鍵盤的應(yīng)用和分類：

鍵盤分為編碼鍵盤和非編碼鍵盤，鍵盤上閉合鍵的識(shí)別是由專門的硬件編碼器實(shí)現(xiàn)，并產(chǎn)生鍵編碼號(hào)或者是鍵值的成為編碼鍵盤，如計(jì)算機(jī)的鍵盤

靠軟件編程來識(shí)別的稱為非編碼鍵盤；

在單片機(jī)組成的各種系統(tǒng)中，用的最多的是非編碼鍵盤，也有用到編碼鍵盤的

非編碼鍵盤又有獨(dú)立鍵盤和矩陣鍵盤。

要先像鍵盤里面先寫1；在讀取操作

示例代碼：

#include

#define uint unsigned int

#define uchar unsigned char

sbit ld1 = P1^0;

sbit key1 = P3^4;

sbit dula = P2^6;

sbit wela = P2^7;

uchar num;

uchar code table[]={0x3f,0x06,0x5b,0x4f,

0x66,0x6d,0x7d,0x07,

0x7f,0x6f,0x77,0x7c,

0x39,0x5e,0x79,0x71};

void display(num);

main()

{

P3 = 0xff;

while(1)

{

display(num);

if(key1==0)

{

ld1 = 0;

num++;

if(num==10)

num = 0;

while(key1!=1);//松手檢測(cè)

}

else

ld1 = 1;

}

}

void display(num)

{

wela = 1;

P0 = 0xfe;

wela = 0;

P0 = 0x0;

dula = 1;

P0 = table[num];

dula = 0;

dula = 1;//關(guān)燈操作

P0 = 0x0;

dula = 0;

}

View Code

這個(gè)程序看上去無懈可擊，但是在實(shí)際過程中，有一個(gè)相當(dāng)大打bug，那就是，你按住鍵盤的時(shí)候，數(shù)碼管不顯示數(shù)字，這不是很坑爹，所以，位選信號(hào)是開始就要打開的正確的代碼是

#include

#define uint unsigned int

#define uchar unsigned char

sbit ld1 = P1^0;

sbit key1 = P3^4;

sbit dula = P2^6;

sbit wela = P2^7;

uchar num;

uchar code table[]={0x3f,0x06,0x5b,0x4f,

0x66,0x6d,0x7d,0x07,

0x7f,0x6f,0x77,0x7c,

0x39,0x5e,0x79,0x71};

void display(num);

main()

{

P3 = 0xff;

wela = 1;

P0 = 0xfe;//打開位選線

wela = 0;

while(1)

{

if(key1==0)

{

ld1 = 0;

num++;

if(num==10)

num = 0;

while(key1!=1);//松手檢測(cè)

}

else

ld1 = 1;

dula = 1;

P0 = table[num];//在循環(huán)中不斷送入段選

dula = 0;

}

}

去抖：由于按鍵接觸的時(shí)候會(huì)出現(xiàn)抖動(dòng)，所以，要進(jìn)行去抖操作

去抖有硬件消抖和軟件消抖

硬件消抖要用專門的硬件消抖電路，導(dǎo)致外部電路復(fù)雜，在單片機(jī)中用不著

軟件消抖，一般是延時(shí)5毫秒檢測(cè)

#include

#define uint unsigned int

#define uchar unsigned char

sbit ld1 = P1^0;

sbit key1 = P3^4;

sbit dula = P2^6;

sbit wela = P2^7;

uchar num;

uchar code table[]={0x3f,0x06,0x5b,0x4f,

0x66,0x6d,0x7d,0x07,

0x7f,0x6f,0x77,0x7c,

0x39,0x5e,0x79,0x71};

void delay(uint x);

main()

{

P3 = 0xff;

wela = 1;

P0 = 0xfe;//打開位選線

wela = 0;

while(1)

{

if(key1==0)

{

delay(10);//延時(shí)十毫秒

if(key1 == 0)//確實(shí)按下去了

{

ld1 = 0;

num++;

if(num==10)

num = 0;

while(key1!=1);//松手檢測(cè)

delay(10); //檢測(cè)是否松手

while(!key1);

}

}

else

ld1 = 1;

dula = 1;

P0 = table[num];//在循環(huán)中不斷送入段選

dula = 0;

}

}

void delay(uint x)

{

uint y,z;

for(y=x;y>0;y--)

for(z=110;z>0;z--);

}

矩陣鍵盤：無論是矩陣鍵盤還是獨(dú)立鍵盤，單片機(jī)檢測(cè)其是否被按下去的依據(jù)都是一樣的，也就是檢測(cè)該鍵盤對(duì)應(yīng)的I/O口是否為低電平，獨(dú)立鍵盤有一段固定是低電平，單片機(jī)寫程序時(shí)檢測(cè)比較方便，電路時(shí)矩陣鍵盤的兩端都與單片機(jī)deI/O口相連，因此在檢測(cè)時(shí)，先送入一列為低電平，其余的全部為高電平，此時(shí)我們確定了列數(shù)，然后立即輪流檢測(cè)一次各行是否有低電平，檢測(cè)到某一行為低電平（這是我們有確定了行數(shù)），著我們便可確定是哪一行哪一列的按鍵被按下去。

示例代碼：

#include

sbit wela =P2^6;

sbit dula = P2^7;

#define uchar unsigned char

#define uint unsigned int

void delay(uint z);

uchar num,num1,temp;

uchar keyscan();

uchar code table[]={0x3f,0x06,0x5b,0x4f,

0x66,0x6d,0x7d,0x07,

0x7f,0x6f,0x77,0x7c,

0x39,0x5e,0x79,0x71,0x0};

main()

{

wela = 1;

P0 = 0x0;

wela = 0;

while(1)

{

num1 = keyscan();

dula =1;

P0 = table[num1];

dula = 0;

}

}

void delay(uint z)

{

uint x,y;

for(x=z;x>0;x--)

for(y=110;y>0;y--);

}

uchar keyscan()

{

P3 = 0xfe;//1111 1110

temp = P3;

temp = temp&0xf0;//11110000

while(temp!=0xf0)//如果有鍵摁下

{

delay(5);//再次檢測(cè)P3口

temp = P3;

temp = temp&0xf0;

while(temp!=0xf0)

{

temp = P3;

switch(temp)

{

case 0x7e:num = 1;

break;

case 0xbe:num = 2;

break;

case 0xde:num = 3;

break;

case 0xee:num = 4;

break;

}

while(temp!=0xf0)//松手檢測(cè)

{

temp = P3;

temp = temp&0xf0;

}

}

}

P3 = 0xfd;//1111 1101

temp = P3;

temp = temp&0xf0;//11110000

while(temp!=0xf0)//如果有鍵摁下