ds18b20.c

温度传感ic18b02源码

#include "reg52.h"
#include <intrins.h>

#define	Ds18b20 1

#define	Standard 1
#define	uint unsigned int
#define	uchar unsigned char			  
#define	Clock	12//18.324
		//18.324M	  
#define	D_D	4*Clock/8
#define	A	6*Clock/8
#define	B	64*Clock/8
#define C	60*Clock/8
#define	D	10*Clock/8
#define	E	4*Clock/8
#define F	55*Clock/8
#define G	0*Clock/8
#define	H	480*Clock/8				 
#define	I	70*Clock/8
#define J	410*Clock/8

sbit	DQ=P2^2;
sbit	test=P2^3;

void	Delay(uint a)	//8个state
{
	while(a)
	a--;
 

}

void WriteBit(bit Num)
{	//EA=0;
	if (Num)
	{
		// Write '1' bit
		DQ=0;			// Drives DQ low
		Delay(D_D);
		DQ=1; 			// Releases the bus
		Delay(B);   	// Complete the time slot and 10us recovery
	}
	else
	{
		// Write '0' bit
		DQ=0; 			// Drives DQ low
		Delay(C);
		DQ=1;		 	// Releases the bus
		Delay(D);
	}
	//EA=1;
}
bit	Reset(void)
{	
	bit result;
	//EA=0;
	Delay(G);
	DQ=0;				 // Drives DQ low
	Delay(H);
	DQ=1; 				// Releases the bus
	Delay(I);

	result= DQ;			 // Sample for presence pulse from slave
	Delay(J); 			// Complete the reset sequence recovery
	DQ=1;
	//EA=1;
	return result;			 // Return sample presence pulse result
}

/*bit ReadBit(void)
{
	bit result;

	DQ=0; 		// Drives DQ low
	Delay(A);
	//DQ=1;		// Releases the bus
	P1M1|=0x1;		
	//P1M2=0;
	Delay(E);
	result= DQ; 	// Sample the bit value from the slave
	Delay(F); 		// Complete the time slot and 10us recovery
	P1M1&=0xfe;
	DQ=1;
	return result;
}
*/
bit ReadBit(void)
{
	bit result;
	//EA=0;
	DQ=0; 		// Drives DQ low
	Delay(D_D); 	
	DQ=1;		// Releases the bus
	Delay(D_D);
	result= DQ; 	// Sample the bit value from the slave
	Delay(F); 		// Complete the time slot and 10us recovery
	//EA=1;
	return result;
}
void WriteByte(uchar databuf)
{
	uchar	loop;
	for (loop = 0; loop < 8; loop++)
	{
		WriteBit(databuf & 0x01);
		databuf >>= 1;
	}
}

uchar ReadByte(void)
{
	uchar loop, result=0;

	for (loop = 0; loop < 8; loop++)
	{
		result >>= 1;
		if (ReadBit())
			result |= 0x80;
	}
	return result;
}

struct Page0{
			   uchar Teml;
			   char Temh;
			   uchar Voll;
			   uchar Volh;
			   uint	 Cur;
			   uchar ThresHold;
			   uchar CrcCode;
			   uchar state;
			};
struct Page0 idata *PPage0;


uchar   data page_data[9];
uint	VolValue,CurValue,IntTemValue;
float		TemValue;
uchar ICA;


uchar ReadPage()
{
	uchar i;
	if (Reset()) 	// Reset the 1-Wire bus
		return 0; 	// Return if no devices found
	WriteByte(0xcc);
	WriteByte(0x44);
	while(!ReadBit());
	Reset();
    WriteByte(0xcc);
	WriteByte(0xbe);   
	
	

								// read the page data
	for (i = 0; i <9; i++)
		page_data[i] = ReadByte();
	Reset();
	PPage0=(struct Page0 idata *)page_data;
	if(PPage0->Temh<0)
	{
		IntTemValue=PPage0->Temh*(-1)*0x100+PPage0->Teml;//PPage0->Teml&0x1f*0.0625;	//PPage0->Temh*(-1)+(float)(PPage0->Teml>>=4)*0.125;
		TemValue=(IntTemValue%16)*0.0625+IntTemValue/16;
	}
	else
	{
		IntTemValue=PPage0->Temh*0x100+PPage0->Teml;
		TemValue=(IntTemValue%16)*0.0625+IntTemValue/16;
	}

		
	if (Reset()) 				// Reset the 1-Wire bus
		return 0;
	return 1;
}