#循循渐进学51单片机#函数进阶与按键#not.7

1、掌握单片机最小系统三要素电路设计规则。

1)

2)

3)

2、掌握函数间相互调用的方法和规则。

函数的形式参数和实际参数

实参:在调用一个有参数的函数时，函数名后边括号中的参数。

形参:在被调用的函数进行定义时，括号内的参数叫做形式参数。

1、函数定义中指定的形参，在未发生调用时不占用内存，函数调用时分配内存单元，调用结束释放内存。

2，或者复杂的表达式，但是要求必须有确定的值，在调用时传递给形参。c=add(1,a+b);

3、参必须制定数据类型，和变量定义一样。

4参和实参的数据类型应该相同或者赋值兼容。

5、主调函数在调用函数之前，应对被调函数做原型声明。

6、实参向形参的数据传递是单向传递，不能有形参再回传给实参。 

3、会独立按键和矩阵按键的电路设计方法和软件编程思路。

1)

2)

3）

4）按键消抖方法，遍历八个字节，当八个字节在连续时间字节相同，则判定按钮按下

5）按钮按下与否的判断，就是跟按钮前一刻的值判断，当前值与前一刻的值不同，则按钮按下。

4一按实现一个数码管数字从F~0递减的变化程序。

#include 
sbit addr0 = P1^0;
sbit addr1 = P1^1;
sbit addr2 = P1^2;
sbit addr3 = P1^3;
sbit ENLED = P1^4;

sbit KeyIn1 = P2^4;
sbit KeyIn2 = P2^5;
sbit KeyIn3 = P2^6;
sbit KeyIn4 = P2^7;

sbit KeyOut1 = P2^3;
sbit KeyOut2 = P2^2;
sbit KeyOut3 = P2^1;
sbit KeyOut4 = P2^0;
unsigned char code LedChar[] = {  //ÊýÂë¹ÜÏÔʾ×Ö·ûת»»±í
    0xC0, 0xF9, 0xA4, 0xB0, 0x99, 0x92, 0x82, 0xF8,
    0x80, 0x90, 0x88, 0x83, 0xC6, 0xA1, 0x86, 0x8E
};

 bit i = 1,Key = 1;
unsigned int cnt = 0;
void main()
{
	EA = 1;
	KeyOut4 = 0;
	ENLED = 0;
	addr3 = 1;
	TMOD = 0x01;
	TH0 = 0xF8;
	TL0 =0xcb;
	addr1 = 0;
	addr2 = 0;
	addr0 = 0;
	ET0 = 1;
	TR0 = 1;
P0 = LedChar[cnt];
  while(1)
{
 if(Key != i)
 {
	if(i == 0)
	{
	P0 = LedChar[cnt];
	cnt++;
		if(cnt >= 15)
		{
		cnt = 0;
		}
	}
	i = Key;
 }
}	
}

void InterruptTimer0() interrupt 1
{
  static unsigned int arr = 0xff;
	TH0 = 0xF8;
	TL0 =0xcb;
	arr = (arr << 1) |  KeyIn2;
	if(arr == 0xff)
	{
	Key = 1;
	}
	else if(arr == 0x00)
	{
	Key = 0;
	}
	else {}
}	

5、用矩阵按键做一个简易减法计算器。

#include 
sbit addr0 = P1^0;
sbit addr1 = P1^1;
sbit addr2 = P1^2;
sbit addr3 = P1^3;
sbit ENLED = P1^4;

sbit KeyIn1 = P2^4;
sbit KeyIn2 = P2^5;
sbit KeyIn3 = P2^6;
sbit KeyIn4 = P2^7;

sbit KeyOut1 = P2^3;
sbit KeyOut2 = P2^2;
sbit KeyOut3 = P2^1;
sbit KeyOut4 = P2^0;
unsigned char code LedChar[] = { 
    0xC0, 0xF9, 0xA4, 0xB0, 0x99, 0x92, 0x82, 0xF8,
    0x80, 0x90, 0x88, 0x83, 0xC6, 0xA1, 0x86, 0x8E
};
unsigned char LedBuff[6] = {  
    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF
};
unsigned char code KeyCodeMap[4][4] = {
    { 0x31, 0x32, 0x33, 0x26 },
    { 0x34, 0x35, 0x36, 0x25 }, 
    { 0x37, 0x38, 0x39, 0x28 }, 
    { 0x30, 0x1B, 0x0D, 0x27 }  
};
unsigned char KeySta[4][4] = { 
    {1, 1, 1, 1},  {1, 1, 1, 1},  {1, 1, 1, 1},  {1, 1, 1, 1}
};

void KeyDriver();
void main()
{
	EA = 1;       
    ENLED = 0;   
    addr3 = 1;
    TMOD = 0x01;  
    TH0  = 0xFC;  
    TL0  = 0x67;
    ET0  = 1;     
    TR0  = 1;     
    LedBuff[0] = LedChar[0];  
	
