systwo.c

单片机系统实验环境程序

#include <absacc.h>
#include <reg51.h>
#include<intrins.h>

#define uchar unsigned char


#define LED5 XBYTE [0xA000]   //数码管地址
#define LED6 XBYTE [0xA001]
#define LED7 XBYTE [0xA002]
#define LED8 XBYTE [0xA003]
#define LED1 XBYTE [0xA004]
#define LED2 XBYTE [0xA005]
#define LED3 XBYTE [0xA006]
#define LED4 XBYTE [0xA007]

#define KEY XBYTE [0xA100]  //键盘地址




/*扫描键盘使用的变量 */
sbit first_row = P1^4;      //键盘第一行控制
sbit second_row = P1^3;     //键盘第二行控制
bit first_getkey = 0,control_readkey = 0;  //读键盘过程中的标志位
bit getkey = 0; //获得有效键值标志位 等于1时代表得到一个有效键值
bit keyon = 0;  //防止按键冲突标志位
uchar keynum = 0;  //获得的有效按键值寄存器 


/*数码管显示使用的变量和常量*/
uchar lednum = 0;  //数码管显示位控制寄存器
uchar led[8] = {0,0,0,0,0,0,0,0};  //数码管显示内容寄存器
uchar code segtab[18] = {0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0x88,0x83,0xc6,0xa1,0x86,0x8e,0x8c,0xff}; //七段码段码表
                      // "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "P" ,"black" 


void leddisp(void); //数码管显示函数
void readkey(void); //读键盘函数



void intT0() interrupt 1 //T0 定时中断处理函数
{
	TH0 = -2720/256;  //定时器中断时间间隔 4ms
 	TL0 = -2720%256;

 	leddisp();  //每次定时中断显示更新一次

 	if(control_readkey == 1)  //每两次定时中断扫描一次键盘
   	{
    	readkey();
   	}
 	control_readkey = !control_readkey;
}


void main(void)
{

	TMOD = 0x01;    //
 	TH0 = -2720/256;  //定时器中断时间间隔 4ms
 	TL0 = -2720%256;
	TCON = 0x10;
 	ET0 = 1;
 	EA = 1;

	
	while(1)
	{
 		if(getkey == 1)  //判断是否获得有效按键
  	    	{
     			getkey = 0;

  			led[0] = keynum;  //当按下其他按键时，全部数码管显示按键值
     			led[1] = keynum;  
    	    		led[2] = keynum;
     			led[3] = keynum;
     			led[4] = keynum;
     			led[5] = keynum;
     			led[6] = keynum;
     			led[7] = keynum;
   
     		}
 	}
}

/***************************************************
			键盘扫描函数
原型:   void readkey(void);
功能:  当获得有效按键时,令getkey=1，keynum为按键值

****************************************************/
void readkey(void)
{
	uchar M_key = 0;  

 	first_row = 0;
 	second_row = 0;
 	M_key = KEY;
 	if(M_key != 0xff)  //如果有连续两次按键按下，认为有有效按键按下。消除按键抖动
   	{
    		if(first_getkey == 0)
     		{
   			first_getkey = 1;	
   		}
  		else    //当有有效按键按下时，进一步识别是哪一个按键
   		{
   			if(keyon == 0)  //防止按键冲突，当还有未释放的按键时不对其它按键动作响应   
   			{
      				first_row = 0;         //扫描第一行按键
      				second_row = 1;
         			M_key = KEY;
         			if(M_key != 0xff)
           			{
            				switch(M_key) 
            				{	
            	 				case 0xfe:
                   					keynum = 0x00;
               						break;
            					case 0xfd:
                       					keynum = 0x01;
                 					break;
               					case 0xfb:
                 		    			keynum = 0x02;
                 					break;
               					case 0xf7:
                      					keynum = 0x03;
                 					break;
               					case 0xef:
                 					keynum = 0x04;
                 					break;
               					case 0xdf:
                 					keynum = 0x05;
                					break;
               					case 0xbf:
                					keynum = 0x06;
                 					break;
              	 				case 0x7f:
                 					keynum = 0x07;
                 					break;
              				}
           			}
         			else
           			{
            				second_row = 0;     //扫描第二行按键
            				first_row = 1;
            				M_key = KEY;
            				switch(M_key)
              				{
               					case 0xfe:
                					keynum = 0x08;
                					break;
               					case 0xfd:
                 					keynum = 0x09;
                 					break;
               					case 0xfb:
                 					keynum = 0x0a;
                 					break;
               					case 0xf7:
                 					keynum = 0x0b;
                 					break;
               					case 0xef:
                 					keynum = 0x0c;
                 					break;
               					case 0xdf:
                 					keynum = 0x0d;
                 					break;
               					case 0xbf:
                 					keynum = 0x0e;
                 					break;
               					case 0x7f:
                 					keynum = 0x0f;
                 					break;
              				}
           			}
				getkey = 1; //获得有效按键数值
                		keyon = 1;  //防止按键冲突，当获得有效按键时将其置1
        		} 
     		} 
   	}
 	else
   	{
    		first_getkey = 0;
    		keyon = 0;     //防止按键冲突，当所有的按键都释放时将其清0
    	}
}

/***************************************************
			数码管显示函数
原型:   void leddisp(void);
功能:  每次调用轮流显示一位数码管

****************************************************/
void leddisp(void)
{
	switch(lednum)  //选择需要显示的数码位
 	{
  		case 0:
    		LED1 = segtab[led[0]];
     		break;
  		case 1:
     		LED2 = segtab[led[1]];
     		break;
 		case 2:
     		LED3 = segtab[led[2]];
     		break;
 		case 3:
     		LED4 = segtab[led[3]];
     		break;
 		case 4:
     		LED5 = segtab[led[4]];
     		break;
 		case 5:
     		LED6 = segtab[led[5]];
     		break;
 		case 6:
     		LED7 = segtab[led[6]];
     		break;
		case 7:
     		LED8 = segtab[led[7]];
     		break;
  	}

	if(lednum == 0) //更新需要现实的数码位
 	{
		lednum = 7;
 	}
 	else
 	{
		lednum = lednum-1;
	}
}