单片机--key

来源：互联网发布：js for循环是什么作用编辑：程序博客网时间：2024/05/21 23:33

矩阵键盘

矩阵键盘用来控制功能的选择
按键的返回值又分为物理键值和逻辑键值，物理键值是按键实际的01代码，而逻辑键值是01代码翻译而来的十进制数。

key.c

#include "myhead.h"unsigned char key_scan(void)//返回按键的物理键值{    unsigned char keyvalue;    KEYPORT = 0xf0;    if(0xf0 != KEYPORT)//有按键按下    {        delay_ms(10);        if(0xf0 != KEYPORT)//确实有按键按下        {            KEYPORT = 0xfe;            if(0xfe != KEYPORT)            {                keyvalue = KEYPORT;                keyvalue &= 0xf0;                keyvalue += 0x0e;                while(0xfe != KEYPORT);                //有按键抬起                delay_ms(10);                while(0xfe != KEYPORT);                //确实有按键抬起                return keyvalue;                            }            KEYPORT = 0xfd;            if(0xfd != KEYPORT)            {                keyvalue = KEYPORT;                keyvalue &= 0xf0;                keyvalue += 0x0d;                while(0xfd != KEYPORT);                //有按键抬起                delay_ms(10);                while(0xfd != KEYPORT);                //确实有按键抬起                return keyvalue;            }                       KEYPORT = 0xfb;            if(0xfb != KEYPORT)            {                keyvalue = KEYPORT;                keyvalue &= 0xf0;                keyvalue += 0x0b;                while(0xfb != KEYPORT);                //有按键抬起                delay_ms(10);                while(0xfb != KEYPORT);                //确实有按键抬起                return keyvalue;            }               KEYPORT = 0xf7;            if(0xf7 != KEYPORT)            {                keyvalue = KEYPORT;                keyvalue &= 0xf0;                keyvalue += 0x07;                while(0xf7 != KEYPORT);                //有按键抬起                delay_ms(10);                while(0xf7 != KEYPORT);                //确实有按键抬起                return keyvalue;            }           }    }    return 0x00;}// unsigned char key_pro()//返回按键的逻辑键值// {//  unsigned char keynum;//  keynum = key_scan();//  switch(keynum)//  {//      case 0x7e :return 0;break;//      case 0xbe :return 1;break;//      case 0xde :return 2;break;//      case 0xee :return 3;break;//      case 0x7d :return 4;break;//      case 0xbd :return 5;break;//      case 0xdd :return 6;break;//      case 0xed :return 7;break;      //      case 0x7b :return 8;break;//      case 0xbb :return 9;break;//      case 0xdb :return 10;break;//      case 0xeb :return 11;break;//      case 0x77 :return 12;break;//      case 0xb7 :return 13;break;//      case 0xd7 :return 14;break;//      case 0xe7 :return 15;break; //     default:return 16;break;     //  }// }

此处将逻辑键值注释掉是因为，我在编译代码下载到51板子上时，代码总量超过了51单片机的最大容量，所以在程序中直接选用物理键值。

key.h

#ifndef _KEY_H#define _KEY_Hextern unsigned char key_scan(void);extern unsigned char key_pro();#endif

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