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硬件防抖电路图

#include "reg52.h"

#define GPIO_KEY P1
#define GPIO_DIG P0

typedef unsigned char u8;
typedef unsigned int u16;

sbit LSA = P2^2;
sbit LSB = P2^3;
sbit LSC = P2^4;

u8 code smgduan[]=
{
	0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x6f, 0x77, 0x7c, 0x39, 0x5e, 0x79, 0x71
};
u8 keyValue=0;

void delayus(u16 i)
{
	while(i--);
}
void keyDown()
{
	u8 a =0;
	GPIO_KEY = 0x0f;
	if (GPIO_KEY != 0x0f)
	{
		delayus(1000);
		
		if(GPIO_KEY != 0X0F)
		{
			GPIO_KEY = 0x0f;
			switch(GPIO_KEY)
			{
				case(0x07): keyValue=0;break;
				case(0x0b): keyValue=1;break;
				case(0x0d): keyValue=2;break;
				case(0x0e): keyValue=3;break;
			}
			GPIO_KEY=0xf0;
			switch(GPIO_KEY)
			{
				case(0x70): keyValue=keyValue;break;
				case(0xb0): keyValue=keyValue+4;break;
				case(0xd0): keyValue=keyValue+8;break;
				case(0xe0): keyValue=keyValue+12;break;
			}
			while(a<50 && GPIO_KEY!=0xf0)
			{
				delayus(1000);
			}

		}
	}
}
void main()
{
	LSA=0;
	LSB=0;
	LSC=0;
	while(1)
	{
		keyDown();
		GPIO_DIG=smgduan[keyValue];		
	}
}