2X4矩阵按键扫描代码
时间: 2023-07-09 22:22:10 浏览: 47
好的,以下是一个基于51单片机的2x4矩阵按键扫描代码示例:
```c
#include <reg51.h>
#define uchar unsigned char
#define uint unsigned int
sbit ROW1 = P1^0;
sbit ROW2 = P1^1;
sbit ROW3 = P1^2;
sbit ROW4 = P1^3;
sbit COL1 = P1^4;
sbit COL2 = P1^5;
sbit COL3 = P1^6;
sbit COL4 = P1^7;
uchar code keyValue[4][4] = {{'1', '2', '3', 'A'},
{'4', '5', '6', 'B'},
{'7', '8', '9', 'C'},
{'*', '0', '#', 'D'}};
uchar keyCode = 0;
void delay(uint t)
{
while(t--);
}
uchar getKeyCode()
{
uchar row, col;
P1 |= 0xF0;
while(1)
{
ROW1 = 0;
if(!(P1 & 0x10))
{
row = 0;
break;
}
ROW2 = 0;
if(!(P1 & 0x20))
{
row = 1;
break;
}
ROW3 = 0;
if(!(P1 & 0x40))
{
row = 2;
break;
}
ROW4 = 0;
if(!(P1 & 0x80))
{
row = 3;
break;
}
return 0xFF;
}
P1 &= 0x0F;
while(1)
{
col = P1;
if(col == 0x0F)
continue;
else
break;
}
delay(1000); //消除抖动
col = P1;
P1 |= 0xF0;
if(col == 0xE0)
return keyValue[row][0];
else if(col == 0xD0)
return keyValue[row][1];
else if(col == 0xB0)
return keyValue[row][2];
else if(col == 0x70)
return keyValue[row][3];
else
return 0xFF;
}
void main()
{
P1 = 0xFF;
while(1)
{
keyCode = getKeyCode();
if(keyCode != 0xFF)
{
//处理按键
//...
}
}
}
```
该示例中使用了P1口的低四位作为列扫描线,高四位作为行扫描线,通过按键矩阵的连接方式,实现按键的检测和读取。在getKeyCode()函数中,先将P1口全部置高,然后逐行将行扫描线置低,检测列扫描线的状态,得到按键的行和列信息,最后根据按键矩阵的映射表,返回对应的按键值。为了消除按键的抖动,还在读取列扫描线的状态之后,延时一段时间再次读取,确保按键状态的稳定。