    while (1)
    {
        KeyDriver();   
    }
	
}


	

void ShowNumber(long num)
	{
	 signed char i;
    unsigned char sign;
    unsigned char buf[6];
    
    if (num < 0) 
    {
        sign = 1;
        num = -num;
    }
    else
    {
        sign = 0;
    }
    for (i=0; i<6; i++)   
    {
        buf[i] = num % 10;
        num = num / 10;
    }
    for (i=5; i>=1; i--) 
    {
        if (buf[i] == 0)
            LedBuff[i] = 0xFF;
        else
            break;
    }
    if (sign != 0)        
    {
        if (i < 5)        
        {
            LedBuff[i+1] = 0xBF;
        }
    }
    for ( ; i>=0; i--)  
    {
        LedBuff[i] = LedChar[buf[i]];
    }
	}
void KeyAction(unsigned char keycode)
{
    static char oprt = 0;    
    static long result = 0;  
    static long addend = 0;  
    
    if ((keycode>=0x30) && (keycode<=0x39)) 
    {
        addend = (addend*10)+(keycode-0x30); 
        ShowNumber(addend);  
    }
    else if (keycode == 0x26) 
    {
        oprt = 0;              
        result = addend;      
        addend = 0;            
        ShowNumber(addend);    
    }
    else if (keycode == 0x28) 
    {
        oprt = 1;              
        result = addend;
        addend = 0;           
        ShowNumber(addend);    
    }
    else if (keycode == 0x0D)  
    {
        if (oprt == 0)
        {
            result += addend;  
        }
        else
        {
            result -= addend;  
        }
        addend = 0;
        ShowNumber(result);    
    }
    else if (keycode == 0x1B)  
    {
        addend = 0;
        result = 0;
        ShowNumber(addend);  
    }
}
void KeyDriver()
{
    unsigned char i, j;
    static unsigned char backup[4][4] = {  
        {1, 1, 1, 1},  {1, 1, 1, 1},  {1, 1, 1, 1},  {1, 1, 1, 1}
    };
    
    for (i=0; i<4; i++)  
    {
        for (j=0; j<4; j++)
        {
            if (backup[i][j] != KeySta[i][j])  
            {
                if (backup[i][j] != 0)           
                {
                    KeyAction(KeyCodeMap[i][j]); 
                }
                backup[i][j] = KeySta[i][j];     
            }
        }
    }
}
	



	void KeyScan()
{
  static	unsigned char add = 0;
	 unsigned char j ;
  static unsigned char keybuf[4][4] = {  
        {0xFF, 0xFF, 0xFF, 0xFF},  {0xFF, 0xFF, 0xFF, 0xFF},
        {0xFF, 0xFF, 0xFF, 0xFF},  {0xFF, 0xFF, 0xFF, 0xFF}
    };
	    keybuf[add][0] = (keybuf[add][0] << 1) | KeyIn1;
			keybuf[add][1] = (keybuf[add][1] << 1) | KeyIn2;
			keybuf[add][2] = (keybuf[add][2] << 1) | KeyIn3;
			keybuf[add][3] = (keybuf[add][3] << 1) | KeyIn4;
		for(j = 0;j <4;j++)
		{
		if( (keybuf[add][j] & 0x0F) == 0x00 )
		{
		  KeySta[add][j] = 0;
		}
		else if((keybuf[add][j] & 0x0F) == 0x0f)
		{
			KeySta[add][j] = 1;
		}
		}
    add++;
		add = add & 0x03;
		switch(add)
		{
			case 0:KeyOut4 = 1;KeyOut1 = 0;break;
			case 1:KeyOut1 = 1;KeyOut2 = 0;break;
			case 2:KeyOut2 = 1;KeyOut3 = 0;break;
			case 3:KeyOut3 = 1;KeyOut4 = 0;break;
			default:break;
		}
}
void LedScan() 
{
 static unsigned char i = 0;
	P0 = 0xff;
	switch(i)
	{
		    case 0:addr2 = 0;addr1 = 0;addr0 = 0;i++;P0 = LedBuff[0];break;
				case 1:addr2 = 0;addr1 = 0;addr0 = 1;i++;P0 = LedBuff[1];break;
				case 2:addr2 = 0;addr1 = 1;addr0 = 0;i++;P0 = LedBuff[2];break;
				case 3:addr2 = 0;addr1 = 1;addr0 = 1;i++;P0 = LedBuff[3];break;
				case 4:addr2 = 1;addr1 = 0;addr0 = 0;i++;P0 = LedBuff[4];break;
				case 5:addr2 = 1;addr1 = 0;addr0 = 1;i=0;P0 = LedBuff[5];break;
		default:break;
	}
}	
void InterruptTimer0() interrupt 1
{
    TH0 = 0xFC;  
    TL0 = 0x67;
    LedScan();   
    KeyScan();  
}