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通用编程器是每个单片机应用开发工作者必不可少的开发工具,其工作原理是先保证目标MCU进入监控状态,然后实现擦除及编程。而在保证目标MCU进入监控状态的硬件条件中,很重要的一项是需要给目标MCU提供一定频率的时钟信号。 相似文献
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基于FPGA的SDRAM的控制器实现与性能分析 总被引:1,自引:0,他引:1
高速数据采集在通信、雷达、引信编程监测和视频图像处理等系统中具有广泛的应用,系统中大量使用SDRAM实现数据缓存。SDRAM以其体积小、容量大、读写速度快、成本低等特点被广泛应用于工业电子设备中。本文在介绍SDRAM工作原理的基础上,提出了一种基于FPGA控制SDRAM控制器的方法,这种控制器以FPGA为基础,将较难控制的SDRAM转化为用硬件描述语言编写其控制器,从而将复杂问题简单化,进而利用Verilog语言在Quartus9.1的开发环境中进行了设计输入与仿真验证,证明系统的正确性并分析SDRAM如何达到最优性能。 相似文献
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提出了一种利用FPGA发出的伪随机序列检测微弱光信号的方法。用伪随机序列调制LED或LD光源,注入测量光纤,输出光信号经过光电转换后与伪随机序列的调制信号做相关检测。由于伪随机序列具有与白噪声相近的相关特性,测量过程中的干扰、噪声对相关峰值影响很小。因此,可以检测到微弱的输出光信号,提高了测量精度。测量系统由LabVIEW虚拟仪器实现。 相似文献
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建立测定速溶咖啡中糠醛和5-羟甲基糠醛的气相色谱–质谱法。样品经乙腈提取,100 mg C18、50 mg强阳离子交换剂(SCX)、150 mg无水MgSO4净化,经HP-INNOWAX毛细管柱分离,选择离子扫描(SIM)模式,同位素内标法定量。糠醛、5-羟甲基糠醛的质量浓度在0.001~8.0μg/mL范围内线性关系良好,相关系数大于0.999,方法检出限为0.080~0.083 mg/kg,平均回收率为91.8%~96.8%,相对标准偏差为2.8%~6.5%(n=5)。该方法简单快速、灵敏可靠,为速溶咖啡中糠醛、5-羟甲基糠醛的提取和检测提供了可靠的技术支撑。 相似文献
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Highly conductive and transparent carbon nanotube-based electrodes for ultrathin and stretchable organic solar cells 下载免费PDF全文
In this work, we have presented a freestanding and flexible CNT-based film with sheet resistance of 60 ?/ and transmittance of 82% treated by nitric acid and chloroauric acid in sequence. Based on modified CNT film as a transparent electrode, we have demonstrated an ultrathin, flexible organic solar cell(OSC) fabricated on 2.5-μm PET substrate. The efficiency of OSC, combined with a composite film of poly(3-hexylthiophene)(P3HT) and phenyl-C61 butyric acid methyl ester(PCBM) as an active layer and with a thin layer of methanol soluble biuret inserted between the photoactive layer and the cathode, can be up to 2.74% which is approximate to that of the reference solar cell fabricated with ITO-coated glass(2.93%). Incorporating the as-fabricated ITO-free OSC with pre-stretched elastomer, 50% compressive deformation can apply to the solar cells. The results show that the as-prepared CNT-based hybrid film with outstanding electrical and optical properties could serve as a promising transparent electrode for low cost, flexible and stretchable OSCs, which will broaden the applications of OSC and generate more solar power than it now does. 相似文献
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分析了嵌入式开发中不同MCU串行通信编程的共性,根据软件工程的基本原理提取了MCU串行通信编程的基本要素,把编程要素分为通用部分和个性部分。对于通用部分,给出了能够适用于各种MCU的串行通信程序,对于个性部分,给出了基本编程原理与移植要点。给出的设计方法和程序,分别在8位、16位、32位MCU上进行了测试,可以成为嵌入式开发中的一个通用部件。 相似文献
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Highly flexible and excellent performance continuous carbon nanotube fibrous thermoelectric modules for diversified applications 下载免费PDF全文
Xiao-Gang Xia 《中国物理 B》2021,30(7):78801-078801
A highly flexible and continuous fibrous thermoelectric (TE) module with high-performance has been fabricated based on an ultra-long single-walled carbon nanotube fiber, which effectively avoids the drawbacks of traditional inorganic TE based modules. The maximum output power density of a 1-cm long fibrous TE module with 8 p-n pairs can reach to 3436 μW·cm-2, the power per unit weight to 2034 μW·g-1, at a steady-state temperature difference of 50 K. The continuous fibrous TE module is used to detect temperature change of a single point, which exhibits a good responsiveness and excellent stability. Because of its adjustability in length, the flexible fibrous TE module can satisfy the transformation of the temperature difference between two distant heat sources into electrical energy. Based on the signal of the as-fabricated TE module, a multi-region recognizer has been designed and demonstrated. The highly flexible and continuous fibrous TE module with excellent performance shows a great potential in diversified applications of TE generation, temperature detection, and position identification. 相似文献