#include "Matrix_Key.h"
/*
 * 矩陣鍵盤通用程序(引腳輸入輸出方向不切換)
 */

//KEY_PINS 低4位為ROW(監聽) 高4位為COL(輸出,低電平)
//	7	6	5	4	3	2	1	0    
// Co4 Co3 Co2 Co1 Ro4 Ro3 Ro2 Ro1

/*	COL 4 3 2 1
	ROW	4
		3
		2
		1
*/

unsigned char row=0,col=0;


//<返回其列號(col) 需要事先準備其行號掩碼>
static unsigned char Matrix_Key_Scan_Col(const unsigned char rowbitmask)
{
	unsigned char i=0;
	unsigned char colmask;
	KEY_PINS = 0x0f;
	colmask=0x0f;
	while ( (KEY_PINS & rowbitmask)==0)
	{
		colmask = colmask<<1;
		KEY_PINS = colmask | 0x0f;
		i++;
	}
	return i;
}


//<檢測是否有按鍵按下,并返回其行號(row)>
static unsigned char Matrix_Key_Scan_Row()
{
	KEY_PINS = 0x0f;
	
	if (ROW1 == 0)
	{
		return 1;
	}
	else if (ROW2 == 0)
	{
		return 2;
	}
	else if (ROW3 == 0)
	{
		return 3;
	}
	else if (ROW4 == 0)
	{
		return 4;
	}
	return 0;
}

unsigned char Matrix_Key_Detect()	//行/列
{
	static unsigned char keep_time;
	static unsigned char keep_row;
	static unsigned char keep_col;
	static unsigned char state		= 0;
	unsigned char uScanReturn;

	switch (state)
	{
		case 0:	//檢測是否有按鈕按下
			if (Matrix_Key_Scan_Row() != 0 )
			{	//<初始化>
				keep_time	= 0;
				keep_row	= 0;
				keep_col	= 0;
				state++;
			}
			break;
		case 1:
			uScanReturn = Matrix_Key_Scan_Row();
			if (uScanReturn != 0 )	//按鍵按下姿態
			{
				if (keep_time<250) keep_time++;
				if (keep_row == 0) 
				{
					keep_row = uScanReturn;
				}
				if (keep_row != 0 && keep_col == 0)
				{
					keep_col = Matrix_Key_Scan_Col( 0x01<<(keep_row-1) );
				}
			}
			else					//按鍵松起姿態
			{
				if (keep_time>5)	//檢測到有效按鍵
				{
					keep_time = 0;
					state++;
				}
				else				//按鍵無效
				{
					state = 0;
				}
			}
			break;
		case 2:
			if (Matrix_Key_Scan_Row() == 0 )		//按鍵松起姿態(保持)
			{
				if (keep_time<250) keep_time++;
				if (keep_time>5)	//檢測到有效松起
				{
					/* 返回信息：檢測到有效按鍵，并可以執行對應操作 */
					state = 0;
					row = keep_row;
					col = keep_col;
					return 1;
				}
			}
			else	//按鍵被重新按下
			{
					keep_time=0;	//重新計時
			}
			break;
	}
	return 0;

}