The main oscillator allows either a crystal or single-ended input clock signal. Cost-sensitiveapplications typically use an external crystal with the on-chip oscillator circuit since it is the mostcost-effective solution. It is also possible to use the internal oscillator to clock the device after theboot process has completed.
标签： Stellaris Clocking Options for
上传时间： 2013-10-14
上传用户：pol123
基于单DSP的VoIP模拟电话适配器研究与实现:提出和实现了一种新颖的基于单个通用数字信号处理器(DSP)的VoIP模拟电话适配器方案。DSP的I/O和存储资源非常有限，通常适于运算密集型应用，不适宜控制密集型应用[5]。该系统高效利用单DSP的I/O和片内外存储器资源，采用μC/OS-II嵌入式实时操作系统，支持SIP和TCP-UDP/IP协议，通过LAN或者宽带接入，使普通电话机成为Internet终端，实现IP电话。该系统软硬件结构紧凑高效，运行稳定，成本低，具有广阔的应用前景。关键词：模拟电话适配器；IP电话；数字信号处理器；μC/OS-II 【Abstract】This paper presents a VoIP ATA solution based on a single digital signal processor (DSP). DSPs are suitable for arithmetic-intensiveapplication and unsuitable for control-intensive application because of the limitation of I/O and memory resources. This solution is based on a 16-bitfixed-point DSP and μC/OS-II embedded real-time operating system. It makes good use of the limited resources, supports SIP and TCP-UDP/IPprotocol. It can connect the analog telephone to Internet and realize the VoIP application. This system has a great future for its high efficiency andlow cost.【Key words】Analog telephone adapter (ATA); Voice over Internet protocol (VoIP); Digital signal processor (DSP); μC/OS-II Research and Implementation of VoIPATA Based on Single DSP
上传时间： 2013-11-20
上传用户：Wwill
基于单片机的步进电机开环控制系统:通过ATMEL89C51单片机对步进电机进行控制,主要介绍了步进电机控制器、驱动电路和LED显示电路的设计,实现了步进电机的开环控制。在步进电机控制器的设计中,重点阐述了脉冲产生电路以及对速度的控制。该系统具有成本低、控制方便的特点。关键词: 单片机; 步进电机; 开环控制 Abstract: The design using ATMEL89C51 single chip to control the step2motor with its controller, driving circuit and LED disp lay circuit to realize step motor open2loop controlwere introduced. For the controller in this design,the circuit to p roduce pulse and the speed controlwere expatiated emphatically. This system possesses features of lower cost, easier control.Key words: single ch ip; step2motor; open2loop con trol
上传时间： 2013-10-13
上传用户：cicizoe
摘要：本水位监测报警器使用5V低压直流电源（也可以用3节5号电池代替）就可以对5~15厘米的水位进行监测，用LED显示和数码管显示水位，并可以对不再此范围内的水位发出报警。主要采用CD4066、74LS86、74LS32、CD4511芯片，再加上数码管、蜂鸣器、发光二极管、电阻这些器件组成一个简单而灵敏的监测报警电路，操作简单，接通电源即可工作。因为大部分电路采用数字电路，所以本水位监测报警器还具有耗能低、准确性高的特点。关键字：译码电路 报警电路 监测电路 Abstract: The water level alarm monitoring the use of 5 V low-voltage DC power (can also use three batteries replaced on the 5th) will be able to 5 to 15 centimeters of water level monitoring, with LED display and digital display of water level, and this can no longer Within the scope of a water level alarm. Mainly CD4066, 74LS86, 74LS32, CD4511 chips, coupled with digital control, buzzer, light-emitting diode, the resistance of these devices composed of a simple and sensitive monitoring alarm circuits. Because the majority of circuits using digital circuitry, so the water level monitored alarm system also has low energy consumption, high accuracy of the characteristics. Keyword: Decoding circuit alarm circuit monitoring circuit
上传时间： 2013-11-05
上传用户：王庆才
基于PIC单片机的低功耗读卡器硬件设计:本文提出了一个完整的基于串口的智能读卡器子系统设计方案并将其实现。读卡器的设计突出了小型化的要求，全部器件使用贴片封装。为了减小读卡器的体积，设计中还使用了串口窃电的技术，使用串口信号线直接给读卡器供电。为此，读卡器使用了省电的设计，采用了省电的集成电路，并大胆简化了许多传统的设计电路。关键字： 读卡器， 单片机， 串口窃电 Abstract： This paper aims to put forward a complete design of Smart IC card reader based onSerial Port and propose the way of realizing it for the purpose of Network Security. SMD isadopted to make Smart IC reader smaller in this design. To reduce the volume of Smart ICreader， Serial Port powered technology is employed to get power from the signal line of Serial Port. For this reason， low-power consumption components are adopted in the design and some traditional designs are simplified to reduce the power consumption.Keywords： Card Reader； Single-chip Computer； Serial Port Powered IC 卡系统保存了加密算法所需要的工作密钥，供加密算法对网络上传输的数据加密使用，是整个系统网络安全的核心。在IC 卡子系统中，读卡器是一个重要的部分。它起着管理IC卡、在IC 卡和PC或网络计算机间传递数据的重要作用。本文以一片PIC单片机为核心完成了基于RS232 串口的读卡器的硬件设计。
上传时间： 2014-04-14
上传用户：wanghui2438
The solution presented in this paper and in the attached source files emulates the mostimportant SSC functions by using SW routines implemented in C. The code is focused onthe SAB C513, but will fit to all C500 derivatives.Beyond the low level software drivers a test shell is delivered. This shell allows a quicktest of the software drivers by an emulator or a starter kit demo board.
