基于CPLD的电话计时计费系统

I 基于CPLD的电话计时计费系统 摘要：伴随互联网通信技术的飞速发展以及人们生活水平的提高，通讯设备趋向于高端化和智能化。但固定电话面对如此冲击并未功成身退，反而在面对诸多不可抗力因素中，体现出了其重要的实用价值。 本系统采用EDA技术作为开发方式，以VHDL作为编程语言，以复杂可编程逻辑器件CPLD的为核心，采用自顶向下的模块化设计电话计时计费系统的。 本系统基本实现国际长途电话(IDD)、国内长途电话(DDD)、市内电话及特殊服务电话等的自动计时、计费。具有停电能继续工作8小时以上的功能(利用计费器内的充电干电池)同时具有超限额报警的功能。 本系统核心控制部分主要分为六个大的功能模块，键盘输入、启动控制、分频、计时、计费提示及显示驱动。

关键词 EDA；CPLD；VHDL；电话计时计费 Ⅱ

Telephone time billing system based on CPLD

Abstract :Along with the rapid development of Internet communication technology and the increase of people's living standard, the mobile phone, communications equipment tend to high-end and intelligent. But fixed telephone with such impact did not retire, but in the face of many factors of force majeure, reflects the important practical value. The system uses the EDA technology as development way to VHDL as programming language, to complex programmable logic device of CPLD as the core, and adopting the top-down the modular design of the timing of the telephone billing system. The basic system to realize international long distance telephone (IDD), domestic long distance telephone (DDD), local call and special service phone etc automatic timer, billing. Has the power blackouts, continue to work eight hours above functions (using the message accounting device inside the dry batteries charge) and has ChaoXianE alarm function. This system mainly divided into six big function module, the keyboard input, start frequency and time control, points, billing tip and display drivers.

Key words: EDA; CPLD; VHDL; Telephone timing and billing I

目 录 基于CPLD的电话计时计费系统 ..................................................................................................... I Telephone time billing system based on CPLD ..................................................................... 2 第1章 绪论 ................................................................................................................................... 1 1.1 课题背景 ......................................................................................................................... 1 1.2 目的和意义 ....................................................................................................................... 2 1.3 研究现状 ......................................................................................................................... 2 1.4 可行性分析 ..................................................................................................................... 2 第2章 系统开发工具简介 ........................................................................................................... 3 2.1 Quartus II 简介 ............................................................................................................. 4 2.2 VHDL语言简介 ................................................................................................................ 4 2.3 Protel 99SE简介 .......................................................................................................... 5 第3章 系统硬件分析与设计 ....................................................................................................... 5 3.1 硬件电路系统 ................................................................................................................. 5 3.2 核心CPLD模块 ............................................................................................................... 6 3.1.1主要功能 ................................................................................................................ 6 3.1.2 芯片选择 ............................................................................................................... 6 3.3 液晶显示模块 ................................................................................................................. 7 3.3.1 主要功能 ............................................................................................................... 7 3.3.2 引脚分布及连接 ................................................................................................... 7 3.4 4*4键盘模块 .................................................................................................................. 8 3.4.1 主要功能 ............................................................................................................... 8 3.4.2 引脚分布及连接 ................................................................................................... 8 3.5 JTAG接口模块 ................................................................................................................ 8 3.5.1 主要功能 ............................................................................................................... 8 3.5.2 引脚分布及连接 ................................................................................................... 9 第4章 系统软件实现、仿真及结果分析 ................................................................................... 9 4.1 键盘输入模块 ................................................................................................................. 9 4.1.1 键盘输入实现过程 ............................................................................................... 9 4.1.2 键盘输入模块及其仿真 ..................................................................................... 10 4.1.3 键盘输入模块仿真结果分析 ............................................................................. 11 4.2 启动控制模块 ............................................................................................................... 11 4.2.1 启动控制实现过程 ............................................................................................. 11 4.2.2 启动控制模块及其仿真 ..................................................................................... 12 4.2.3 启动控制模块仿真结果分析 ............................................................................. 13 4.3 分频模块 ....................................................................................................................... 14 4.3.1 系统分频实现过程 ............................................................................................. 14 4.3.2 分频模块及其仿真 ............................................................................................. 15 4.3.3 分频模块仿真结果分析 ..................................................................................... 15 4.4 计时模块 ....................................................................................................................... 16 4.4.1 计时实现过程 ..................................................................................................... 16 4.4.2 计时模块及其仿真 ............................................................................................. 16