电子信息工程毕业论文 基于STC12C5A32S2单片机的电子计价秤设计.docVIP

基于STC12C5A32S2单片机的电子计价秤 摘要：秤是一种古老的重量计量衡器，在千百年的社会发展中，秤也随之不断发展，而在当代社会，随着社会要求的提高，传统的杆秤，天平称已不能很好地满足人们日常生活的需求。近几十年来，伴随着科学技术的巨大发展，电子衡器应运而生，凭借其装置简单，体积小，重量轻，称量范围大，保养简单，称量速度快，准确度高，自动化控制，功能强，操作简单等诸多优点，广泛地应用于市场交易、工业生产、日常生活当中。本电子计价秤设计基于STC12C5A32S2单片机，量程为0～3千克。将桥式电阻应变式传感器输出的电压，经前置信号放大电路放大，利用单片机内置的10位高速A/D转换器，转换为相应的数字信号，通过系统软件处理，在1602液晶显示屏上显示所称得的重量，单片机读取重量并显示后，用户可以通过按键输入所称量物品的单价，确定输入之后即可算得本次称量所得物品的金额。通过单价设置按键，可存储3种常用物品的单价，方便以后称重的时候使用快捷键进行快速操作。 关键词：电子计价秤STC12C5A32S2单片机差分放大  Electronic Cashier Scale Based on STC12C5A32S2 Abstract: The scale is a ancient tool for weighing, it was develop continuously with the society’s developing in the past thousand years. In nowadays, the traditional scale can’t satisfied with people because people’s high request. The electronic scale developed because of the technical develop in the past decades and applied widly such as saling, industry, daily life and so on. As scale is simple and small instrument,it was used widly for weighing. This electronic price computing scale is based on STC12C5A32S2, change the voltage signal which come from the sensor amplified by the Pre-signal amplification circuit to the digital signal using it’s inner 10-bit high speed A/D counter . The digital signal will be dealt by the program in the MCU, then displayed the weight of the object on the 1602LCD. The range of weighing between 0 to 3 Kg. After 1602LCD display the object’s weight, user can input the price of the object through keyboard, then the value of the object will be calculated and displayed. And in the keyboard, there are 3 keys which can operate to memory 3 price used frequently, if user want to input these prices, they can press the shortcuts, it can save much time instead of input the price one key by one key. Key word: electronic price computing scale, STC12C5A32S2, differential amplifier 目 录 第一章 绪论 1 第二章 系统概述 3 2.1 设计内容与要求 3 2.2 系统硬件分析 3 第三章 系统硬件设计 5 3.1 系统总体设计 5 3.2 单片机应用 5 3.2.1 单片机选型 5 3.2.2 STC12C5A32S2单片机简介 6 3.2.3 单片机电路设计 7 3.3 HL-8型称重传感器简介