PIC单片机一个实用的按键处理程序

#include
__CONFIG(0X034);
#define KEY RC5
#define LEDRC2
int b;
void key(unsigned *p)
{
static bit valid=0;
static bit finish=0;
if(valid==0)
{
if(KEY==0)
{
if(finish==0)
{
finish=1;

RC0=1;//蜂鸣器接这里
b=50;
while(b--);
RC0=0;

if(*p>251)
{
*p=0x01;
}
else
{
*p+=50;

}
}
}
else
{
valid=0;
finish=0;
}
}
else
{
if(KEY==0)valid=1;
}
}
void tiaoguang(unsigned PWM)
{
unsigned char PwmH;
unsigned char PwmL;
unsigned char i;
for(i=0;i<20;i++)
{
PwmH=PWM;
PwmL=255-PWM;

LED=1;
while(PwmH--);
LED=0;
while(PwmL--);

}

}
void main()
{
unsigned char PWM=0;
RC2=0;
TRISC=0b00100000;
while(1)
{
key(&PWM);
tiaoguang(PWM);

}

}

程序思路：设定PWM变量，每按一次，PWM增加50个单位，加到到250，归零。