上传时间： 2013-11-24
上传用户：363186
All inputs of the C16x family have Schmitt-Trigger input characteristics. These Schmitt-Triggers are intended to always provide proper internal low and high levels, even if anundefined voltage level (between TTL-VIL and TTL-VIH) is externally applied to the pin.The hysteresis of these inputs, however, is very small, and can not be properly used in anapplication to suppress signal noise, and to shape slow rising/falling input transitions.Thus, it must be taken care that rising/falling input signals pass the undefined area of theTTL-specification between VIL and VIH with a sufficient rise/fall time, as generally usualand specified for TTL components (e.g. 74LS series: gates 1V/us, clock inputs 20V/us).The effect of the implemented Schmitt-Trigger is that even if the input signal remains inthe undefined area, well defined low/high levels are generated internally. Note that allinput signals are evaluated at specific sample points (depending on the input and theperipheral function connected to it), at that signal transitions are detected if twoconsecutive samples show different levels. Thus, only the current level of an input signalat these sample points is relevant, that means, the necessary rise/fall times of the inputsignal is only dependant on the sample rate, that is the distance in time between twoconsecutive evaluation time points. If an input signal, for instance, is sampled throughsoftware every 10us, it is irrelevant, which input level would be seen between thesamples. Thus, it would be allowable for the signal to take 10us to pass through theundefined area. Due to the sample rate of 10us, it is assured that only one sample canoccur while the signal is within the undefined area, and no incorrect transition will bedetected. For inputs which are connected to a peripheral function, e.g. capture inputs, thesample rate is determined by the clock cycle of the peripheral unit. In the case of theCAPCOM unit this means a sample rate of 400ns @ 20MHz CPU clock. This requiresinput signals to pass through the undefined area within these 400ns in order to avoidmultiple capture events.For input signals, which do not provide the required rise/fall times, external circuitry mustbe used to shape the signal transitions.In the attached diagram, the effect of the sample rate is shown. The numbers 1 to 5 in thediagram represent possible sample points. Waveform a) shows the result if the inputsignal transition time through the undefined TTL-level area is less than the time distancebetween the sample points (sampling at 1, 2, 3, and 4). Waveform b) can be the result ifthe sampling is performed more than once within the undefined area (sampling at 1, 2, 5,3, and 4).Sample points:1. Evaluation of the signal clearly results in a low level2. Either a low or a high level can be sampled here. If low is sampled, no transition willbe detected. If the sample results in a high level, a transition is detected, and anappropriate action (e.g. capture) might take place.3. Evaluation here clearly results in a high level. If the previous sample 2) had alreadydetected a high, there is no change. If the previous sample 2) showed a low, atransition from low to high is detected now.
上传时间： 2013-10-23
上传用户：copu
The P90CL301 is a highly integrated 16/32 bit micro-controller especially suitable for applications requiring lowvoltage and low power consumption. It is fully software compatible with the 68000. Furthermore, it provides bothstandard as well as advanced peripheral functions on-chip.One of these peripheral functions is the I2C bus. This report describes worked-out driver software (written in C) toprogram the P90CL301 I2C interface. It also contains interface software routines offering the user a quick start inwriting a complete I2C system application.
