下圖是鍵盤時(shí)序圖,上面是PS2發(fā)送時(shí)序,下面是PS2鍵盤接收時(shí)序.

下面的代碼是用PS2鍵盤控制LED顯示按鍵編碼.按住顯示的是通碼.放開顯示的是斷碼.但由于斷碼最后8位是通碼一樣(不包括多位通碼).所以顯示一般是一樣的.

單片機(jī)P3.3接PS2按口的5為時(shí)鐘CLK,P3.4接PS2接口的1為數(shù)據(jù)DATA,因?yàn)閱纹瑱C(jī)初始并口輸出為全1,所以數(shù)據(jù)線與時(shí)鐘線都為1,而PS2發(fā)數(shù)據(jù)時(shí),由鍵盤產(chǎn)生時(shí)鐘信號與數(shù)據(jù)信號,發(fā)完數(shù)據(jù)線信號與時(shí)鐘線信號都變?yōu)楦?

代碼如下:

#include

#include

#define ESC_CODE 0x76 //ESC鍵碼

sbit PS2_DATA = P3^4; //PS2數(shù)據(jù)線

sbit PS2_CLK = P3^3; //PS2時(shí)鐘線

sbit BEEP = P3^7; //蜂鳴器驅(qū)動(dòng)線

unsigned char TEMP;

unsigned char KeyCode; //鍵盤鍵值

unsigned char code TABLE_D[] = { //鍵值碼

0x1c,0x32,0x21,0x23,0x24,0x2b,0x34,0x33,0x43,0x3b,0x42,

0x4b,0x3a,0x31,0x44,0x4d,0x15,0x2d,0x1b,0x2c,0x3c,0x2a,0x1d,0x22,0x35,0x1a, //a-z

0x45,0x16,0x1e,0x26,0x25,0x2e,0x36,0x3d,0x3e,0x46, //0-9

0x0e,0x4e,0x55,0x5d,0x29,0x54,0x5b,0x4c,0x52,0x41,0x49,0x4a,0x71, //標(biāo)點(diǎn)符號

0x70,0x69,0x72,0x7a,0x6b,0x73,0x74,0x6c,0x75,0x7d, //右邊數(shù)字鍵0-9

0xff };

void delay(unsigned int x)

{

unsigned char i;

while(x--)

{

for (i=0; i<13; i++) ;

}

}

void beep()

{

unsigned char i;

for (i=0;i<100;i++)

{

delay(5);

BEEP=!BEEP; //BEEP取反

}

BEEP=1; //關(guān)閉蜂鳴器

}

unsigned char ReadPS2()

{

unsigned char i; //位數(shù)

while(PS2_CLK); //等待鍵盤把時(shí)鐘第一次拉低，表示

for(i=8; i!=0; i--) // 把起始位算入

{

while(!PS2_CLK); //等待一個(gè)有效的下跳沿，這兩條while是半個(gè)周期,主設(shè)備在下降沿讀數(shù)據(jù)

while( PS2_CLK);

KeyCode >>= 1; //數(shù)據(jù)低位在前

if(PS2_DATA == 1)

KeyCode |= 0x80; // 得到有效的數(shù)據(jù)位

}

for(i=2;i!=0;i--) //等待鍵盤發(fā)送效驗(yàn)位和終止位

{

while(!PS2_CLK);

while( PS2_CLK);

}

while(!PS2_CLK); //等待鍵盤把時(shí)鐘線拉高

TEMP = KeyCode;

TEMP = ~TEMP;

P2=TEMP; //顯示鍵碼

return(KeyCode); //返回按鍵值

}

void PS2KEY()

{

unsigned char y;

for(y=0 ;y<60 ;y++) //鍵值變換為順序碼

{

if(KeyCode==TABLE_D[y])

{

delay(1000);

beep() ; //查找有效，蜂鳴器響一聲

}

}

}

void main()

{

P2 = 0xff; //關(guān)閉所有LED

while(1)

{

ReadPS2();

if(KeyCode==ESC_CODE) //Esc鍵碼

{

P2 = 0xff; //關(guān)閉所有LED

}

PS2KEY();

}

}

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