dip4.c

开发板外设接口实验（1～7）

/*
 *	dip4.c   -  dip4 api & driver 
 *	
 *	Author: 	li ming <[e-mail]>
 *	Date:		2008-4-16
 *	Copyleft:	http://www.lumit.org
 */
 
#include "dip4.h"

/*  
; hardware connection
; PIO0 	PIO1 	PIO2 	PIO3	(gpio)
; 1  	2   	3   	4 	(dip4)
; so output value = 0x0000000f = (0b0000 0000  0000 0000  0000 0000  0000 1111)
*/

/* define the relative gpio register */
#define SYSCFG      0x03FF0000
#define IOPMOD		(*((volatile unsigned *)(SYSCFG+0x5000)))
#define IOPDATA		(*((volatile unsigned *)(SYSCFG+0x5008)))

/* set dip4 related gpio */
int dip4_init(void)
{
	// External interrupt 0 source number is 0
	// set gpio's direction: set IOPMOD register mode bit to 0 = input
	IOPMOD = IOPMOD & (~0x0000000F);
	
	return 0;
}

int dip4_is_down(int position)
{ 
	if(IOPDATA & (1 << position))
		return 0;	
	
	return 1;
} 

int dip4_is_up(int position)
{ 
	if(IOPDATA & (1 << position))
		return 1;	
	
	return 0;
} 

int status = 0;
	 
int dip4_test(void)
{
	int i = 0;
	
	dip4_init();
	
	for(i = 0; i < 4; i++)
	{
		status = dip4_is_up(i);
		status = dip4_is_down(i);
	}	
	return status;
}