COM3（j5）选择2 3引脚为独立按键选择 1 2引脚为矩阵按键

在按键中一方接地一方接芯片
当按键按下时芯片的一方会从高低平变成低电平
这时就可知判定按键是否按下

需注意按键按下时具有抖动
会影响实际效果
这时就需要消抖
按后延迟20毫秒
再进行程序操作
再进行按键判定
按键判定：while（所需判定按键）；
列： while(S7==0);

基本代码：

include<STC15F2K60S2.H>

sbit S7 = P3^0;//定义所需按键
sbit S6 = P3^1;
sbit S5 = P3^2;
sbit S4 = P3^3;

sbit L1 = P0^0;//定义所需LED
sbit L2 = P0^1;
sbit L3 = P0^2;
sbit L4 = P0^3;
sbit L5 = P0^4;
sbit L6 = P0^5;
void SelectHC573(unsigned char n)//锁存器选择
{
switch(n)
{
case 4:
P2 = (P2 & 0x1f) | 0x80;
break;
case 5:
P2 = (P2 & 0x1f) | 0xa0;
break;
case 6:
P2 = (P2 & 0x1f) | 0xc0;
break;
case 7:
P2 = (P2 & 0x1f) | 0xe0;
break;
}
}

void Delayk(unsigned char t)//二次延迟（将月份动态显示）
{
while(t--);
}
void ScanKeys_Alone()独立按键
{
if(S7== 0)
{
Delayk(100);//消抖延迟
if(S7== 0)
{
L1 = 0;
while(S7==0);//按键判定
L1 = 1;
}
}

if(S6== 0)
{
	Delayk(100);
	if(S6== 0)
	{
		L2 = 0;
		while(S6==0);
		L2 = 1;
			
	}
}

if(S5== 0)
{
	Delayk(100);
	if(S5== 0)
	{
		L3 = 0;
		while(S5==0);
		L3 = 1;

	}
}

if(S4== 0)
{
	Delayk(100);
	if(S4== 0)
	{
		L4 = 0;
		while(S4==0);
		L4 = 1;

	}
}

}

void f ()//初始化
{
SelectHC573(5);
P0=0x00;
SelectHC573(4);
P0=0xff;
}

void main ()
{
f ();
SelectHC573(4);

while(1)
{
	ScanKeys_Alone();
}

}

进阶代码：

include<STC15F2K60S2.H>

sbit S7 = P3^0;
sbit S6 = P3^1;
sbit S5 = P3^2;
sbit S4 = P3^3;

sbit L1 = P0^0;
sbit L2 = P0^1;
sbit L3 = P0^2;
sbit L4 = P0^3;
sbit L5 = P0^4;
sbit L6 = P0^5;
void SelectHC573(unsigned char n)
{
switch(n)
{
case 4:
P2 = (P2 & 0x1f) | 0x80;
break;
case 5:
P2 = (P2 & 0x1f) | 0xa0;
break;
case 6:
P2 = (P2 & 0x1f) | 0xc0;
break;
case 7:
P2 = (P2 & 0x1f) | 0xe0;
break;
}
}

void Delayk(unsigned char t)
{
while(t--);
}

unsigned char stat_k = 0;//定义变量（状态选定）
void ScanKeys_Alone()
{
if(S7== 0)//状态1 按下s7后改变s4，s5的亮灯方式位置
{
Delayk(100);
if(S7== 0)
{
if(stat_k == 0)
{
L1=0;
stat_k = 1;
}
else if (stat_k== 1)
{
L1= 1;
stat_k = 0;
}
while(S7==0);
}
}

if(S6== 0)//状态2 当按下s6后改变s4，s5的亮灯位置 
{
	Delayk(100);
	if(S6== 0)
	{
		if(stat_k ==0)
		{
			L2=0;
			stat_k =2;
		}
		else if(stat_k ==2)
		{
			L2 = 1;
			stat_k = 0;
    				
		}
		while(S6==0);
	}
}

if(S5== 0)
{
	Delayk(100);
	if(S5== 0)
	{
		if(stat_k ==1)
		{
			L3 = 0;
			while(S5 == 0);
			L3 = 1;
		}
		else if(stat_k ==2)
		{
			L5 = 0;
			while(S5 == 0);
			L5 = 1;
		}
			
			
	}
}

if(S4== 0)
{
	Delayk(100);
	if(S4== 0)
	{
		if(stat_k ==1)
		{
			L4 = 0;
			while(S4==0);
			L4 = 1;
		}	
		else if(stat_k ==2)
		{
			L6 = 0;
			while(S4==0);
			L6 = 1;
		}
	}
}

}

void f ()
{
SelectHC573(5);
P0=0x00;
SelectHC573(4);
P0=0xff;
}

void main ()
{
f ();
SelectHC573(4);