AVR 矩阵键盘程序源代码(原创)

使用方法:放入工程,调用GetKeyValue,没按键时返回KEY_NULL,有按键时为按键字符,字符见文章最下面

/********** AVR 矩阵键盘扫描程序 *********
* 版本.........: 1.0
* 作者.........: 陈利栋
* 目标.........: AVR
* 文件名.......: Keyboard.h
* 编译器.......: AVR GCC 20100110
* 开发环境.....: AVR Studio V4.18
* 创建时间.....: 2010.09.12
* 最后修改.....: 2010.09.12
*****************************************/
#ifndef __KEYBOARD_H__
#define __KEYBOARD_H__

#include <avr/io.h>
#include <util/delay.h>

#define KEYBOARD_PORT        PORTA
#define KEYBOARD_DDR         DDRA
#define KEYBOARD_PIN         PINA

#define KEY_NULL             0xff
#define KEY_READY_COUNT      1000  //此值在不同环境下应适当调整(1 - 65535),值越小,灵敏度越高

extern unsigned char GetKeyValue(void);

#endif /* __KEYBOARD_H__ */

 

 

/********** AVR 矩阵键盘扫描程序 *********
* 版本.........: 1.0
* 作者.........: 陈利栋
* 目标.........: AVR
* 文件名.......: Keyboard.c
* 编译器.......: AVR GCC 20100110
* 开发环境.....: AVR Studio V4.18
* 创建时间.....: 2010.09.12
* 最后修改.....: 2010.09.12
*****************************************/
#include "Keyboard.h"

unsigned char _key_last = KEY_NULL;
unsigned int  _key_count = 0;

unsigned char KeyScan(void)
{
    unsigned char temp = 0;

    KEYBOARD_DDR = 0x0f;
    KEYBOARD_PORT = 0xf0;
    _delay_us(1);
    temp = KEYBOARD_PIN;

    KEYBOARD_DDR = 0xf0;
    KEYBOARD_PORT = 0x0f;
    _delay_us(1);
    temp |= KEYBOARD_PIN;

    if (temp != _key_last)
    {
        _key_count++;
        if (_key_count >= KEY_READY_COUNT)
        {
            _key_last = temp;
            _key_count = 0;
            return _key_last;
        }
    }
    else
    {
        _key_count = 0;
    }

    return KEY_NULL;
}

unsigned char GetKeyValue(void)
{
    switch (KeyScan())
    {    
        case KEY_NULL: return KEY_NULL;
        case 0x77: return '1';
        case 0x7B: return '2';
        case 0x7D: return '3';
        case 0x7E: return 'A';
        case 0xB7: return '4';
        case 0xBB: return '5';
        case 0xBD: return '6';
        case 0xBE: return 'B';
        case 0xD7: return '7';
        case 0xDB: return '8';
        case 0xDD: return '9';
        case 0xDE: return 'C';
        case 0xE7: return '*';
        case 0xEB: return '0';
        case 0xED: return '#';
        case 0xEE: return 'D';
        default  : return KEY_NULL;
    }
}