課堂教學(xué)教案

1、課堂教學(xué)教案授課章節(jié)名稱波形發(fā)生器的程序設(shè)計(jì)課型新授授課日期年 月日第周課時(shí)數(shù)4教學(xué)目標(biāo)1、進(jìn)一步穩(wěn)固了解數(shù)模轉(zhuǎn)換器的使用原理2、掌握波形發(fā)生器方波、正弦波的產(chǎn)生方法及其原理3、培養(yǎng)學(xué)生的自學(xué)意識(shí)教學(xué)重點(diǎn)方波、正弦波的模擬生成方法教學(xué)難點(diǎn)方波、正弦波的模擬生成方法教學(xué)方法講授法、小組討論法教學(xué)資源PPT仿真電路課外作業(yè)完成工程實(shí)訓(xùn)任務(wù)教學(xué)后記點(diǎn)的形成：at89s51向DAC0832傳送不同的數(shù)字編碼,產(chǎn)生不同的輸出。語(yǔ)句“ dacio= OxFF; 把OxFF寫(xiě)入DAC存放器，由運(yùn)算器輸出5V。語(yǔ)句“ dacio= 0x00; 把0x00寫(xiě)入DAC存放器，由運(yùn)算器輸出0V。r11«,

2、、r11- - 5Vlinea(OXFF), d .s»14i4aaii4a»i40V » 1 , , OXODntijiii>j v jkbr i教師講授復(fù)習(xí)模擬生成方法教師提問(wèn)學(xué)生記錄分析產(chǎn)生過(guò)程線的形成：連續(xù)輸出OxFF,在示波器的顯示窗口就可以觀察 到高電平的波形。連續(xù)輸出0x00，在示波器的顯示窗口就可以觀察 到低電平的波形。方波即由 AT89S51對(duì)P0 口不斷交替輸出 0x00和 0xFF周期確實(shí)立假設(shè)255個(gè)點(diǎn)構(gòu)成波形的一學(xué)生操作個(gè)周期，那么DAC0832輸出255個(gè)樣值點(diǎn)后，樣值點(diǎn) 形成運(yùn)動(dòng)軌跡，即一個(gè)周期。重復(fù)輸出255個(gè)點(diǎn)，成為第二個(gè)周

3、期。5V* (QXBm1272550LOV* (DXOT)#i nclude"reg51.h"#in elude"absacc.h"#defi ne dacio XBYTE0X7FFFvoid delay();mai n()un sig ned char i;while(1)教師提問(wèn)for(i=0;i<256;i+)if(i<127)dacio=0xff;elsedacio=0x00;delay();任務(wù)三設(shè)計(jì)程序控制輸出三角波先對(duì)各波形進(jìn)行抽樣，然后把各采樣值進(jìn)行編碼，得到的數(shù)字量經(jīng)過(guò) D/A轉(zhuǎn)換后輸出就可以得到波形。學(xué)生記錄三角波是由 A

4、T89S51對(duì)P0 口輸出0x00,在每一個(gè)時(shí)鐘到來(lái)時(shí)對(duì)輸出值加1 ；當(dāng)加至0xFF時(shí)，繼而在時(shí)鐘來(lái)臨時(shí)減1，這樣往復(fù)執(zhí)行，最終輸出近似連續(xù)的三角波。修改方波程序，實(shí)現(xiàn)三角波的輸出學(xué)生討論分析#in elude "reg51.h"#in elude "absacc.h"#defi nedacio XBYTE0X7FFFvoid delay();mai n( )un sig ned char i;while(1)梯形波由 AT89S51對(duì)P2 口輸出0x00,經(jīng)過(guò)一個(gè)時(shí)間段，輸出值增加0x19，完成一個(gè)10級(jí)的波形后再歸零，這樣往復(fù)執(zhí)行，最終輸出近似連續(xù)的

5、梯形波。修改方波程序，實(shí)現(xiàn)梯形波的輸出正弦波是將0x00到0xFF按照正弦波波形的變化趨勢(shì)分成255個(gè)間斷的點(diǎn)，形成一個(gè)正選波取值表，用AT89S51在每一個(gè)時(shí)鐘到來(lái)時(shí)取表值通過(guò)P0 口送至D/A0832轉(zhuǎn)換輸出。執(zhí)行程序時(shí)通過(guò)引用數(shù)組的方法依次取出曲線圖的數(shù)字量，經(jīng)過(guò)D/A轉(zhuǎn)換后輸出就可以得到波形。假設(shè)255個(gè)點(diǎn)構(gòu)成波形的一個(gè)周期，那么DAC0832輸出255個(gè)樣值點(diǎn)后，樣值點(diǎn)形成運(yùn)動(dòng)軌跡，即一個(gè)周期。重復(fù)輸出255個(gè)點(diǎn)，成為第二個(gè)周期。code char sin _data256=0x80,0x83,0x86,0x89,0x8c,0x8f,0x92,0x95,0x98,0x9c,0 x9f

6、,0xa2,0xa5,0xa8,0xab,0xae,0xb0,0xb3,0xb6,0xb9,0x bc,0xbf,0xc1,0xc4,0xc7,0xc9,0xcc,0xce,0xd1,0xd3,0xd 5,0xd8,0xda,0xdc,0xde,0xe0,0xe2,0xe4,0xe6,0xe8,0xea, 0xec,0xed,0xef,0xf0,0xf2,0xf3,0xf4,0xf6,0xf7,0xf8,0xf9 ,0xfa,0xfb,0xfc,0xfc,0xfd,0xfe,0xfe,0xff,0xff,0xff,0xff,0 xff,0xff,0xff,0xff,0xff,0xff,0xff

7、,0xfe,0xfe,0xfd,0xfc,0xfc學(xué)生總結(jié)并完成程序,0xfb,0xfa,0xf9,0xf8,0xf7,0xf6,0xf5,0xf3,0xf2,0xf0,0xe f,0xed,0xec,0xea,0xe8,0xe6,0xe4,0xe3,0xe1,0xde,0xdc, 0xda,0xd8,0xd6,0xd3,0xd1,0xce,0xcc,0xc9,0xc7,0xc4,0 xc1,0xbf,0xbc,0xb9,0xb6,0xb4,0xb1,0xae,0xab,0xa8,0x a5,0xa2,0x9f,0x9c,0x99,0x96,0x92,0x8f,0x8c,0x89,0x8 6,

8、0x83,0x80,0x7d,0x79,0x76,0x73,0x70,0x6d,0x6a,0x6 7,0x64,0x61,0x5e,0x5b,0x58,0x55,0x52,0x4f,0x4c,0x49 ,0x46,0x43,0x41,0x3e,0x3b,0x39,0x36,0x33,0x31,0x2e, 0x2c,0x2a,0x27,0x25,0x23,0x21,0x1f,0x1d,0x1b,0x19,0 x17,0x15,0x14,0x12,0x10,0xf,0xd,0xc,0xb,0x9,0x8,0x7, 0x6,0x5,0x4,0x3,0x3,0x2,0x1,0x1,0x0,0x0,0x0,0x0,0x0, 0x0,0x0,0x0,0x0,0x0,0x0,0x1,0x1,0x2,0x3,0x3,0x4,0x5, 0x6,0x7,0x8,0x9,0xa,0xc,0xd,0xe,0x10,0x12,0x13,0x15 ,0x17,0x18,0x1a,0x1c,0x1e,0x20,0x23,0x25,0x27,0x29, 0x2c,0x2e,0x30,0x33,0x35,0x38,0x3b,0x3d,0x40,0x43, 0x46,0x48,0x4b,