ds18b20.c

在mdk下面实现对于ds18b20的控制

/*********************************************************************************************
* File:		Temperature_test.c
* Author:	embest
* Desc:		Temperature_test 
* History:	
*********************************************************************************************/

/*------------------------------------------------------------------------------------------*/
/*                                     include files	                                    */
/*------------------------------------------------------------------------------------------*/
#include "2410lib.h"
#include "math.h"

/*------------------------------------------------------------------------------------------*/
/*                                     constants define                                     */
/*------------------------------------------------------------------------------------------*/

#define DQ GPIO11
#define CFG_IN 0x0
#define CFG_OUT 0x1
#define Warning 30
#define uchar  unsigned char
#define rCPLDLEDADDR  (*(volatile unsigned char*)0x21140000) 			// LED Address
extern void iic_write_8led(UINT32T unSlaveAddr,UINT32T unAddr,UINT8T ucData);
extern void iic_init_8led(void);
unsigned char f_szDigital[10] ={0xFC,0x60,0xDA,0xF2,0x66,0xB6,0xBE,0xE0,0xFE,0xF6};	// 0 ~ 9
/*********************************************************************************************
* name:		beep_on_off
* func:		beep_on_off test
* para:		none
* ret:		none
* modify:			   
* comment:		
*********************************************************************************************/
void beep_on_off(int time)
{
	int i;	
	rCPLDLEDADDR = 0x00;
	for(i = 0; i < 10000/time; i++);
	rCPLDLEDADDR = 0xFE;
	for(i = 0; i < 10000/time; i++);
}

/*********************************************************************************************
* name:		udelay
* func:		delay (num*2+10) us
* para:		num
* ret:		
* modify:
* comment:		
*********************************************************************************************/
 void udelay(int num)
{	   
	int i;
 	for(i=0; i < num;i++);
}
/*********************************************************************************************
* name:		s3c2410_gpio_cfgpin
* func:		set the pin for out or in
* para:		state
* ret:		none
* modify:
* comment:		
*********************************************************************************************/

void s3c2410_gpio_cfgpin(int state)
{	
	if(state == CFG_IN)
		rGPECON = (rGPECON & 0xff3fffff) | 0x00000000; //set GE11
	else
		rGPECON = (rGPECON & 0xff3fffff) | 0x00400000; //set GE11
		
}
/*********************************************************************************************
* name:		s3c2410_gpio_pullup
* func:		enable or disable the pull up function
* para:		state
* ret:		none
* modify:
* comment:		
*********************************************************************************************/

void s3c2410_gpio_pullup(int state)
{
	if(state == 0)
		rGPEUP  = rGPEUP & 0xf7ff;
	else
		rGPEUP  = rGPEUP | 0x0800;	
}
/*********************************************************************************************
* name:		s3c2410_gpio_setpin
* func:		set io pin
* para:		the pin state
* ret:		none
* modify:
* comment:		
*********************************************************************************************/
void s3c2410_gpio_setpin(int bit)
{
	if(bit == 0)
		rGPEDAT  = rGPEDAT & 0xf7ff;
	else
		rGPEDAT  = rGPEDAT | 0x0800;
	
}
/*********************************************************************************************
* name:		s3c2410_gpio_getpin
* func:		get the state of io pin.
* para:		none
* ret:		none
* modify:
* comment:		
*********************************************************************************************/

int s3c2410_gpio_getpin(int dq)
{	
	if((rGPEDAT & 0x0800) == 0x0) 
		return 0;
	else 
		return 1;
}
/*********************************************************************************************
* name:		ds18b20_reset
* func:		ds18b20 test
* para:		none
* ret:		none
* modify:
* comment:		
*********************************************************************************************/

int ds18b20_reset(void)      				//ds18b20复位，返回0成功，返回1失败
{
	int ret;
	s3c2410_gpio_cfgpin(CFG_OUT);
  	s3c2410_gpio_pullup(0);
	s3c2410_gpio_setpin(0);                	//拉低数据线电平
	udelay(300);          					//精确延时480us-960us
	s3c2410_gpio_setpin(1);                	//拉高电平
	udelay(25);           					//精确延时15us-60us
	s3c2410_gpio_cfgpin(CFG_IN);
  	ret = s3c2410_gpio_getpin(DQ);
  	if(ret)
  	{
 		uart_printf(" Error\n");
		return -1;
	}
	else
	{
	//	uart_printf("OK!");
		udelay(40);
	}
	return ret; 
}

