嘉应学院单片机考试程序.doc

第四章实例1：独立按键识别#includevoid main() char key = 0; P2=0; while(1) key = P0 & 0x0f; /读取按键状态,高4位清零 if (key != 0) P2 = key; /有按键动作时，P0状态值送P2 实例2：键控流水灯#includeunsigned char led =0x01,0x02,0x04,0x08;void delay(unsigned char time)unsigned char j=225;for(;time0;time- -)for(;j0;j- -);void main()bit dir=0,run=0;unsigned char i;while(1)switch (P0 & 0x0f)case 0x0e:run=1;break;case 0x0d:run=0,dir=1;break;case 0x0b:dir=1;break;case 0x07:dir=0;break;if(run)if(dir)for(i=0.i=0;i- -)P2=ledi;delay(200);else P2=0;实例4：LED数码管显示#includechar led_mod=0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f;void delay(unsigned int time)unsigned int j=0;for(;time0;time- -)for(j=0;j125;j+);void main(void)char i=0;while(1)for(i=0;i=9;i+);delay(500);实例5：#includesbit P3_7=P37;unsigned char code table=0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f;unsigned char count;void delay(unsigned int time)unsigned int j=0;for(;time0;time-) for(j=0;j125;j+);void main(void) count=0;P0=tablecount/10;P2=tablecount%10;while(1) if(P3_7=0)delay(10);if(P3_7=0)count+;if(count=100) count=0; P0=tablecount/10; P2=tablecount%10; while(P3_7=0);实例7：行列式键盘编程 #include char led_mod = 0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x58,0x5e,0x79,0x71 ;char key_buf = 0xee,0xde,0xbe,0x7e,0xed,0xdd,0xbd,0x7d,0xeb,0xdb,0xbb,0x7b,0xe7,0xd7,0xb7,0x77;void getKey(void)char key_scan=0xef,0xdf,0xbf,0x7f;char i=0,j=0;for(i=0;i4;i+)P3= key_scani;if（P3!=0xff) for(j=0;j16;j+)if(key_bufj=P3) return j;return=-1; void main(void)char key=0; P2=0x00;while(1) key=getKey(); if(key!=-1)P2=led_modkey; 第五章实例1 单片机开关状态检测在单片机的INT0端口接一开关，P1.0口接一发光二极管。每次开关闭合（接地）时，发光二极管改变一次状态。程序如下#includesbit P1_0=P10;int0_srv()interrupt 0P1_0=!P1_0;void main()IT0=1;EX0=1;EA=1;while(1);实例2 中断扫描法行列式键盘#include char led_mod = 0x3f，0x06，0x5b，;char key_buf = 0x11, ;void getKey() interrupt 0char key_scan=0xef,0xdf,0xbf,0x7f;char i=0,j=0;for(i=0;i4;i+)P1= key_scani;for(j=0;j16;j+)if(key_bufj=P1)P2=led_modj;break;void main(void)P2=0x00;IT0=1;EX0=1;EA=1;while(1)P1=0x0f;实例3：中断方式的键控流水灯#includechar led =0x01,0x02,0x04,0x08;bit dir=0,run=0;void delay(unsigned char time);key() interrupt 0switch (P0 & 0x0f)case 0x0e:run=1;break;case 0x0d:run=0,dir=1;break;case 0x0b:dir=1;break;case 0x07:dir=0;break;void main()char i;IT=1;EX0=1;EA=1;while(1)if(run)if(dir)for(i=0.i=0;i- -)P2=ledi;delay(200);else P2=0;void delay(unsigned char time)unsigned int j=0;for(;time0;time- -)for(j=0;j125;j+);实例4：根据电路图编程验证两级外部中断嵌套效果#includechar led_mod=0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f;sbit D1=P30;void delay(unsigned int time)unsigned char j=0;for(j=255;time0;time- -)for(;j0;j- -);key0() interrupt 0unsigned char i;D1=IE0;for(i=0.i=9;i+)P2=led_modi;delay(35000);P2=0x40;Key1() interrupt 2unsigned char i;D1=IE0;for(i=0.i=9;i+)P1=led_modi;delay(35000);P2=0x40;void main () unsigned char i;TCON=0x05;PX0=0;PX1=1;D1=0;P1=P2=0x40;IE=0x85;while(1)for(i=0.i=9;i+)P2=led_modi;delay(35000);第六章实例1：单片机晶振频率12MHz，应用定时器/计数器0方式1产生1ms 的定时，并使P1.0输出周期为2ms的方波。