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給你一個4*4矩陣鍵盤例程，有詳細注釋。
#include <AT89X52.H>
#define uint unsigned int //宏定義無符號整型數(shù)據(jù)
#define uchar unsigned char //宏定義無符號字符型數(shù)據(jù)
uchar key=0; //定義鍵值變量
void keyscan() //按鍵掃描程序
{
static bit sign=0; //按鍵有效標志
static uchar count=0; //消抖計數(shù)變量
uchar num=0;
P3=0xf0; //賦值P3 1111 0000
if((P3!=0xf0)&&(sign==0)) //檢測按鍵如果為0
{
count++; //消抖計數(shù)
if(count>=100) //100次檢測按鍵如果為0
{
count=100; //防止溢出
sign=1; //按鍵有效標志置1
num=P3; //保存P3值xxxx 0000，x為0或1
num=num|0x0f; //保存num按位或0x0f值xxxx 1111
P3=num; //賦值P3 xxxx 1111
num=P3; //保存P3值xxxx xxxx
switch(num)
{
case 0xee: key= 1; break;
case 0xde: key= 2; break;
case 0xbe: key= 3; break;
case 0x7e: key= 4; break;
case 0xed: key= 5; break;
case 0xdd: key= 6; break;
case 0xbd: key= 7; break;
case 0x7d: key= 8; break;
case 0xeb: key= 9; break;
case 0xdb: key=10; break;
case 0xbb: key=11; break;
case 0x7b: key=12; break;
case 0xe7: key=13; break;
case 0xd7: key=14; break;
case 0xb7: key=15; break;
case 0x77: key=16; break;
}
}
}
else
{
sign=0; //按鍵有效標志清0
count=0; //消抖計數(shù)清0
}
}
void main() //主函數(shù)
{
while(1)
{
keyscan(); //按鍵掃描程序
P1=~key; //LED顯示鍵碼1~16，低電平亮
}
} |
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