key.c

在LPC2368上实现的FFT程序

#include <LPC23xx.H>
#include "key.h"
enum KEY_STATUS key_Status=KEY_WAIT;
//读取键盘值，没有键按下时 ，返回0x3f
unsigned char read_key()
{
    unsigned char key_value=0xff; 
    key_value=FIO0PIN2; 
	key_value>>=2;
    return key_value;
            
}
void key_Scan()
{
    unsigned char key=0;
    unsigned char key_backup=0;
    unsigned char flag=1;
    unsigned char j=0;
    unsigned char time_counter=5;
    unsigned int n=0;
    while(flag)
    {
        key=read_key();
        
        if(key!=0x1f)
        {
            j++; 
            key_backup=key;   
        }
        else
        {
            flag=0;
            if(j<=4)
            {
                return;
            }
            else
            {
                break;
            }
        }
        if(j==0xff)
        {
       	    j=6;
        }
        while(time_counter>=1)
        {
        	for(n=5000;n>1;n--);
	        time_counter--;
        }
        time_counter=10;
    }
    switch(key_backup)
    {
        case 0x1E:
            key_Status=KEY_HOLD;
            break;
        case 0x1D:
            key_Status=KEY_ENTER;
            break;
        case 0x1B:
            key_Status=KEY_RIGHT;
            break;
        case 0x17:
            key_Status=KEY_DOWN;
            break;
		case 0x0F:
            key_Status=KEY_RECALL;
            break;
		default:
			key_Status=KEY_WAIT;
			break;
    }
}