步成熟，高运算能力的控制芯片与电机控制技术相结合，具有高效、节能和可移植性好等特点，这样使得交流伺服系统成为现代电机伺服驱动系统的一个发展趋势。 本文主要是基于MCU研究和设计了交流永磁电机位置伺服控制系统。针对三相永磁同步电机的物理方程，通过坐标转换，在d-q旋转坐标系下建立转矩方程，采用Id=0的矢量控制策略，建立一套完整的全数字交流位置伺服控制系统。 硬件方面，采用的是瑞萨公司专用电机控制tiny系列芯片M30262F8作为控制芯片，并由三菱公司的第三代IPM模块PS21564实现功率驱动，简化了系统电路，缩小了系统的体积，提高了系统的可靠性。由交流电流传感器检测三相定子绕组电流；由增量式磁性编码器检测永磁转子位置，并设计一种比较快速的转子初始检测方法。 软件方面，采用结构化语言C和单片机M16C汇编语言混编，实现了单片机初始化、三环控制、电流跟随型PWM控制，提高编写代码的效率，同时保证系统的实时控制性能；由软件方式实现经典PID控制和简单模糊控制相结合构成“串联校正”闭环控制系统，提高了系统的快速性和抗干扰能力。此外，本文对控制策略进行了研究，阐述了模糊PID控制策略；还介绍了SPWM、SVPWM和跟随型PWM调制。 实验结果表明，本文所设计的伺服控制系统能实现电机的启动，调速和定位等，并能达到系统的性能指标。
上传时间： 2013-05-19
上传用户：327000306
Abstract: The MAX3108 is a complete high-performance universal asynchronous receiver-transmitter (UART) in a tiny 2.1mm ×
标签： Programming Rates Baud 3108
上传时间： 2014-12-23
上传用户：清风冷雨
The LM20, LM45, LM50, LM60, LM61, and LM62 are analog output temperature sensors. They have various output voltage slopes (6.25mV/°C to 17mV/°C) and power supply voltage ranges (2.4V to 10V).The LM20 is the smallest, lowest power consumption analog output temperature sensor National Semiconductor has released. The LM70 and LM74 are MICROWIRE/SPI compatible digital temperature sensors. The LM70 has a resolution of 0.125°C while the LM74 has a resolution of 0.625°C. The LM74 is the most accurate of the two with an accuracy better than ±1.25°C. The LM75 is National’s first digital output temperature sensor, released several years ago.
上传时间： 2014-12-23
上传用户：yl8908
The LTC®3414 offers a compact and efficient voltage regulatorsolution for point of load conversion in electronicsystems that require low output voltages (down to 0.8V)from a 2.5V to 5V power bus. Internal power MOSFETswitches, with only 67mW on-resistance, allow theLTC3414 to deliver up to 4A of output current with efficiencyas high as 94%. The LTC3414 saves space by operatingwith switching frequencies as high as 4MHz, enabling theuse of tiny inductors and capacitors.
上传时间： 2014-01-03
上传用户：dongbaobao
Automotive batteries, industrial power supplies, distributedsupplies and wall transformers are all sources ofwide-ranging high voltage inputs. The easiest way to stepdown these sources is with a high voltage monolithicstep-down regulator that can directly accept a wide inputrange and produce a well-regulated output. The LT®3493accepts inputs from 3.6V to 36V and LT3481 acceptsinputs from 3.6V to 34V. Both provide excellent lineand load regulation and dynamic response. The LT3481offers a high effi ciency solution over a wide load range andkeeps the output ripple low during Burst Mode® operationwhile the LT3493 provides a tiny solution with minimalexternal components. The LT3493 operates at 750kHzand the LT3481 has adjustable frequency from 300kHzto 2.8MHz. High frequency operation enables the use ofsmall, low cost inductors and ceramic capacitors.
上传时间： 2014-12-24
上传用户：Pzj
Handheld designers often grapple with ways to de-bounceand control the on/off pushbutton of portable devices.Traditional de-bounce designs use discrete logic, fl ipflops, resistors and capacitors. Other designs includean onboard microprocessor and discrete comparatorswhich continuously consume battery power. For highvoltage multicell battery applications, a high voltageLDO is needed to drive the low voltage devices. All thisextra circuitry not only increases required board spaceand design complexity, but also drains the battery whenthe handheld device is turned off. Linear Technology addressesthis pushbutton interface challenge with a pairof tiny pushbutton controllers.
上传时间： 2013-11-18
上传用户：ZJX5201314
The LTC®3569 is a compact power solution for handhelddevices. Its tiny 3mm × 3mm QFN package includesthree buck regulators with individually programmableoutput voltages. One regulator supports load currentsup to 1200mA, while the other two support currents to600mA. Two regulators can be paralleled for increasedload capability. Each current-mode regulator is internallycompensated with excellent load and line regulation. Acomplete 2- or 3-output solution requires a minimumof external passive components.
上传时间： 2013-10-11
上传用户：yxgi5
An essential component of a noise-free audio device isa clean power supply, but few switching regulators canoperate at high efficiency while keeping the switchingfrequency out of the audio band. The LTC®3620 fills thisvoid. It is a high efficiency 15mA buck regulator with aprogrammable minimum switching frequency, making itpossible to virtually eliminate audible switching noise. Theinternal synchronous switches and low quiescent currentof this buck regulator provide the ability to maintain highefficiency, while its small footprint makes it ideal for tiny,low power audio applications.
上传时间： 2013-10-21
上传用户：非衣2016
