2021年11月24日 | C51键盘检测相关问题总结

附注：

原理图各接口连接关系可参考代码中的端口定义；

P0口数据锁存器为两片74HC573芯片；

1.对独立键盘的检测

/*--------------------------

功能：用数码管实现60s计时器

上电时，数码管显示00

key4控制开始/暂停计时

暂停状态下，key1进行加1操作

key2进行减1操作

key3进行清零操作

---------------------------

Author: Zhang Kaizhou

Date: 2019-5-19 19:14:20

--------------------------*/

#include

#define uchar unsigned char

#define uint unsigned int

sbit key1 = P3^4;

sbit key2 = P3^5;

sbit key3 = P3^6;

sbit key4 = P3^7;

sbit wei_address = P2^7;

sbit duan_address = P2^6;

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

  0x66, 0x6d, 0x7d, 0x07,

      0x7f, 0x6f, 0x77, 0x7c,

      0x39, 0x5e, 0x79, 0x71}; // 定义一个无符号字符型数组table[]，存放在单片机内部的ROM或Flash中

uchar n1 = 0, n2 = 0;

void init();

void display(uchar num);

void keyScan();

void delay(uchar xms);

void main()

{

init();

while(1)

{

keyScan();

display(n1);

}

}

/*初始化函数*/

void init()

{

TMOD = 0x01; // 定时器0，方式1

TH0 = (65536 - 45872) / 256; // 定时50ms

TL0 = (65536 - 45872) % 256;

EA = 1; // 开全局中断

ET0 = 1; // 开定时器0溢出中断

}

/*定时器0中断服务程序*/

void T0_interrupt() interrupt 1

{

TH0 = (65536 - 45872) / 256; // 定时器0重装初值

TL0 = (65536 - 45872) % 256;

n2++;

if(n2 == 20) // 定时到1s

{

n2 = 0;

n1++;

if(n1 == 60)

{

n1 = 0;

}

}

}

/*数码管显示函数*/

void display(uchar num)

{

uchar shi, ge;

shi = num / 10;

ge = num % 10;

duan_address = 1; // 在数码管上显示十位的数字

P0 = table[shi];

duan_address = 0;

P0 = 0xff;

wei_address = 1;

P0 = 0xfe;

wei_address = 0;

delay(5);

duan_address = 1; // 在数码管上显示个位的数字

P0 = table[ge];

duan_address = 0;

P0 = 0xff;

wei_address = 1;

P0 = 0xfd;

wei_address = 0;

delay(5);

}

/*键盘扫描函数*/

void keyScan()

{

if(!key1) // key1按下，加1

{

delay(10);

if(!key1) 

{

n1++;

if(n1 == 60)

{

n1 = 0;

}

while(!key1);

}

}

if(!key2) // key2按下，减1

{

delay(10);

if(!key2) 

{

if(!n1)

{

n1 = 60;

}

n1--;

while(!key2);

}

}

if(!key3) // key4按下，暂停或开始定时器0

{

delay(10);

if(!key3) 

{

n1 = 0;

while(!key3);

}

}

if(!key4)

{

delay(10);

if(!key4)

{

while(!key4);

TR0 = ~TR0;

}

}

}

/*延时函数*/

void delay(uchar xms)

{

uchar i, j;

for(i = 0; i < xms; i++)

for(j = 0; j < 110; j++);

}

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2.对矩阵键盘进行扫描

/*------------------------

功能：扫描4x4矩阵键盘

Author: Zhang Kaizhou

Date: 2019-5-21 21:37:31

-------------------------*/

#include

#define uchar unsigned char

sbit wei_address = P2^7;

sbit duan_address = P2^6;

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

  0x66, 0x6d, 0x7d, 0x07,

        0x7f, 0x6f, 0x77, 0x7c,

  0x39, 0x5e, 0x79, 0x71}; // 定义一个无符号字符型数组table[]，存放在单片机内部的ROM或Flash中

uchar buffer, key;

void init_digitron();

void array_scan_oneline(uchar address);

void array_scan();

void display(uchar key);

void delay(uchar xms);

void main()

{

init_digitron(); // 初始化数码管

while(1) // 循环逐行扫描按键是否按下

{

array_scan();

}

}

/*数码管初始化函数*/

void init_digitron()

{

P0 = 0; // 关闭所有数码管

duan_address = 1;

duan_address = 0;

P0 = 0x00; // 选中所有数码管

wei_address = 1;

wei_address = 0;

}

/*矩阵键盘扫描函数*/

void array_scan()

{

array_scan_oneline(0xfe);

array_scan_oneline(0xfd);

array_scan_oneline(0xfb);

array_scan_oneline(0xf7);

}

/*矩阵键盘扫描一行的函数*/

void array_scan_oneline(uchar address)

{

P3 = address;

buffer = P3;

buffer = buffer & 0xf0;

if(buffer != 0xf0) // 有键按下

{

delay(10); // 消抖

buffer = P3;

buffer = buffer & 0xf0;

if(buffer != 0xf0)

{

buffer = P3;

switch(buffer)

{

case 0xee: key = 0; break;

case 0xde: key = 1; break;

case 0xbe: key = 2; break;

case 0x7e: key = 3; break;

case 0xed: key = 4; break;

case 0xdd: key = 5; break;

case 0xbd: key = 6; break;

case 0x7d: key = 7; break;

case 0xeb: key = 8; break;

case 0xdb: key = 9; break;

case 0xbb: key = 10; break;

case 0x7b: key = 11; break;

case 0xe7: key = 12; break;

case 0xd7: key = 13; break;

case 0xb7: key = 14; break;

case 0x77: key = 15; break;

}

while(buffer != 0xf0) // 等待按键释放

{

buffer = P3;

buffer = buffer & 0xf0;

}

display(key);

}

}

}

/*延时函数*/

void delay(uchar xms)

{

uchar i, j;

for(i = 0; i < xms; i++)

for(j = 0; j < 110; j++);

}

/*数码管显示函数*/

void display(uchar key)

{

P0 = table[key];

duan_address = 1;

duan_address = 0;

}