毕业论文 基于单片机的电子秤设计.doc
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毕业论文 基于单片机的电子秤设计,摘 要:本设计以51系列单片机stc89c52rc为控制核心，实现电子秤的基本控制功能。在设计系统时，为了更好地采用模块化设计法，分步的设计各个单元功能模块，系统的硬件部分可以分为最小系统、数据采集、人机交互界面(键盘以及显示)和系统电源四大部分。最小系统部分为stc89c52rc系统；数据采集部分由压力传感器、信号的...
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摘 要:本设计以51系列单片机STC89C52RC为控制核心，实现电子秤的基本控制功能。在设计系统时，为了更好地采用模块化设计法，分步的设计各个单元功能模块，系统的硬件部分可以分为最小系统、数据采集、人机交互界面(键盘以及显示)和系统电源四大部分。最小系统部分为STC89C52RC系统；数据采集部分由压力传感器、信号的前级处理和A/D转换部分组成，包括运算放大器OP07和A/D转换器ADC0809；人机交互界面为键盘输入和数码管显示，主要使用5X5键盘、CH423数码管控制芯片及13位数码管显示，可以方便的输入数据并直观的显示重量、单价和总价。系统电源是以LM7805、 LM7812为核心设计电路以提供系统正常工作电源。软件部分应用单片机C51语言进行编程，实现了该设计的基本控制功能。该电子秤可以实现基本的称重功能（称重范围为0～10Kg，重量误差不大于±0.02Kg）,重量、单价、总价的计量可以精确到两位小数，键盘设置有数字键（‘0’～‘9’、‘.’）、储存键、单价1～单价8调用单价键、清除键、去皮键等；发挥部分有8种不同物品的单价记忆功能、99种消费商品价格累计功能、；待发挥部分为讲电子秤与打印机连接，能打印消费记录（小票），超量程和欠量程的报警功能。本系统结构简单，使用方便，功能齐全，精度高，具有一定的开发价值。
关键词：单片机 采样电路A/D转换器 CH423数码管驱动芯片 数码管显示 工作电源
the design of electronic scales based on Single-chip Microcomputer
ABSTRACT :The design for the control of 51 computers STC89C52RC the core, to achieve the basic control functions of electronic scales. In designing the system, in order to better modular design, the design of each unit step function modules, the system can be divided into the minimum hardware system, data acquisition, man-machine interface (keypad and display) and the system power 4 most. Minimum system partly STC89C52RC system; data collection in part by the pressure sensor, signal processing and the first class A / D conversion components, including the operational amplifier OP07 and the A / D converter ADC0809; man-machine interface for the keyboard and digital display The main use of 5X5 keypad, CH423 digital control chip and 13 digital display, can easily enter data and visual display weight, unit price and total price. System power is based on LM7805, LM7812 as the core design of the circuit to provide normal power supply system. Software part of the application MCU C51 language programming, the design of the basic control functions. The electronic weighing scales can realize the basic functions (weighing range of 0 ~ 10Kg, the weight of the error is not greater than ± 0.02Kg), weight, unit price, total measurement is accurate to two decimal places, the keyboard settings are the number keys ( '0 '~ '9','.'), storage key, Unit 1 to Unit 8 Unit call key, clear key, peeled keys, etc.; play a part in 8 different items priced memory, 99 kinds of consumer goods prices cumulative function; play a part to be about electronic scales and printers connected to print consumption records (small notes), over range and under-range alarm. The system is simple, easy to use, fully functional, high precision, has some value for development.
