#include "delay.h"

static uint8_t  fac_us=0;//usÑÓʱ±¶³ËÊý
static uint16_t fac_ms=0;//msÑÓʱ±¶³ËÊý

void delay_init(uint32_t sysclkfre)
{
//	CMU->SYSCLKCR &= SYSTICK_CLOCK_SOURCE_SYSCLK;//systick¹¤×÷ʱÖÓÑ¡Ôñsysclk 
//	CMU_SYSCLKCR_STCLKSEL_Set(0x00000003);//¿âº¯Êý
	CMU->SYSCLKCR &= ~SYSTICK_CLOCK_SOURCE_U_SYSCLK;
	CMU->SYSCLKCR |= SYSTICK_CLOCK_SOURCE_U_SYSCLK;
	fac_us=sysclkfre/1000000;;	//ΪϵͳʱÖÓµÄ1/12  
	fac_ms=(uint16_t)fac_us*1000;//ÿ¸ömsÐèÒªµÄsystickʱÖÓÊý 	
}

void delay_ms(uint32_t ms)
{
	uint32_t temp;		   

	SysTick->LOAD=(uint32_t)ms*fac_ms;//ʱ¼ä¼ÓÔØ(SysTick->LOADΪ24bit)
	SysTick->VAL =0x00;           //Çå¿Õ¼ÆÊýÆ÷
	SysTick->CTRL|=SysTick_CTRL_ENABLE_Msk ;          //¿ªÊ¼µ¹Êý  
	do
	{
		temp=SysTick->CTRL;
	}
	while(temp&0x01&&!(temp&(1<<16)));//µÈ´ýʱ¼äµ½´ï   
	SysTick->CTRL&=~SysTick_CTRL_ENABLE_Msk;       //¹Ø±Õ¼ÆÊýÆ÷
	SysTick->VAL =0X00;       //Çå¿Õ¼ÆÊýÆ÷	 
}

void delay_us(uint32_t us)
{
	uint32_t temp;	    	 
	SysTick->LOAD=us*fac_us; //ʱ¼ä¼ÓÔØ	  		 
	SysTick->VAL=0x00;        //Çå¿Õ¼ÆÊýÆ÷
	SysTick->CTRL|=SysTick_CTRL_ENABLE_Msk ;          //¿ªÊ¼µ¹Êý	 
	do
	{
		temp=SysTick->CTRL;
	}
	while(temp&0x01&&!(temp&(1<<16)));//µÈ´ýʱ¼äµ½´ï   
	SysTick->CTRL&=~SysTick_CTRL_ENABLE_Msk;       //¹Ø±Õ¼ÆÊýÆ÷
	SysTick->VAL =0X00;       //Çå¿Õ¼ÆÊýÆ÷	 
}