特點：

按鍵在松手後有(yǒu)效,靈敏度高(gāo),消耗資源少(shǎo),運行(xíng)效率高(gāo)

獨立鍵盤為(wèi):K01=P2^4;K02=P2^5;K03=P2^6;K04=P2^7;

矩陣鍵盤為(wèi):行(xíng)(上(shàng)到下)_P2.3_P2.2_P2.1_P2.0

           列(左到右)_P2.7_P2.6_P2.5_P2.4

提供的操作(zuò)函數(shù)：

//獨立鍵盤.無按鍵動作(zuò)時(shí)其返回值num_key=0,否則返回按鍵号num_key

extern unsigned char keyboard_self();

//矩陣鍵盤.無按鍵動作(zuò)時(shí)其返回值num_key=0,否則返回按鍵号num_key****檢測高(gāo)四位

extern unsigned char keyboard_matrix();

****************************************/

先看獨立鍵盤（和(hé)矩陣鍵盤的算(suàn)法一樣）

-----------------------------------------------------------------------

#include

#include

//獨立鍵盤.無按鍵動作(zuò)時(shí)其返回值num_key=0,否則返回按鍵号num_key

extern unsigned char keyboard_self()

{

        unsigned char num_key=0;//按鍵号

        unsigned char temp=0;//用于讀取P2線上(shàng)按鍵值

        static unsigned char temp_code=0;//保存按鍵值

        static unsigned char num_check=0;//低(dī)電(diàn)平有(yǒu)效次數(shù)

        static unsigned char key_flag=0;//按鍵有(yǒu)效标識

        temp=P2&0xF0;//讀取P2線數(shù)據

        if(temp!=0xF0)//低(dī)電(diàn)平判斷

        {

                num_check++;

                if(num_check==10)//連續10次(10ms)低(dī)電(diàn)平有(yǒu)效,則認為(wèi)按鍵有(yǒu)效

                {

                        key_flag=1;//使能按鍵有(yǒu)效标識

                        temp_code=temp;//保存按鍵值

                }

        }

        else//松手時(shí)判斷

        {

                num_check=0;

                if(key_flag==1)//按鍵有(yǒu)效

                {

                        key_flag=0;

                        switch(temp_code)//讀取按鍵号

                        {

                                case 0xE0: num_key=1;

                                           break;

                                case 0xD0: num_key=2;

                                           break;

                                case 0xB0: num_key=3;

                                           break;

                                case 0x70: num_key=4;

                                           break;

                        }

                }

        }

        return(num_key);

}

現在是矩陣鍵盤的

-----------------------------------------------------------------------

#include

#include  

//矩陣鍵盤.無按鍵動作(zuò)時(shí)其返回值num_key=0,否則返回按鍵号num_key****檢測高(gāo)四位

extern unsigned char keyboard_matrix()

{

        unsigned char num_key=0;//按鍵号

        unsigned char temp=0;//讀取P2口線數(shù)據

        static unsigned char temp_code=0;//用于保存按鍵值

        static unsigned char temp_circle=0xFE;//保存P2線上(shàng)的循環掃描值

        static unsigned char num_check=0;//低(dī)電(diàn)平計(jì)數(shù)

        static unsigned char key_flag=0;//按鍵有(yǒu)效标識

        P2=temp_circle;//0xFX

        temp=P2;//讀取P2口線數(shù)據

        if(temp!=temp_circle)//有(yǒu)按鍵動作(zuò)

        {

                num_check++;//低(dī)電(diàn)平計(jì)數(shù)|逢低(dī)電(diàn)平加1

                if(num_check==10)//連續10次(10ms)低(dī)電(diàn)平有(yǒu)效

                {

                        key_flag=1;//按鍵有(yǒu)效标識置1

                        temp_code=temp;//保存按鍵值

                }

        }

        else//松手OR無按鍵動作(zuò),此時(shí)應該改變掃描線

        {

                num_check=0;

                if(key_flag==1)//按鍵有(yǒu)效判斷

                {

                        key_flag=0;

                        switch(temp_code)//讀取按鍵号

                        {

                                //P2^0線

                                case 0xEE: num_key=1;

                                           break;

                                case 0xDE: num_key=2;

                                           break;

                                case 0xBE: num_key=3;

                                           break;

                                case 0x7E: num_key=4;

                                           break;

                                //P2^1線

                                case 0xED: num_key=5;

                                           break;

                                case 0xDD: num_key=6;

                                           break;

                                case 0xBD: num_key=7;

                                           break;

                                case 0x7D: num_key=8;

                                           break;

                                //P2^2線

                                case 0xEB: num_key=9;

                                           break;

                                case 0xDB: num_key=10;

                                           break;

                                case 0xBB: num_key=11;

                                           break;

                                case 0x7B: num_key=12;

                                           break;

                                //P2^3線

                                case 0xE7: num_key=13;

                                           break;

                                case 0xD7: num_key=14;

                                           break;

                                case 0xB7: num_key=15;

                                           break;

                                case 0x77: num_key=16;

                                           break;

                        }

                }

                temp_circle=_crol_(temp_circle,1);//改變掃描線

                if(temp_circle==0xEF)

                {

                        temp_circle=0xFE;

                }

        }

        return(num_key);//返回按鍵号

}

/*************************************************************************

未按鍵時(shí),掃描線一直變化。

長按鍵時(shí),掃描線不變化,使得(de)該行(xíng)按鍵變成了獨立按鍵,這樣的掃描效率極高(gāo)。

如當按下P2.0線上(shàng)的某個(gè)鍵時(shí),程序将掃描到這個(gè)鍵,而後掃描線不變化,

當鍵盤程序連續10次進入時(shí)檢測到10次按鍵有(yǒu)效,直到松手後掃描線才變化