/*
 * $Id: keybd.c,v 1.2 2003/08/29 03:13:16 casic Exp $
 *
 * keybd.c : keyboard driver
 *
 * Copyright (C) 2003 ynding ( haoanian@263.net )
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include "ep7312.h"
#include "keybd.h"
#include "wait.h"

/* define the meaning of each key on the keyboard */
static char key[ROW][COL] = {
	{'1','2','3','a'},
	{'4','5','6','b'},
	{'7','8','9','c'},
	{'*','0','#','d'}
};

/* initialize keyboard */
void init_keybd(void)
{
	rPADDR |= 0x00;

	rSYSCON2 |= 0x00000008;
	rSYSCON1 |= 0x00000008;

	return;
}

/* 
 * keyboard scan, capture key pressed
 * block : block or non-block
 */
char keyscan()
{
	unsigned long pa_value;	/* store the value read from the PA port */
	unsigned long column = 0x000000008; /* write the value of column to SYSCON1,
					       the initial value 0x8 will cause the 
					       voltage of col0 to high */
	char keyvalue = 'x';	/* while keyvalue == 'x', means that no key is pressed */

	int col = 0;

	/* will loop until there is a key pressed */

		/* initial the variables before each loop of keyboard scan */
		keyvalue = 'x';
		column = 0x00000008;

		/* this for loop execute a single loop for keyboard scanning,
		   from col0 to col3:
		   firstly, set col0 to high, others to low ,
		   then, set col1 to high, others to low, and so on */
		for ( col=0;col<4;++col ) {
			int row = 0;

			rSYSCON1 &= ~0x0000000f;
			rSYSCON1 |= column;
	
			wait(20);
	
			rPADDR |= 0x00;	/* set PA port as input */
			pa_value = rPADR;/* read data from PA port */
			pa_value &= 0xf;/* take out the value useful to us */
                    if ( pa_value != 0 ){wait(50);

                                              }
                     pa_value = rPADR;/* read data from PA port */
			pa_value &= 0xf;/* take out the value useful to us */


			if ( pa_value != 0 ) {	/* means there is a key pressed */
				/* this for loop determines which key is pressed */ 
				for ( row=0;row<4;++row ) {
					if ( (pa_value >> row) & 0x1 ) {
						keyvalue = key[row][col];
						break;
					}
				}
			}

			if ( keyvalue != 'x' )
				break;

			++column;
		}


	wait(100);
	
	return keyvalue;
}