上传时间： 2014-01-06
上传用户：气温达上千万的
All inputs of the C16x family have Schmitt-Trigger input characteristics. These Schmitt-Triggers are intended to always provide proper internal low and high levels, even if anundefined voltage level (between TTL-VIL and TTL-VIH) is externally applied to the pin.The hysteresis of these inputs, however, is very small, and can not be properly used in anapplication to suppress signal noise, and to shape slow rising/falling input transitions.Thus, it must be taken care that rising/falling input signals pass the undefined area of theTTL-specification between VIL and VIH with a sufficient rise/fall time, as generally usualand specified for TTL components (e.g. 74LS series: gates 1V/us, clock inputs 20V/us).The effect of the implemented Schmitt-Trigger is that even if the input signal remains inthe undefined area, well defined low/high levels are generated internally. Note that allinput signals are evaluated at specific sample points (depending on the input and theperipheral function connected to it), at that signal transitions are detected if twoconsecutive samples show different levels. Thus, only the current level of an input signalat these sample points is relevant, that means, the necessary rise/fall times of the inputsignal is only dependant on the sample rate, that is the distance in time between twoconsecutive evaluation time points. If an input signal, for instance, is sampled throughsoftware every 10us, it is irrelevant, which input level would be seen between thesamples. Thus, it would be allowable for the signal to take 10us to pass through theundefined area. Due to the sample rate of 10us, it is assured that only one sample canoccur while the signal is within the undefined area, and no incorrect transition will bedetected. For inputs which are connected to a peripheral function, e.g. capture inputs, thesample rate is determined by the clock cycle of the peripheral unit. In the case of theCAPCOM unit this means a sample rate of 400ns @ 20MHz CPU clock. This requiresinput signals to pass through the undefined area within these 400ns in order to avoidmultiple capture events.
上传时间： 2014-04-02
上传用户：han_zh
当拿到一张CASE单时，首先得确定的是能用什么母体才能实现此功能，然后才能展开对外围硬件电路的设计，因此首先得了解每个母体的基本功能及特点，下面大至的介绍一下本公司常用的IC：单芯片解决方案• SN8P1900 系列– 高精度 16-Bit 模数转换器– 可编程运算放大器 (PGIA)• 信号放大低漂移: 2V• 放大倍数可编程: 1/16/64/128 倍– 升压- 稳压调节器 (Charge-Pump Regulator)• 电源输入: 2.4V ~ 5V• 稳压输出: e.g. 3.8V at SN8P1909– 内置液晶驱动电路 (LCD Driver)– 单芯片解决方案 • 耳温枪 SN8P1909 LQFP 80 Pins• 5000 解析度量测器 SN8P1908 LQFP 64 Pins• 体重计 SN8P1907 SSOP 48 Pins单芯片解决方案• SN8P1820 系列– 精确的12-Bit 模数转换器– 可编程运算放大器 (PGIA)• Gain Stage One: Low Offset 5V, Gain: 16/32/64/128• Gain Stage One: Low Offset 2mV, Gain: 1.3 ~ 2.5– 升压- 稳压调节器• 电源输入: 2.4V ~ 5V• 稳压输出: e.g. 3.8V at SN8P1829– 内置可编程运算放大电路– 内置液晶驱动电路 – 单芯片解决方案 • 电子医疗器 SN8P1829 LQFP 80 Pins 高速/低功耗/高可靠性微控制器• 最新SN8P2000 系列– SN8P2500/2600/2700 系列– 高度抗交流杂讯能力• 标准瞬间电压脉冲群测试 (EFT): IEC 1000-4-4• 杂讯直接灌入芯片电源输入端• 只需添加1颗 2.2F/50V 旁路电容• 测试指标稳超 4000V (欧规)– 高可靠性复位电路保证系统正常运行• 支持外部复位和内部上电复位• 内置1.8V 低电压侦测可靠复位电路• 内置看门狗计时器保证程序跳飞可靠复位– 高抗静电/栓锁效应能力– 芯片工作温度有所提高: -200C ~ 700C 工规芯片温度： -400C ~ 850C 高速/低功耗/高可靠性微控制器• 最新 SN8P2000 系列– SN8P2500/2600/2700 系列– 1T 精简指令级结构• 1T: 一个外部振荡周期执行一条指令• 工作速度可达16 MIPS / 16 MHz Crystal– 工作消耗电流 < 2mA at 1-MIPS/5V– 睡眠模式下消耗电流 < 1A / 5V额外功能• 高速脉宽调制输出 (PWM)– 8-Bit PWM up to 23 KHz at 12 MHz System Clock– 6-Bit PWM up to 93 KHz at 12 MHz System Clock– 4-Bit PWM up to 375 KHz at 12 MHz System Clock• 内置高速16 MHz RC振荡器 (SN8P2501A)• 电压变化唤醒功能• 可编程控制沿触发/中断功能– 上升沿 / 下降沿 / 双沿触发• 串行编程接口
上传时间： 2013-10-21
上传用户：jiahao131
