用74HC165读8个按键状态（转）

源：用74HC165读8个按键状态
//--------------------------------------------------------------------------
//来源:            http://hi.baidu.com/mculove/home
//程序名称:        用74HC165读8个按键状态
//晶振:            11.0592MHz;
//MCU型号:        STC89C52RC;
//电路板型号:    EBV-MV(51实验板);
//--------------------------------------------------------------------------




//--------------------------------------------------------------------------
//硬件连接:
//EBVn-[VCC]    ->    MVn-[--VCC--]
//EBVn-[GND]    ->    MVn-[//GND//]
//MVn-{EX3}-[Y0]    ->    MVn-{EX2}-[L1]
//MVn-{EX3}-[Y1]    ->    MVn-{EX2}-[L2]
//MVn-{EX3}-[Y2]    ->    MVn-{EX2}-[L3]
//MVn-{EX3}-[Y3]    ->    MVn-{EX2}-[L4]
//MVn-{EX3}-[Y4]    ->    MVn-{EX2}-[L5]
//MVn-{EX3}-[Y5]    ->    MVn-{EX2}-[L6]
//MVn-{EX3}-[Y6]    ->    MVn-{EX2}-[L7]
//MVn-{EX3}-[Y7]    ->    MVn-{EX2}-[L8]
//                     ->    MVn-{EX2}-(VCC)
//                      ->    MVn-{EX3}-(VCC)

//EBVn-[P10]        ->    MVn-{EX3}-[A]
//EBVn-[P11]        ->    MVn-{EX3}-[B]
//EBVn-[P12]        ->    MVn-{EX3}-[C]
//EBVn-[P13]        ->    MVn-{EX3}-[G1]
//--------------------------------------------------------------------------




//--------------------------------------------------------------------------
//实验结果:
//控制74HC138的[A,B,C,G1]端口,使[Y0,Y1..Y7]输出预期的值,LED实现了流水灯显示
//--------------------------------------------------------------------------



//------------------------------------------------------
//头文件;
#include <AT89X52.H>

#define HC165_nPL   P3_5
#define HC165_CK    P3_6
#define HC165_OUT    P3_7

//------------------------------------------------------
void delay(void)
{
    unsigned char i,j;
    for(i = 250;i > 0;i--)
    for(j = 200;j > 0;j--);
}

unsigned char HC165(void)
{
    unsigned char i;
    unsigned char Temp;
    HC165_CK = 1;
    HC165_nPL = 0;        //HC165读按键
    HC165_nPL = 1;        //暂停HC165读按键
    Temp = 0;
    if(HC165_OUT == 1) Temp |= 0x01;
    for(i = 0;i < 7;i++)
    {    
        HC165_CK = 0;  
        HC165_CK = 1;  
        Temp <<= 1;
        if(HC165_OUT == 1) 
        {
            Temp |= 0x01;
        }
    }
    HC165_CK = 0;
    return(Temp);
}
 


//------------------------------------------------------
//程序入口;
void main(void)
{
    while(1)
    {
      P1 = HC165();
      delay();
    }
}