（此题可分为用中断方式和查询方式）。查询方式#include sbit P1_0 = P10;main () TMOD = 0x01; /设置T0定时方式1(0000 0001B) TR0=1; /启动T0 for(;) TH0 = -(1000/256); /装载计数初值 TL0 = -(1000%256); do while(!TF0); /查询等待TF0复位 P1_0 =!P1_0; /定时时间到P1.0反相 TF0 = 0; /TF0标志清0（b）中断方式#include sbit P1_0=P10;void timer0 (void) interrupt 1 using 1 P1_0 = !P1_0; /P1.0取反 TH0 = -(1000/256); /装载计数初值 TL0 = -(1000%256);void main (void) TMOD = 0x01; /T0定时方式1 P1_0-0; TH0 = -(1000/256);/装载计数初值 TL0 = -(1000%256); EA=1; /开总中断 ET0=1; /开T0中断 TR0=1; /启动T0do while(1);实例3：设计一个波形展宽程序。设由P3.4输入一个低频窄脉冲信号。当P3.4波形发生负跳变时，由P3.0口输出一个500s宽的同步脉冲（设系统频率为6MHz）。:#include sbit P3_0=P30;void main () TMOD = 0x06; /设置为T0计数方式2 TL0 = 255;/初值0xff可使1个外来脉冲即产生溢出 TR0 = 1;/启动计数器 while (1) while (!TF0);/等待首次溢出 TF0 = 0;/清TF0溢出标志 TMOD = 0x02; /设置为T0定时方式2 TH0 = -250;/6MHz频率500ms定时初值 TL0 = -250; P3_0 = 0; while (!TF0);/等待再次溢出 TF0 = 0;/清TF0溢出标志 P3_0 = 1; TMOD = 0x06;/设置为T0计数方式2 TL0 = 255;/重新置初值 实例4 采用10MHz晶振，在P1.0脚上输出周期为2.5s，占空比为20%的脉冲信号。该题电路图与实例1相同。10毫秒10MHz的计数初值为：a = - tfosc/12 = -1000010/12=-8333 #include #defineucharunsignedchar uchar time; uchar period=250; uchar high=50;timer0 (void) interrupt 1 using 1 TH0= -8333/256; /重载计数初值 TL0= -8333%256; if (+time= =high) P1=0; /高电平时间到变低 else if (time= =period) /周期时间到变高 time=0; P1=1;main ( ) TMOD=0x01; /T0方式1 TH0= -8333/256; /计数初值 TL0= -8333%256; EA=1; ET0=1; TR0=1; do while (1);实例5：采用定时中断方式，实现下图跑马灯控制功能。要求跑马灯的闪烁速率为每秒1次。#define uchar unsigned char /定义下一个方便后面使用#include /包括一个51标准内核的头文件bit ldelay-0; /长定时溢出标志Uchar t=0; /定时溢出次数void main(void) /主程序uchar code ledp8=0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f; /跑马灯工作状态uchar ledi; /用来指示显示顺序TOMD=0x01; /定义T0，方式1TH0=0x3c; /T0初值，溢出20次为1s（按12MHz晶振计算）TL0=0xb0;TR0=1; /启动定时器ET0=1; /打开定时器0中断EA=1; /打开总中断While(1) /主程序循环If(ldelay) /发现有时间溢出，进入处理ldelay=0; /清除标志P2=ledpledi; /读出一个值送到P2口Ledi+; /指向下一个If(ledi=8)ledi=0; /到了最后一个灯就换到第一个/定时器0中断函数timer0 () interrupt 1t+;if(t=20)t=0;ldelay=1; /每次溢出一个标志，以便主程序处理TH0=0x3c; /重置T0初值TL0=0xb0;实例6 通过T0对虚拟脉冲信号发生器的脉冲进行计数，并在共阳型LED数码管上动态显示出来。解: 程序如下。#include #define uchar unsigned char#define uint unsigned int uchar BitTab=0x20,0x10,0x08,0x04,0x02,0x01 ;/LED位驱动码uchar DispTab=0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90,0x88,0x83,0xC6,0xA1,0x86,0x8E,0xFF;/LED字形码uchar DispBuf6; /显示缓冲区/-定时器0中断处理程序-void Timer1(void) interrupt 3 uchar tmp; uchar Count; /计数器，显示程序通过它得知现正显示哪个数码管 TH1=(65536-3000)/256; TL1=(65536-3000)%256; /重置初值 tmp=BitTabCount; /取位值 P2=P2|0xfc; /P2与11111100B相或 P2=P2&tmp; /P2与取出的位值相与 tmp=DispBufCount;/取出待显示的数 tmp=DispTabtmp;/取字形码 P0=tmp; Count+; if(Count=6) Count=0; void main () uint tmp; P1=0xf