基于单片机的多路模拟输及通信设计论文.doc

摘 要 模拟信号的输出是生产过程中非常重要的一个环节，直接影响到。本设计是设计一个8路的模拟量输出系统，外部信号由RS-485通信传送给控制器作为控制的依据，决定每路模拟量输出通道输出的大小。本设计要求输出4-20mA电流。精度要求做到1%。因此本设计采用的单片机是AT80C51，只所以采用51单片机是因为该单片机在软件编写时，用C语言编写比较的灵活，价格便宜。采用的DA芯片是DAC0832，DAC0832的转换精度可以做到1%：D/A，单片机，异步串行通信ABSTRACT The output of the analog signal is very important for the production process, which directly affects the control system performance. The use of PC control system is often encountered in an industrial production problems, the use of PC control via RS-485 chip is not only easy to control, but also can save substantial operating costs while improving control security. The structure of the whole system is simple, it has high reliability. This article highlights the systems hardware design. This paper is to design an 8-way analog output system, receiving an external signal, is the external signal the decision of each analog output channel. The external signal transmitted by the RS-485 communications to the controller as the control basis. The design which output is 4-20mA current is to achieve 1% accuracy. Therefore, a microcontroller which is used by this design is the AT80C51, because the use of 51 single-chip microcontroller in software development when compared with the C language flexible and cheaper prices is very good. DA chip which we use is DAC0832, DAC0832 can do the conversion accuracy of 1%. KEY WORDS: D/A, microcomputer, asynchronous serial communication目 录 摘 要 I ABSTRACT I 第1章 绪 论 1 1.1 课题背景 1 1.2 研究的意义 1 1.3 研究的对象 1 第2章 总体方案设计 2 2.1系统总体设计 2 2.2本系统工作流程 2 第3章 硬件设计 4 3.1 AT80C51功能简介 4 3.2 CPU最小系统设计 4 3.2.1晶振原理设计 5 3.2.2复位电路设计： 6 3.3 单片机与DAC0832接口的设计 8 3.3.1 DAC0832的功能简介 8 3.3.2 DAC0832的工作原理 8 3.3.3 具体接口设计 10 3.3.4 输出电路设计 11 3.4 单片机串口通信设计 12 3.4.1 RS-485收发器介绍 13 3.4.2 RS-485通信模块设计 14 3.5 电源模块 16 第4章 软件部分 19 4.1 主程序设计 19 4.2 DA转换程序设计 20 4.3 通信设置 20 4.3.1 串口控制寄存器SCON的设置 20 4.3.2 定时器内部主要寄存器 21 4.3.3波特率计算 22 4.4通信程序流程图 22 第5章 总结与展望 26 5.1总结 26 5.2展望 26 致 谢 27 参考文献 28 第1章 绪 论 1.1 课题背景 随着单片机技术的迅速兴起发展，其稳定、安全、高效、经济等优点突出，其应用也。单