#include "delay.h"

static uint8_t  UsNumber=0;							   
static uint16_t MsNumber=0;							

void Delay_Init()
{
	RCC_ClocksTypeDef clocks;
	RCC_GetClocksFreq(&clocks); //??????
	SysTick_CLKSourceConfig(SysTick_CLKSource_HCLK_Div8);	
	UsNumber=clocks.HCLK_Frequency/HSE_VALUE;				
	MsNumber=(u16)UsNumber*1000;							
}								    

    								   
void Delay_Us(u32 nus)
{		
	u32 temp;	    	 
	SysTick->LOAD=nus*UsNumber; 						 
	SysTick->VAL=0x00;        					
	SysTick->CTRL|=SysTick_CTRL_ENABLE_Msk ;	
	do
	{
		temp=SysTick->CTRL;
	}while((temp&0x01)&&!(temp&(1<<16)));		
	SysTick->CTRL&=~SysTick_CTRL_ENABLE_Msk;	
	SysTick->VAL =0X00;      					
}

void Delay_Ms(u16 nms)
{	 		  	  
	u32 temp;		   
	SysTick->LOAD=(u32)nms*MsNumber;				
	SysTick->VAL =0x00;							
	SysTick->CTRL|=SysTick_CTRL_ENABLE_Msk ;	
	do
	{
		temp=SysTick->CTRL;
	}while((temp&0x01)&&!(temp&(1<<16)));		
	SysTick->CTRL&=~SysTick_CTRL_ENABLE_Msk;	
	SysTick->VAL =0X00;       					
}