/**
  ******************************************************************************
  * @file    tim.c 
  * @author  Jerry
  * @version V2.1
  * @date    19-April-2022
  * @brief   tim program body.
  ******************************************************************************
  * @attention
  *
  *
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "stm32f10x.h"
#include "global.h"

//相对精确的ms延时，不使用中断
//优化：防止和其他中断冲突，导致卡死
void delay_ms(uint16_t ms)
{
	uint16_t i;
	volatile uint32_t tempreg;
	
	uint32_t timeout; //等待时间
	
	for(i=0; i<ms; i++)
	{
		SysTick->CTRL |= SysTick_CTRL_CLKSOURCE_Msk;
		SysTick->LOAD = 72000 - 1;
		SysTick->VAL = 0;
		SysTick->CTRL |= SysTick_CTRL_ENABLE_Msk;
		timeout = 72000;
		do
		{
			tempreg = SysTick->CTRL;
			
			timeout--;
			if(timeout == 0) 
			{
					break; //超时退出
			}
		}
		while( (tempreg & SysTick_CTRL_COUNTFLAG_Msk) ==0); 
		
		SysTick->CTRL &= ~SysTick_CTRL_ENABLE_Msk;
		SysTick->VAL = 0;  
	}
}

//相对精确的us延时，不使用中断
//(没调用过)
void delay_us(uint16_t us)
{		
	uint16_t i;
	volatile uint32_t tempreg;
	
	for(i=0; i<us; i++)
	{
		SysTick->CTRL |= SysTick_CTRL_CLKSOURCE_Msk; 
		SysTick->LOAD = 72;       
		SysTick->VAL = 0;            
		SysTick->CTRL |= SysTick_CTRL_ENABLE_Msk;    
		do
		{
			tempreg = SysTick->CTRL;
		}
		while( (tempreg & SysTick_CTRL_COUNTFLAG_Msk) ==0); 
		
		SysTick->CTRL &= ~SysTick_CTRL_ENABLE_Msk;
		SysTick->VAL = 0;  
	}	 
}