单片机在条形码扫描仪中的应用

利用MCS-51单片机内的一个逻辑器件和单片机的输出巧妙地得到一个外部中断控制信号，该信号的宽度对应扫描到的脉冲宽度。它处上升沿时，启动单片机内的定时器，下降沿时，停止单片机内的定时器，并请求中断。统计出在该信号为高电平期间的计数脉冲的个数，便可算出该信号高电平的持续时间，即脉冲宽度。在中断服务程序中对定时器采集的数据进行提取，这个数据便是扫描到的脉冲宽度。这一扫描方法的电路结构简单，实用价值高。     

单片机在电话录音中的应用

利用单片机及其接口电路把电话机和收录机结合起来 ,实现自动录音达到智能化的效果 ;利用铃流经整流后得到的直流电压作为中断请求信号 ,单片机响应中断请求 ,通过运行中断服务程序对各接口电路实施控制 ,具有广泛的应用性、科学性     

双向通信控制系统的实验教学设计与实践

以16位低功耗单片机MSP430F5529为控制核心,以智能小车为载体,设计了双向通信控制系统实验。该实验能够帮助学生熟悉单片机控制系统的结构及工作原理。实验涉及中断控制、ADC采样转换、异步串口通信协议、脉冲宽度调制、液晶屏驱动与显示、直流电机的驱动、舵机的驱动等。该实验能够较好地帮助学生理解单片机的系统控制功能,亦可作为大学生电子设计竞赛和大学生创新项目的实训实验。     

微机接口技术练习题

1　选择题(1)CPU执行OUTDX ,AL指令时 ,(　　 )的值输出到地址总线上。　A .AL寄存器　　　　　　B .AX寄存器　C .DL寄存器　　　　　　D .DX寄存器(2 )一个I/O地址称为一个 (　　 )。　A .接口　　　　　　　　　B .端口　C .外设　　　　　　　　　D .芯片(3)地址译码器的输入端应接到 (　　 )上。　A .控制总线　　　　　　　B .数据总线　C .地址总线　　　　　　　D .外部总线(4 )CPU响应可屏蔽中断请求时 ,其中断类型码由 (　　 )提供。　A .CPU内部　　　　　　　B .中断指令　C .类型码固定　　　　D .可屏蔽中断…     

微机接口技术综合练习

1　选择题(1)CPU执行OUTDX ,AL指令时 ,(　　 )的值输出到地址总线上。　A .AL寄存器　　　　　B .AX寄存器　C .DL寄存器　　　　D .DX寄存器(2 )一个I/O地址称为一个 (　　 )。　A .接口　B .端口　C .外设　D .芯片(3 )地址译码器的输入端应接到 (　　 )上。　A .控制总线　B .数据总线　C .地址总线　D .外部总线(4)CPU响应可屏蔽中断请求时 ,其中断类型码由 (　　 )提供。　A .CPU内部　B .中断指令　C .类型码固定　D .可屏蔽中断管理器(5) 82 59工作在完全嵌套方式时 ,(　　 )引脚的中断源优先级最高。　A .IR0　…     

微机接口技术综合练习

1 选择填空 （1）CPU执行OUTDX,AL指令时,_的值输出到地址总线上。 A.AL寄存器 B.AX寄存器 C.DL寄存器 　D.DX寄存器 （2）一个I/O地址称为一个_。 A.接口 B.端口 C.外设 D.芯片 （3）地址译码器的输入端应接到_上。 A.控制总线 B.数据总线 C.地址总线 D.外部总线 （4）CPU响应可屏蔽中断请求时,其中断类型码由_提供。 A.CPU内部 B.中断指令 C.类型码固定 D.可屏蔽中断管理器 （5）8259作在完全嵌套方式时,_引脚的中断源优先级最高。 A.IR0 B.IR1 C.IR7 D.IR8     

微机接口技术综合练习

1　选择题(1)ＣＰＵ执行ＯＵＴＤＸ ,ＡＬ指令时 ,(　　 )的值输出到地址总线上。　Ａ .ＡＬ寄存器　　　　　Ｂ .ＡＸ寄存器　Ｃ .ＤＬ寄存器　　　　　Ｄ .ＤＸ寄存器(2 )一个Ｉ/Ｏ地址称为一个 (　　 )。　Ａ .接口　　　　　　　Ｂ .端口　Ｃ .外设　　　　　　　Ｄ .芯片(3)地址译码器的输入端应接到 (　　 )上。　Ａ .控制总线　　　　　Ｂ .数据总线　Ｃ .地址总线　　　　　Ｄ .外部总线(4)ＣＰＵ响应可屏蔽中断请求时 ,其中断类型码由 (　　 )提供。　Ａ .ＣＰＵ内部　　　　　Ｂ .中断指令　Ｃ .类型码固定Ｄ .可屏蔽中断管理器(5…     

YAG激光输出特性研究

主要研究了JSY-01型脉冲Nd:YAG激光的输出特性。并通过自行设计的实验对YAG激光的偏振特性、光谱特性和脉冲宽度进行了论证和剖析。特别是提出了一种相纸旋转曝光方法,定性地测出了激光的脉冲光强随时间的变化规律。使研究性物理实验在本科实验教学中得到了很好的应用。     

基于晶体电光效应的Nd~(3+)∶YAG激光器调Q实验

为了定量研究由偏振片和KD*P晶体构成的电光Q开关在脉冲Nd3+∶YAG激光器中的应用,在阐述晶体电光效应如何实现激光器调Q基本原理的基础上,从调Q激光器的速率方程出发分析调Q脉冲的形成过程,对调Q脉冲的峰值功率、脉冲宽度特性进行了分析,表明控制反转粒子数密度对提高调Q脉冲质量的重要性。依据所建的激光调Q系统最终实现了KD*P晶体电光调Q、小孔选模、本征级放大、倍频波长532 nm的激光输出,并对调Q前后的激光脉宽、能量进行实验测量与对比分析。实验系统分本征级与放大级两级设计,不仅压缩了激光突发脉冲宽度使其小于20 ns,获得了高的峰值功率,还进一步提高了激光输出能量达到500 mJ。     

高效的串口接收程序

阐述了外部中断在工控机应用中的特殊地位以及WINDOWS与DOS在这方面的不同，通过一个典型的范例说明了DOS在处理中断中所具有的灵活性和高效性。本文对于以串口作为通讯口的应用有很好的参考价值。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.     

团图为数的图中的闭团贯数

Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.