/*********************************************************************************************
* name:		write_byte
* func:		write a byte data to ds18b20
* para:		data
* ret:		none
* modify:
* comment:		
*********************************************************************************************/

void write_byte(unsigned char data)//向18b20写一个字节
{
  char i = 0;
  s3c2410_gpio_cfgpin(CFG_OUT);
  s3c2410_gpio_pullup(0);
  for(i=0; i<8; i++){	
  	s3c2410_gpio_setpin(1);
	i = i;
    s3c2410_gpio_setpin(0);
    //udelay(2);
	udelay(1);
    s3c2410_gpio_setpin(data&0x01);
    udelay(25);
    data >>= 1;
  }
  s3c2410_gpio_setpin(1);
}
/*********************************************************************************************
* name:		read_byte
* func:		read a byte data from ds18b20
* para:		none
* ret:		none
* modify:
* comment:		
*********************************************************************************************/

unsigned char read_byte(void)//从18b20读一个字节
{
  unsigned char i;
  unsigned char data=0;
  s3c2410_gpio_cfgpin(CFG_OUT);
  s3c2410_gpio_pullup(0);
  for(i=0; i<8; i++)
    { 
	  data >>= 1;
	  s3c2410_gpio_cfgpin(CFG_OUT);
	  //s3c2410_gpio_setpin(1);
	  //udelay(6);
      s3c2410_gpio_setpin(0);
      i = i;
      s3c2410_gpio_setpin(1);
	  i = i; 
      s3c2410_gpio_cfgpin(CFG_IN);  
      if(s3c2410_gpio_getpin(DQ))
    		data |= 0x80;
	  else
	  		data &= 0x7f;
    //  udelay(2);
      //s3c2410_gpio_cfgpin(CFG_OUT);
      //s3c2410_gpio_pullup(0);
      //s3c2410_gpio_setpin(1);
      //
    }	
  udelay(2);
 // s3c2410_gpio_cfgpin(CFG_OUT);
 // s3c2410_gpio_pullup(0);
 // s3c2410_gpio_setpin(1);
  return data;
}
						  
 
/*********************************************************************************************
* name:		temperature_test
* func:		temperature test
* para:		none			
* ret:		none
* modify:
* comment:		
*********************************************************************************************/
void temperature_test() 
{ 
	unsigned int a = 0, b = 0,t = 0;
	float tt;
	int temp = 0,ret,i;
	uart_printf(" Temperature Test!\n");
	s3c2410_gpio_cfgpin(CFG_OUT);
	iic_init_8led();
	do{ 
		ret = ds18b20_reset();
		if (ret == -1) 
			return ;
		write_byte(0xcc);
		write_byte(0x44);
		udelay(1000*800);
		ds18b20_reset();
		write_byte(0xcc);
		write_byte(0xbe);

		a = read_byte();
		b = read_byte(); 
				
		t = b;
		t <<= 8;
		t = t | a;

		tt = t * 0.0625;
   		tt = tt * 1 + 0.5; //放大10倍输出并四舍五入
		uart_printf(" The current temperature is: %5.4fC\r",tt);
		temp = (int)tt;
		iic_write_8led(0x70, 0x10, f_szDigital[(temp%10)]);	 //0
		iic_write_8led(0x70, 0x11, f_szDigital[temp/10]);
		if (temp >= Warning)
		{	 		
			for(i = 0; i < 10; i++ )
			{ 	
				iic_write_8led(0x70, 0x12, f_szDigital[8]);
				beep_on_off(temp);
				udelay(1000);
				iic_write_8led(0x70, 0x12, f_szDigital[0]);
				beep_on_off(temp);
				udelay(1000);
			}
		}
	}while(1); 
}