key_t1.c

简单的键盘扫描程序。采用中断机制。加了个倒计时功能。

#include<at89x51.h>

unsigned int KEY_ID = 0;


void delay_ms(unsigned int count)
{
	int i,j;
	for(i= 0; i<=count; i++)
	{
		for(j=0;j<=120;j++)
		{;}
	}
}

void Key_Init(void)
{
	TMOD = 0x10;
	TH1 = 0x20;
	TL1 = 0x40;
	ET1 = 1;
	EA = 1;
	TR1 = 1;
}

void KEY_GET(void) interrupt 3 using 2
{
	ET1 = 0;
	P2_1 = 0;
	delay_ms(10);
	if(P2_4 == 0) KEY_ID = 5;
	if(P2_5 == 0) KEY_ID = 6;
	if(P2_6 == 0) KEY_ID = 7;
	if(P2_7 == 0) KEY_ID = 8;
	P2_1 = 1;

	P2_0 = 0;
	delay_ms(10);
	if(P2_4 == 0) KEY_ID = 1;
	if(P2_5 == 0) KEY_ID = 2;
	if(P2_6 == 0) KEY_ID = 3;
	if(P2_7 == 0) KEY_ID = 4; 
	P2_0 = 1;

	P2_2 = 0;
	delay_ms(10);
	if(P2_4 == 0) KEY_ID = 9;
	if(P2_5 == 0) KEY_ID = 10;
	if(P2_6 == 0) KEY_ID = 11;
	if(P2_7 == 0) KEY_ID = 12; 
	P2_2 = 1;

	P2_3 = 0;
	delay_ms(10);
	if(P2_4 == 0) KEY_ID = 13;
	if(P2_5 == 0) KEY_ID = 14;
	if(P2_6 == 0) KEY_ID = 15;
	if(P2_7 == 0) KEY_ID = 16; 
	P2_3 = 1;





	P0 = (KEY_ID / 10) * 16 + KEY_ID %10;
	delay_ms(50);

	TH1 = 0x20;
	TL1 = 0x40;
	ET1 = 1;
}

main()
{
	Key_Init();
 	while(1)
	{

	}

	
}