key.c

51单片机的键盘扫描程序,当有键盘输入是,将在LED上显示,且蜂鸣器将发出相应的响声.

//key.c
#include"general.h"
#include"sys12M.h"
sbit key = P1^0;
//initialize the key_board
void init_key(void)
{
	EAIO = 0xFF;
	DATA = 0x00;
}

//scan the key when there is a key-press
BYTE scan_key(void)
{
	BYTE i;
	delay(10);
	if(key) return 0;
	DATA = 0xFE;
	for(i=1,key=1;i<8;i++)
	{
		
		if(!key) break;
		DATA = _crol_(DATA,1);
	}
	delay(10);
	return DATA;
}
//read the key when there is a key-press
BYTE read_key(void)
{
	BYTE i;
	if(key) return 0;
	DATA = 0xFE;
	for(i=1,key=1;i<8;i++)
	{
		
		if(!key) break;
		DATA = _crol_(DATA,1);
	}
	delay(10);
	return i;
}