【51】 4x4按键 code

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最新推荐文章于 2024-08-13 10:30:50 发布

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分类专栏： 51 code

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#ifndef _KEYBOARD_H_
#define _KEYBOARD_H_

#include <8052.h>
#include "types.h"

#define keydata P1
void delay(INT16U time)
{
	while (--time);
}

INT8U Key_Scan(void)
{
	INT8U	i,key;
	INT8U	k = 255;
	
	keydata = 0xF0;
	if (keydata != 0xF0)
	{
		keydata = 0xFE;
		for (i = 0; i < 4; i++)
		{
			key = keydata & 0xf0;
			switch (key)
			{
				case 0xe0 :	k = i;		break;
				case 0xd0 : k = i + 4;	break;
				case 0xb0 :	k = i + 8;	break;
				case 0x70 : k = i + 12;	break;
				default   :	;			break;
			}
			keydata = (keydata << 1);
			if (k != 255)	break;
		}
		keydata = 0xF0;
		while (keydata != 0xF0);
		return (k);
	}
	else	return 'E';
}

#endif