【正文】 用也越來越廣泛。傳統(tǒng)的機械式 定時器，電動式定時器都是通過發(fā)條、交流同步步進(jìn)電機或者石英步進(jìn)電機進(jìn)行驅(qū)動的。相對于前兩種定時器，電子式定時器體積小、重量輕、造價低、精度高、壽命長、而且安全可靠、調(diào)整方便、適于頻繁使用。 本文設(shè)計了一種以TMS320F28335 DSP 微控制器 為核心的定時器。 通過 SPI 串行外設(shè)接 口在 DSP 和74HC164 之間進(jìn)行通信，進(jìn)而 實現(xiàn)在數(shù)碼管上 通過動態(tài)掃描 顯示定時時間 。 在定時器 暫停時 ，還可以通過鍵盤 重新輸入 定時 初值 。 關(guān)鍵詞： 定時器 ， DSP， TMS320F28335 ， 串行外設(shè) 接口 ，矩陣鍵盤 第 2 頁 Abstract With the progress of the times and the development of electronic industry, the timer is used more and more widely. The traditional mechanical timer, electric timer is drived through the spring, AC synchronous motor or quartz stepper motor .The accuracy of this timer is not high and the error is large. Compared with the former two timer, electroni c timer has small volume, light weight, low cost, high precision, long service life, and electronic timer is safety and reliability, convenient adjustment, suitable for frequent use. The topic of this design is timer design based on the DSP paper designs a timer with the core of TMS320F28335 DSP microcontroller. Generating a timer interrupt and counting retrogradely by using the internal timer 0 and PIE peripheral interrupt expansion module. Communicate between DSP and 74HC164 through the SPI serial peripheral interface, so as to achieve displaying time on the digital tube by dynamic scanning. The system is turned on and paused through the matrix keyboard. In the timer pause,initial value can be inputed through the keyboard . When the timing is over, system will alarm through LED lights flashing, prompting the end of timing. Key Words: timer ,DSP ,TMS320F28335 ,SPI, matrix keyboard 第 3 頁 目 錄 1 緒論 .......................................................................................................................... 1 系統(tǒng)背景 ........................................................................................................ 1 定時器的分類 .................................................................................... 1 定時器的應(yīng)用 .................................................................................... 2 定時器系統(tǒng)概述 ........................................................................................... 2 定時器設(shè)計及實現(xiàn)的功能 ........................................................................... 2 設(shè)計過程 ............................................................................................ 2 定時器方案的確定 ............................................................................ 3 定時器的功能 .................................................................................... 3 2 定時器系統(tǒng)的硬件設(shè)計 .......................................................................................... 4 總體硬件設(shè)計 ............................................................................................... 4 DSP 微控制器 ............................................................................................... 5 定時器中斷的實現(xiàn) ........................................................................................ 6 DSP 內(nèi)部定時器 ................................................................................ 6 PIE 外設(shè)中斷擴展模塊 ...................................................................... 7 數(shù)碼管顯示電路 ........................................................................................... 8 SPI 串行外設(shè)接口 .............................................................................. 9 74HC164 ........................................................................................... 12 數(shù)碼管 .............................................................................................. 13 按鍵控制電路 .............................................................................................. 16 第 4 頁 矩 陣鍵盤的概述 .............................................................................. 16 矩陣鍵盤的硬件設(shè)計 ...................................................................... 16 按鍵接口的消抖 .............................................................................. 17 LED 顯示電路 ............................................................................................. 18 3 定時器軟件的設(shè)計 ................................................................................................ 19 主函數(shù)程序設(shè)計 ......................................................................................... 19 SPI 的初始化 ............................................................................................... 19 定時器、數(shù)碼管，按鍵及其他外設(shè)的初始化 ......................................... 21 定時器的初始化 .............................................................................. 21 其他外設(shè)的初始化 .......................................................................... 21 cpu 中斷及其 PIE 的設(shè)置 ........................................................................... 22 設(shè)置定時器 0 的周期、打開定時器、看門狗和開中斷 ......................... 22 設(shè)定定時器的周期 .......................................................................... 22 打開定時器 ...................................................................................... 22 開中斷 .............................................................................................. 23 開啟看門狗 ...................................................................................... 23 主要功能的實現(xiàn) ......................................................................................... 23 定時器中斷子程序的設(shè)計 .............................................................. 23 SPI 通信與數(shù)碼管顯示程序的設(shè)計 ................................................ 24 矩陣鍵盤程序設(shè)計 ........................................................................... 26 核心功能的設(shè)計 .............................................................................. 29 4 總結(jié) ........................................................................................................................ 33 第 5 頁 參考文獻(xiàn) .................................................................................................................... 34 致謝 ..........