Key words： microcontroller sampling circuit A/D converter CH423 digital tube driver chip digital display Power Supply
目录
第一章 绪 论 1
1.1引言 1
1.2 选题背景与意义 1
第二章 系统方案的设计 2
2.1 电子秤的设计要求 2
2.1.1 基本要求 2
2.1.2 特色与创新 2
2.2实验原理及设计基本思路 2
2.2.1系统工作原理 2
2.2.2 系统设计基本思路 2
2.3 系统总体设计方案比较与论证 3
2.4单片机的选型 4
2.5 数据采集部分的方案确定 4
2.5.1 传感器 4
2.5.2 前级放大器部分 7
2.5.3 A/D 转换器 9
2.6人机交互部分 11
2.6.1 键盘输入 11
2.6.2 输出显示 11
2.7系统电源 12
2.8 具体实施方案简介 13
第三章 系统硬件设计 15
3.1 基于STC89C52RC的主控电路 15
3.1.1芯片介绍 15
3.2 系统电源 18
3.2.1 芯片介绍 18
3.2.2 电源电路 19
第四章 软件流程 20
4.1 主程序流程图 20
4.2 键盘扫描流程图 21
第五章 结 论 22
5.1 论文总结 22
5.2 感想 22
致 谢 24
参 考 文 献 25
附录A：原理图 26
附录B：源程序 29
关键词：单片机 采样电路A/D转换器 CH423数码管驱动芯片 数码管显示 工作电源
the design of electronic scales based on Single-chip Microcomputer
ABSTRACT :The design for the control of 51 computers STC89C52RC the core, to achieve the basic control functions of electronic scales. In designing the system, in order to better modular design, the design of each unit step function modules, the system can be divided into the minimum hardware system, data acquisition, man-machine interface (keypad and display) and the system power 4 most. Minimum system partly STC89C52RC system; data collection in part by the pressure sensor, signal processing and the first class A / D conversion components, including the operational amplifier OP07 and the A / D converter ADC0809; man-machine interface for the keyboard and digital display The main use of 5X5 keypad, CH423 digital control chip and 13 digital display, can easily enter data and visual display weight, unit price and total price. System power is based on LM7805, LM7812 as the core design of the circuit to provide normal power supply system. Software part of the application MCU C51 language programming, the design of the basic control functions. The electronic weighing scales can realize the basic functions (weighing range of 0 ~ 10Kg, the weight of the error is not greater than ± 0.02Kg), weight, unit price, total measurement is accurate to two decimal places, the keyboard settings are the number keys ( '0 '~ '9','.'), storage key, Unit 1 to Unit 8 Unit call key, clear key, peeled keys, etc.; play a part in 8 different items priced memory, 99 kinds of consumer goods prices cumulative function; play a part to be about electronic scales and printers connected to print consumption records (small notes), over range and under-range alarm. The system is simple, easy to use, fully functional, high precision, has some value for development.
Key words： microcontroller sampling circuit A/D converter CH423 digital tube driver chip digital display Power Supply
目录
第一章 绪 论 1
1.1引言 1
1.2 选题背景与意义 1
第二章 系统方案的设计 2
2.1 电子秤的设计要求 2
2.1.1 基本要求 2
2.1.2 特色与创新 2
2.2实验原理及设计基本思路 2
2.2.1系统工作原理 2
2.2.2 系统设计基本思路 2
2.3 系统总体设计方案比较与论证 3
2.4单片机的选型 4
2.5 数据采集部分的方案确定 4
2.5.1 传感器 4
2.5.2 前级放大器部分 7
2.5.3 A/D 转换器 9
2.6人机交互部分 11
2.6.1 键盘输入 11
2.6.2 输出显示 11
2.7系统电源 12
2.8 具体实施方案简介 13
第三章 系统硬件设计 15
3.1 基于STC89C52RC的主控电路 15
3.1.1芯片介绍 15
3.2 系统电源 18
3.2.1 芯片介绍 18
3.2.2 电源电路 19
第四章 软件流程 20
4.1 主程序流程图 20
4.2 键盘扫描流程图 21
第五章 结 论 22
5.1 论文总结 22
5.2 感想 22
致 谢 24
参 考 文 献 25
附录A：原理图 26
附录B：源程序 29
