MMC/SD卡以其優越的性能，在單片機嵌入式設備中得到廣泛應用。將MMC/SD卡作為外部掉電存儲介質應用于音頻信號發生器中，通過8051F330單片機上的SPI接口，實現單片機—MMC/SD卡的存儲擴展，設計了此硬件平臺上的MMC/SD卡的單片機驅動程序，并給出了相應的程序代碼，滿足音頻信號發生器的大容量存儲要求。 Abstract: MMC/SD card is more and more widely used in the single chip embedded devices for their excellent performances.This article introduces the application of MMC/SD card as the external power down storage medium in audio signal generator. The extension technology especially for storage of single chip-MMC/SD card via SPI interfaces in 8051F330 single chip, including designs single chip drive program of MMC/SD card based on hardware platform,and also gives the key coding of the program. The implementation of big capacity storage is meaningful in audio signal generator.
上傳時間： 2014-12-27
上傳用戶：黃華強
采用單片機AT89C2051實現溫度測量與控制,鍵盤和顯示電路實現溫度的設定、修改、清零以及當前溫度值的顯示,并對溫度超過上下限進行報警。闡述了該系統設計的硬件和軟件設計。 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．
上傳時間： 2013-11-18
上傳用戶：leehom61
針對眾多低成本數據采集需求，采用帶有片上USB控制器和D/A轉換器的混合信號微處理器C8051F340，設計了一款可通過USB接口和LabVIEW圖形用戶界面實現與PC機聯機的數據采集器，同時借助系統的SD卡存儲獨立實現現場長時間采集數據。該數據采集器成本低，結構簡單，體積小，已成功用于工業現場。 Abstract: Aiming at the need of low cost data acquisition, a data acquisition device is designed based on C8051F340 which is a mixed-signal microcontroller and integrates USB controller and A/D controller on a chip.The data acquisition device which can combine with PC by USB interface and LabVIEW graphical user interface,can realize data acquisition. At the same time,it can be solely run a long time in virtue of SD card in field.The date aequisition device features low cost,simple structure and little sharp, and it has been used in industry field.
上傳時間： 2014-05-31
上傳用戶：1109003457
介紹一種無極可調交流電子負載設計的新方法，由ATmega48單片機輸出PWM波，通過上位機設定不同的占空比控制場效應管的通斷時間，即改變流過場效應管的平均電流。根據電流的大小，可以等效為相應的負載，并將采集的電流值顯示在上位機上。文中對該系統的軟﹑硬件設計思路作了詳細的分析，闡述了其設計原理。 Abstract: A new type electronic load is introduced.Due to ATmega48 microcomputer output PWM wave.The different duty is set ratio through PC to control FET turn-on time.We can equivalent homologous load according the current and display the current at PC.The hardware and software designing are analysed in detail. The principle is explained and the output is also given.
上傳時間： 2013-11-23
上傳用戶：蟲蟲蟲蟲蟲蟲
對于傳統的跑步機無法聯機組網，保存歷史數據，實時調試等問題，介紹了一個由多臺跑步機通過RS-232串行總線與上位機相連組成的跑步機聯網系統。系統采用W77E58作為下位機核心控制器件，它具有雙串行通訊端口，其中一個串口用于與變頻器通訊，另一個串口則與上位機相連，構成跑步機網絡。 Abstract: The traditional running machine can not be connected to a network, saving historical data, real time debug etc.In this paper,a new network system which is composed of running machines connected by a RS-232 communication bus is introduced.In the system,W77E58 is used as a core control unit.W77E58 has two serial ports,one is connected to the inverter and the other is connected to the PC. Thus a network appears.
