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lower

数据库函数,用于将字符串类型值的大写字母全部转换成小写字母。
  • 基于AT89C2051的温度监控系统的设计

    采用单片机AT89C2051实现温度测量与控制,键盘和显示电路实现温度的设定、修改、清零以及当前温度值的显示,并对温度超过上下限进行报警。阐述了该系统设计的硬件和软件设计。 Abstract:  The system of temperature measuring and controling is realized based on AT89C2051.The keyboard and display circuit is designed,which can be used for setting and modifying temperature value,resetting and displaying the present temperature value.At the same time the warning circuit is also designed in the system,which can deal with the alarm when temperature exceeds the upper limit and the lower limit.The hardware and software design of the system are explained.

    标签: C2051 2051 89C AT

    上传时间: 2013-11-18

    上传用户:leehom61

  • MAX7456在可视倒车雷达中的应用

    为解决传统可视倒车雷达视频字符叠加器结构复杂,可靠性差,成本高昂等问题,在可视倒车雷达设计中采用视频字符发生器芯片MAX7456。该芯片集成了所有用于产生用户定义OSD,并将其插入视频信号中所需的全部功能,仅需少量的外围阻容元件即可正常工作。给出了以MAX7456为核心的可视倒车雷达的软、硬件实现方案及设计实例。该方案具有电路结构简单、价格低廉、符合人体视觉习惯的特点。经实际装车测试,按该方案设计的可视倒车雷达视场清晰、提示字符醒目、工作可靠,可有效降低驾驶员倒车时的工作强度、减少倒车事故的发生。 Abstract:  A new video and text generation chip,MAX7456,was used in the design of video parking sensor in order to simplify system structure,improve reliability and reduce cost. This chip included all the necessary functions to generate user-defined OSDs and to add them into the video signals. It could be put into work with addition of just a small number of resistances and capacitors. This paper provided software and hardware implementation solutions and design example based on the chip. The system had the characteristics of simplicity in circuit structure,lower cost,and comfort for the nature of human vision. Loading road test demonstrates high video and text display quality and reliable performance,which makes the driver easy to see backward and reduces chance of accidents.

    标签: 7456 MAX 可视倒车 中的应用

    上传时间: 2013-12-10

    上传用户:qiaoyue

  • 基于AT89S52 的水温控制系统的设计

    本文介绍了基于AT89C52 单片机的自动水温控制系统的设计及实现过程。该系统具有实时显示、温度测量、温度设定并能根据设定值对环境温度进行调节实现控温的目的以及达到上下限温度报警功能,控制算法是基于数字PID 算法。关键词 :PID AT89C52 脉宽调制 实时 Abstract : This article describes AT89C52 single-chip microcomputer-basedautomatic water temperature control system design and implementation process. Thesystem has real-time display, temperature measurement, temperature settings and theenvironment in accordance with the temperature settings adjusted to achieve thepurpose of temperature control and reach the upper and lower limits of temperaturealarm function, the control algorithm is based on the digital PID algorithm.Keyword: PID AT89C52 PWM real time

    标签: 89S S52 AT 89

    上传时间: 2013-10-10

    上传用户:归海惜雪

  • LLCR Pin Socket Testing with t

    LLCR Pin Socket Testing with the Model 3732 High Density Matrix Card Computer processors (CPUs) today have come a long way from the computer processors of the past. They draw more power, run at lower voltages, and have more pins than ever before.

    标签: Testing Socket LLCR with

    上传时间: 2013-10-24

    上传用户:whenfly

  • PCA9534—带中断的低功耗8位I2C和SMBus IO口

    The PCA9534 is a 16-pin CMOS device that provide 8 bits of General Purpose parallel Input/Output (GPIO) expansion for I2C-bus/SMBus applications and was developed to enhance the NXP Semiconductors family of I2C-bus I/O expanders. The improvements include higher drive capability, 5 V I/O tolerance, lower supply current, individual I/O configuration, 400 kHz clock frequency, and smaller packaging. I/O expanders provide a simple solution when additional I/O is needed for ACPI power switches, sensors, push buttons, LEDs, fans, etc.

    标签: SMBus 9534 PCA I2C

    上传时间: 2013-11-17

    上传用户:vodssv

  • PCA9534 8bit I2C bus and SMBus low power IO port with interru

    The PCA9534 is a 16-pin CMOS device that provide 8 bits of General Purpose parallel Input/Output (GPIO) expansion for I2C-bus/SMBus applications and was developed to enhance the NXP Semiconductors family of I2C-bus I/O expanders. The improvements include higher drive capability, 5 V I/O tolerance, lower supply current, individual I/O configuration, 400 kHz clock frequency, and smaller packaging. I/O expanders provide a simple solution when additional I/O is needed for ACPI power switches, sensors, push buttons, LEDs, fans, etc.

    标签: interru SMBus power 9534

    上传时间: 2013-10-10

    上传用户:inwins

  • PCA9535 PCA9535C 16bit I2C bus

    The PCA9535 and PCA9535C are 24-pin CMOS devices that provide 16 bits of GeneralPurpose parallel Input/Output (GPIO) expansion for I2C-bus/SMBus applications and wasdeveloped to enhance the NXP Semiconductors family of I2C-bus I/O expanders. Theimprovements include higher drive capability, 5 V I/O tolerance, lower supply current,individual I/O configuration, and smaller packaging. I/O expanders provide a simplesolution when additional I/O is needed for ACPI power switches, sensors, push buttons,LEDs, fans, etc.

    标签: 9535 PCA 9535C I2C

    上传时间: 2013-10-21

    上传用户:爱死爱死

  • PCA9555 16bit I2C-bus and SMBu

    The PCA9555 is a 24-pin CMOS device that provides 16 bits of General Purpose parallelInput/Output (GPIO) expansion for I2C-bus/SMBus applications and was developed toenhance the NXP Semiconductors family of I2C-bus I/O expanders. The improvementsinclude higher drive capability, 5 V I/O tolerance, lower supply current, individual I/Oconfiguration, and smaller packaging. I/O expanders provide a simple solution whenadditional I/O is needed for ACPI power switches, sensors, push buttons, LEDs, fans, etc.The PCA9555 consists of two 8-bit Configuration (Input or Output selection); Input, Outputand Polarity Inversion (active HIGH or active LOW operation) registers. The systemmaster can enable the I/Os as either inputs or outputs by writing to the I/O configurationbits. The data for each Input or Output is kept in the corresponding Input or Outputregister. The polarity of the read register can be inverted with the Polarity Inversionregister. All registers can be read by the system master. Although pin-to-pin and I2C-busaddress compatible with the PCF8575, software changes are required due to theenhancements, and are discussed in Application Note AN469.

    标签: C-bus 9555 SMBu PCA

    上传时间: 2013-11-13

    上传用户:fredguo

  • 基于单片机的步进电机开环控制系统

    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

    标签: 单片机 步进电机 开环 控制系统

    上传时间: 2013-10-13

    上传用户:cicizoe

  • WP312-Xilinx新一代28nm FPGA技术简介

    Xilinx Next Generation 28 nm FPGA Technology Overview Xilinx has chosen 28 nm high-κ metal gate (HKMG) highperformance,low-power process technology and combined it with a new unified ASMBL™ architecture to create a new generation of FPGAs that offer lower power and higher performance. These devices enable unprecedented levels of integration and bandwidth and provide system architects and designers a fully programmable alternative to ASSPs and ASICs.

    标签: Xilinx FPGA 312 WP

    上传时间: 2014-12-28

    上传用户:zhang97080564