timer.c

来自「开发板外设接口实验（1～7）」· C语言 代码 · 共 59 行

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

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

// timer mode register
#define TMOD			(*((volatile unsigned *)(SYSCFG+0x6000)))  
#define TDATA0		(*((volatile unsigned *)(SYSCFG+0x6004)))
#define TCNT0			(*((volatile unsigned *)(SYSCFG+0x600c)))

/* set timer related gpio */
int timer_init(void)
{
	/* enable timer 0 */
	TMOD = 1;
	
	return 0;
}

int timer_get_value(void)
{ 	
	return TCNT0;
} 

int timer_set_value(int value)
{ 
	TCNT0 = value;
		
	return 0;
} 

int timer_test(void)
{
	int t = 0;
	
	timer_init();
	
	// 1s = 50Mhz (0x3200000)	
	timer_set_value(0x3200000);
		
	while(1)
	{
		t = timer_get_value();
		if(t <= 0x1000)
			timer_set_value(0x3200000);
	}
	
	return 0;
}