《基于AT89C51单片机的多级通信系统》-毕业论文（设计）.doc

哈尔滨工业大学本科毕业论文 PAGE XVIII - - 多 机 通 信 [摘 要] 由单片机构成的多机通信系统采用总线型主从式结构。所谓主从式结构，即在多个单片机中，一个主机负责通信管理，其他几个个为从机，从机要负责主机的调度与支配。该设计用AT89C51芯片，并用C语言程序来控制AT89C51，使之能实现多个单片机之间的通信。通信方式为单工通信，一个为主单片机，作为发送方，其他几个为从单片机，作为接收方。对于两片8051，发送方的数据由串行口TXD端输出，通过74LS05反向驱动，经光电耦合器至平衡差信号输出，经过传输线（双胶线）将信号传送到接收端。接收方通过平衡差分长线接收芯片75175将差分信号转换成TTL电平信号，通过反向驱动后，经光电耦合器到达接收方串行口的接收端。 [关 键 词] AT89C51；单片机；多机通信 Multicomputer communication Cui Linlin (Grade07,Class4,Major of Communication Engineering，Dept. of E.I.of Shaanxi University of Technology, Hanzhong 723003,China) Tutor:Wang Zhanbei [Abstract] Dual posed by the MCU using bus-based communication system master-slave structure. The so-called master-slave structure, that is, two microcontrollers, a master is responsible for communication management, and the other from the machine, the host from the confidential responsible for scheduling and disposal. AT89C51 chip with the design and use of C language program to control the AT89C51, so that it can achieve communication between two microcontrollers. Communication is simplex, a main microcomputer, as the sender, the other is from the microcontroller, as receiver. For the two 8051, the sender of the data from serial port TXD-ended output, driven by 74LS05 reverse, the optocoupler to balance the difference signal output, through the transmission line (Shuangjiao line) the signal to the receiver. Long-term through a balanced differential receiver chip 75175 to receive the differential signal into a TTL level signal, through the reverse drive, via optocoupler receiver serial port to reach the receiver [Key words] AT89C51; SCM; Multicomputer communication 目 录 TOC \o \h \z HYPERLINK \l _Toc281912261 摘 要 PAGEREF _Toc281912261 \h I HYPERLINK \l _Toc281912262 Abstract PAGEREF _Toc281912262 \h II 1 绪论…………………………………………………………………………2 HYPERLINK \l _Toc281912263 1.1 课题背景 PAGEREF _Toc281912263 \h 2 HYPERLINK \l _Toc281912264 1.1.1 单片机 PAGEREF _Toc281912264 \h 2 HYPERLINK \l _Toc281912265 1.1.2 C语言： P