基于ATmega168溫度控制器的軟件設(shè)計

摘    要

溫度是生活和生產(chǎn)中一個很重要的物理量，在很多領(lǐng)域都要涉及到溫度、如冶金工業(yè)、化工、生產(chǎn)、造紙行業(yè)、機械制造、電加熱爐及家用電器等，均需要用加熱器來加熱實驗對象，并對溫度進行測量和控制，使溫度這一被控對象達到并保持在某一設(shè)定的溫度范圍內(nèi)，即恒溫控制。然而，溫度控制系統(tǒng)具有非線性，時滯以及不確定性。
本次設(shè)計是基于AVR系列單片機ATmega168設(shè)計一種溫度控制器，其特點是具有液晶顯示，溫度在0℃到30℃范圍可調(diào)，并具有RS485總線接口，可以與上位機進行數(shù)據(jù)通信。其軟件方面的功能包括：系統(tǒng)初始化、液晶顯示驅(qū)動程序設(shè)計、按鍵和燃燒指示信號采集程序、溫度測量程序設(shè)計、控制邏輯的實現(xiàn)以及基于RS485串行的Modbus協(xié)議的實現(xiàn)等。
通過程序編寫和上機調(diào)試，實現(xiàn)了對溫度系統(tǒng)的控制要求。設(shè)計的軟件可以完成：對系統(tǒng)進行初始化；液晶顯示；采集按鍵和燃燒指示信號并進行反饋報警；測量環(huán)境溫度并進行溫度控制等功能。

關(guān)鍵詞：溫度控制系統(tǒng)  ATmega168單片機  I2C總線  Modbus協(xié)議

 
ABSTRACT
The temperature is life and production in a very important physics, in many areas to want to involve temperature, such as metallurgy industry, chemical industry, the production, the paper industry, machinery manufacturing, electric heating and household electric appliances, etc, all need to use the heater to heating experimental object and temperature measuring and control the temperature, the controlled object to attain and maintain a set in the temperature range, namely constant temperature control. However, the temperature control system with nonlinear, delay and uncertainty
 Based on the AVR series of SCM ATmega168 to design a gas radiant heating controller is the purpose of this design. Its characteristics are having a LCD, temperature range from 0 ℃ to 30 ℃ adjustable, having a bus interface with RS485, and being able to carry out data communication with PC. The software features include system initialization, LCD driver, buttons and burning direct signal acquisition program, temperature measurement program, the implementation of control logic and the implementation of Modbus protocol which is based on the serial RS485, etc.
Through programming and the debugging, the control requirements of gas radiant heating system are realized. The software can complete jobs as followed: system initialization, LCD, collecting buttons and burning direct signal and having the feedback alarms for burning direct signal, measuring temperature and controlling it, etc.

Keywords: temperature control system  SCM of ATmega168  I2C bus  Modbus protocol
 
目　　錄

1  前    言 1
2  單片機及相關(guān)協(xié)議 2
2.1  ATmega168單片機介紹 2
2.1.1　ATmega168單片機簡介 2
2.1.2　AVR CPU內(nèi)核 2
2.1.3　系統(tǒng)時鐘 4
2.1.4　兩線串行接口 5
2.2　I2C總線協(xié)議 6
2.2.1　I2C總線的概念 6
2.2.2　I2C總體特征 6
2.2.3　I2C總線規(guī)范 7
2.2.4　位傳輸 7
2.2.5　傳輸數(shù)據(jù) 8
2.2.6　7位尋址 9
2.3　Modbus協(xié)議 9
2.3.1　Modbus協(xié)議介紹 9
2.3.2　串行傳輸 11
2.3.3　Modbus信息幀 12
2.3.4　地址設(shè)置 12
2.3.5　功能碼 13
2.3.6　數(shù)據(jù)區(qū)的內(nèi)容 13
2.3.7　錯誤校驗 13
2.3.8　本控制器使用的Modbus功能代碼 13
3　編程及仿真軟件 17
3.1　ICCAVR軟件 17
3.1.1　ICCAVR軟件簡介 17
3.1.2　ICCAVR的IDE環(huán)境 17
3.2　AVRStudio軟件 17
4　控制器軟件設(shè)計 18
4.1　LCD驅(qū)動和按鍵處理程序 20
4.1.1　顯示器顯示控制 20
4.1.2　段碼驅(qū)動程序 21
4.1.3　液晶驅(qū)動控制 22
4.1.4　按鍵控制程序 23
4.1.5　控制功能實現(xiàn)程序 25
4.1.6　報警和消音邏輯程序 28
4.1.7　按鍵切換程序 30
4.1.8　綜合狀態(tài)處理程序 31
4.2　I2C功能實現(xiàn) 34
4.3　Modbus協(xié)議功能實現(xiàn) 36
4.3.1　基本功能 36
4.3.2　檢查UART0數(shù)據(jù) 39
4.4　初始化子程序 41
4.5　時間任務(wù)與處理 42
4.5.1　時間標志實現(xiàn) 42
4.5.2　任務(wù)處理 43
4.6　系統(tǒng)主程序 43
5　軟件調(diào)試 44
結(jié)    論 45
謝    辭 46
參考文獻 47