上傳時間： 2014-12-27
上傳用戶：哇哇哇哇哇
為了解決磁放大器性能測試過程中，需要對其供給不同數值恒定電流的問題，設計了一種基于DAC7512和單片機的數控恒流源系統。該系統采用AT89C51作為主控器件，將計算機發送的電流控制字命令轉換為D/A轉換器控制字，通過模擬SPI通信接口，寫D/A控制字到DAC7512，從而控制其輸出相應數字電壓值，經差動縮放電路、電壓/電路變換電路和功率驅動電路，最后輸出恒定電流。實驗結果表明，恒流源輸出電流調節范圍為-45~+45 mA、精度為±0.1 mA，分辨率達0.024 4 mA，具有應用靈活，外圍電路簡單，可靠性高的特點。該數控直流恒流源也可為相關產品的測試系統研發提供參考。 Abstract: In order to solve the need to supply different values constant current for the magnetic amplifier in testing process， numerical control constant current source system was designed based on DAC7512 chip and microcontroller technology. The system used the AT89C51 as the main chip， which can convert the current control word from computer into to D/A control words. And the system wrote D/A control word into the DAC7512 chip to control the output voltage value by the SPI communication interface， which can output corresponding constant current figures by scaling circuit， the V/I converter and power drive circuit. Experimental results show that the current source output current adjustment range is -45~+45mA， accuracy is ± 0.1mA， and resolution ratio is 0.024 4mA
上傳時間： 2014-12-27
上傳用戶：invtnewer
針對51單片機系統中常用的A/D轉換器價格高、精度低的缺點，介紹TI公司的16 位的帶有I2C串行接口的A/D轉換器ADS1110的工作原理，給出ADS1110與AT89C51單片機系統的接口電路和軟件設計。實踐證明，ADS1110具有高性價比和實用性。 Abstract: According to the disadvantages of high expense and low accuracy of the general A/D converter used in MCS51 microchip system,the principle and working process of a high accuracy 16-bit A/D conversion ADS1110 which has I2C bus and belongs to TI Company are proposed here as well as the interface of ADS1110 to AT89C51 and software list.It is proved to be high performance index and practicability.
上傳時間： 2013-11-21
上傳用戶：gyq
針對目前采用的熱敏電阻測量方法，提出了采用單總線數字式溫度傳感器DS18B20和單片機組成的新型溫度測量儀。介紹DS18B20的結構和工作原理，以及單總線工作原理，給出了由Mega8單片機和DS18B20構成的單總線溫度測量儀的硬件電路及軟件流程圖。經試驗基于單總線器件DS18B20的溫度測量儀，具有測量準確、測溫范圍寬、體積小、控制方便等優點。 Abstract: This paper brings forward a new temperature meter composed of 1-Wire temperature sensor DS18B20 and MCU which has advantage of the thermistor. In the article, the DS18B20＇s structure and controlling principles are introduced and hardware circuit and software diagram of the temperature meter are given.After been tested,the temperature meter has the advantages of accurate measurement, wide temperature range, small volume and convenient controlling.
上傳時間： 2013-10-31
上傳用戶：hzy5825468
為深入了解基于UC3854A控制的PFC變換器中的動力學特性，研究系統參數變化對變換器中分岔現象的影響，在建立Boost PFC變換器雙閉環數學模型的基礎上，用Matlab軟件對變換器中慢時標分岔及混沌等不穩定現象進行了仿真。在對PFC變換器中慢時標分岔現象仿真的基礎上，分析了系統參數變化對分岔點的影響，并進行了仿真驗證。仿真結果清晰地顯示了輸入整流電壓的幅值變化對系統分岔點的影響。 Abstract: In order to better understand the dynamics characteristic of power factor correction converter based on UC3854A， and make the way that parameters change influences the bifurcation phenomena of the system clearly. The math model of the two closed loop circuits to the Boost PFC （Power Factor Correction） converter controller was built. Then， with the help of Matlab， the simulation for nonlinear phenomena such as chaos and slow-scale bifurcation in the PFC converter was made. Finally the factors that have influence to the phenomenon of bifurcation under slow-scale in PFC converter were analyzed. The simulation results clearly show the parameters change influences the bifurcation point of the system.
上傳時間： 2013-10-17
上傳用戶：杜瑩12345
以AVR單片機ATmega8和USB接口器件PDIUSBD12為核心，基于標準的USB1.1協議，設計一種通用USB接口模塊，以滿足嵌入式系統中對USB接口的需求。對模塊的硬件電路或單片機固件程序的硬件接口層稍加修改即可用于其他各種微處理器。該模塊可為各種嵌入式系統增加USB接口,實現與USB主機系統通信。 Abstract: Based on AVR microcontroller ATmega8 and USB interface chip PDIUSBD12, a general USB interface module is designed according to USB1.1 protocol for various requirements of embedded systems. Only with few modifications in circuit or hardware abstract layer of firmware, the module can be used on many types of microprocessors. All kinds of embedded systems can realize high speed and stable communication with USB host systems, owing to the facility of this module.
上傳時間： 2014-01-08
上傳用戶：趙云興
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