用51单片机的矩阵键盘输入三位数
时间: 2024-06-13 15:07:35 浏览: 70
要使用51单片机的矩阵键盘输入三位数,可以按照以下步骤进行:
1. 首先需要连接好矩阵键盘和51单片机,确保电路连接正确。
2. 在程序中定义矩阵键盘的行列数,以及对应的端口号和引脚号。例如:
```
#define ROWS 4
#define COLS 4
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;
```
3. 编写扫描矩阵键盘的函数,该函数需要循环扫描矩阵键盘的每一个按键,当检测到按键按下时,将对应的数字存储到一个数组中。例如:
```
void scan_keypad(unsigned char *key)
{
unsigned char row, col;
unsigned char keymap[ROWS][COLS] = {
{'1', '2', '3', 'A'},
{'4', '5', '6', 'B'},
{'7', '8', '9', 'C'},
{'*', '0', '#', 'D'}
};
for (col = 0; col < COLS; col++)
{
switch (col)
{
case 0:
COL1 = 0; COL2 = 1; COL3 = 1; COL4 = 1; break;
case 1:
COL1 = 1; COL2 = 0; COL3 = 1; COL4 = 1; break;
case 2:
COL1 = 1; COL2 = 1; COL3 = 0; COL4 = 1; break;
case 3:
COL1 = 1; COL2 = 1; COL3 = 1; COL4 = 0; break;
}
for (row = 0; row < ROWS; row++)
{
if (ROW1 == 0) { *key = keymap[row][col]; while(!ROW1); return; }
if (ROW2 == 0) { *key = keymap[row][col]; while(!ROW2); return; }
if (ROW3 == 0) { *key = keymap[row][col]; while(!ROW3); return; }
if (ROW4 == 0) { *key = keymap[row][col]; while(!ROW4); return; }
}
}
}
```
4. 在主函数中调用扫描矩阵键盘的函数,将输入的三位数存储到一个数组中。例如:
```
void main()
{
unsigned char key[3];
unsigned char i = 0;
while (i < 3)
{
scan_keypad(&key[i]);
if (key[i] >= '0' && key[i] <= '9')
{
i++;
}
}
// 将输入的三位数转换为整数
unsigned int num = (key[0] - '0') * 100 + (key[1] - '0') * 10 + (key[2] - '0');
}
```
这样就可以通过矩阵键盘输入三位数了。
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