锁定键盘的程序

 

#include <reg51.h>

#include <absacc.h>

#define uchar unsigned char

#define uint unsigned int

void delays(void);

uchar kbscan(void);

main()

{

 

    bit CRT;                        /*密码正确标志，=1密码正确*/

    bit PRT;                        /*密码部分输入标志，=1密码部分输入*/

    uchar COUNT;                    /*计数单元，存放密码正确的位数*/

    uchar KEY;                  /*被按下的键的编码*/

 

    CRT=0;

    PRT=0;

    COUNT=0;

KEY=kbscan();                   /*键扫描函数*/

delays();                       /*键消抖的延时函数*/

    switch (KEY)

    {

        case 0xb7:              /*0键*/

        {

            if (CRT)

            {

               

            }

            else                                /*密码不正确时*/

            {

                if (PRT)                        /*部分密码正确时*/

                {

                    COUNT=COUNT+1;          /*密码正确的位数加1*/

                    if (COUNT==3)               /*密码所有位都正确*/

                    {

                        CRT=1;

                        PRT=0;

                        COUNT=0;

                    }                  

                }

            }

        }; break;              

        case 0x7e:                              /*1键*/

        {

            if (CRT)

            {

                                    /*密码正确时的操作内容*/

            }

            else                                /*密码不正确时*/

            {

                PRT=0;

                COUNT=0;

            }

        }; break;

        case 0xbe:                          /*2键*/

        {

            if (CRT)

            {

                                /*密码正确时的操作内容*/

            }

            else                            /*密码不正确时*/

            {

                if (PRT)                    /*部分密码正确时，说明密码错误*/

                {

                    PRT=0;

                    COUNT=0;

                }

                else                        /*密码正确位数为0时，说明密码第一位正确*/

                {

                    PRT=1;

                    COUNT=1;

                }

            }

        }; break;              

        case 0xd7:                      /*#键*/

        {

            if (CRT)                        /*密码正确时，锁定键盘*/

            {

                CRT=0;

                PRT=0;

                COUNT=0;

            }

        }; break;

                   

       

    }

}

 

// 键消抖的延时函数

void delays(void)

{

uchar i;

for(i=300;i>0;i--);

}

 

//  kbscan(void) 键扫描函数

uchar kbscan(void) 

{

uchar sccode,recode;

P1=0xf0;                                /*发全"0"行扫描码，列线输入*/

if((P1&0xf0)!=0xf0)                     /*若有键按下*/

{

delays();                           /*延时去抖动*/

if((P1&0xf0)!=0xf0)

{

sccode=0xfe;                    /*逐行扫描初值*/

while((sccode&0x10)!=0)

{

P1=sccode;                  /*输出行扫描码*/

if((P1&0xf0)!=0xf0)         /*本行有键按下*/

{

recode=(P1&0xf0)|0x0f;

return((~sccode)+(~recode)); /*返回特征字节码*/

}

else sccode=(sccode<<1)|0x01;   /*行扫描码左移一位*/

}

}

}

return(0);                              /*无键按下，返回值为0*/

}