📄 ds18b20.c
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//DATE 20071106
//ICCAVR ATMEGA16
/*DATE 20071006 crystal:3.6864MHZ;
for (i=100;i>0;i--) 250us
for (i=160;i>0;i--) 400us
for (i=190;i>0;i--) 500us
for (i=30;i>0;i--) 70us
for (i=25;i>0;i--) 60us
for (i=10;i>0;i--) 25us
for (i=5;i>0;i--) 15us
for (i=3;i>0;i--) 10us
for (i=2;i>0;i--) 7us
nop time 0.8us
*/
/*
Operation Description Implementation
Write 1 bit Send a '1' bit to the 1-Wire slaves (Write 1 time slot)
Drive bus low, delay A(5-15us) Recommended 6us;Release bus, delay B Recommended 64us(>59us)
Write 0 bit send a '0' bit to the 1-Wire slaves (Write 0 time slot)
Drive bus low, delay C 60us (60-120us);Release bus, delay D 10us(>8us)
Read bit Read a bit from the 1-Wire slaves (Read time slot)
Drive bus low, delay A 6us(5-15us) ;Release bus, delay E 9us(5-12us);
Sample bus to read bit from slave,Delay F 55us(>50us)
Reset Reset the 1-Wire bus slave devices and ready them for a command
Delay G 0(<2us);Drive bus low, delay H 480us(480-640us);Release bus, delay I 70us(63-78us);
Sample bus, 0 = device(s) present, 1 = no device present,Delay J 410us(>410us)
*/
/*
//测三个温度函数，由PORT口控制DS18B20 DATALINE（ATTENTION：NEED 4.7K Ohm），在ATMEGA8上通过
void Highds(dsnumb_temps)
{
switch ( dsnumb_temps )
{
case 1: HIGH_DSB(); break;
case 2: HIGH_DSB2(); break;
case 3: HIGH_DSB3(); break;
default: break;
}
}
void Lowds(dsnumb_temps)
{
switch ( dsnumb_temps )
{
case 1 : LOW_DSB() ; break ;
case 2 : LOW_DSB2() ; break ;
case 3: LOW_DSB3(); break;
default : break;
}
}
unsigned char CHKds(dsnumb_temps)
{
switch ( dsnumb_temps )
{
case 1: return( CHECKBIT(PINC,1) ) ; //break;
case 2: return( CHECKBIT(PINC,2) ) ; //break;
case 3: return( CHECKBIT(PINC,3) ) ; //break;
default: return( 0xee) ; //break;
}
}
*/
#include "main.h"
extern char bitdsb[64];
extern char bytedsb[8];
extern char bittc[72];
extern char bytetc[9];
extern int T_count;
extern char T_counth;
extern char T_countl;
//DS18B20
//#define LOW_DSB() CLEARBIT(PORTD, 7)
//#define HIGH_DSB() SETBIT(PORTD, 7)
//#define DATA_DSB() CHECKBIT(PORTE, 7)
unsigned char DS18B20_InitC(void)
{ int i=0;
for(i=0;i<5;i++)
{
HIGH_DSB();
NOP();
LOW_DSB();
for (i=190;i>0;i-- )//480us-960us
{ NOP(); }
HIGH_DSB(); //Release bus, delay 70us(63-78us)
for (i=0;i<30;i++)
{NOP();}
for(i=0;i<200;i++)
{
//if( CHECKBIT(PIND,7) ==0 )
if(!DATA_DSB())
{
i=200;
return(0x01);
}
else
{
if(i<180)
NOP();
if(i>180)
{
i=200;
return(0xff);
}
}
}
}
}
void DS18B20_Init(void)
{
unsigned char i=0;
unsigned char init=0;
init=DS18B20_InitC();
if(init==1)
for(i=0;i<3;i++)
{
{
HIGH_DSB();
NOP();
LOW_DSB();
for (i=190;i>0;i-- ) //480us-960us
{ NOP(); }
HIGH_DSB(); //Release bus, delay 70us(63-78us)
for (i=0;i<30;i++)
{NOP();}
for(i=0;i<200;i++)
{
//if( CHECKBIT(PIND,7) ==0 )
if(!DATA_DSB())
{
i=200;
break;
}
else
NOP();
}
}
for (i=165;i>0;i--)
{ NOP();}
i=200;
if(i==200)
break;
}
}
void DSBWriteByte( unsigned char dscommand )
{
unsigned char i,j,k;
for(i=0; i<8; i++)
{
if ( (dscommand & 0x01 )) //from low bit to high
{
HIGH_DSB();
NOP();
LOW_DSB(); //Drive bus low, delay (5-15us) Recommended 6us
for (k=2;k>0;k--)
{NOP();}
HIGH_DSB();
for (j=0;j<30;j++)
{ NOP(); }
NOP(); //Recovery Time
NOP();
NOP();
NOP();
NOP();
NOP();
}
else
{
HIGH_DSB();
NOP();
LOW_DSB(); //Drive bus low, delay 60us (60-120us)
for (j=0;j<30;j++)
{ NOP();}
HIGH_DSB(); // Release bus, delay 10us(>8us)
for (k=3;k>0;k--)
{NOP();}
}
dscommand >>= 1;
}
}
/*
For a read data time slot, if a “0” is to be transmitted,
the delay circuit determines how long the DS1990A will hold the data line
low overriding the 1 generated by the master.
If the data bit is a “1”, the iButton will leave the read data time slot unchanged.
Drive bus low, delay A 6us(5-15us) ;Release bus, delay E 9us(5-12us);
Sample bus to read bit from slave,Delay F 55us(>50us)
*/
void Read_DsB(void )
{
int i,j;
for(j=0;j<64;j++)
{ HIGH_DSB();
NOP();
LOW_DSB();
for (i=2;i>0;i--)
{NOP();}
HIGH_DSB();
for (i=2;i>0;i--)
NOP();
//if( CHECKBIT(PIND,7) )
if(DATA_DSB())
bitdsb[j]=1;
else
bitdsb[j]=0;
for (i=25;i>0;i--)
NOP();
NOP();
NOP();
NOP();
//putchar(bitdsb[j]);
//return(bitdsb[j]);
}
}
void Read_Dstc( void )
{
int i=0,j=0;
int m=0,n=0;
for(j=0;j<72;j++)
{ HIGH_DSB();
// Highds(dsnumb_temps);
NOP();
LOW_DSB();
//Lowds(dsnumb_temps);
for (i=2;i>0;i--)
{NOP();}
HIGH_DSB();
for (i=2;i>0;i--)
NOP();
//if( CHECKBIT(PIND,7))
if(DATA_DSB())
bittc[j]=1;
else
bittc[j]=0;
for (i=25;i>0;i--)
NOP();
NOP();
NOP();
NOP();
//putchar(bittc[j]);
}
for(m=8;m>=0;m--)
{
for(n=7;n>=0;n--)
{
bytetc[m] <<=1;
if(bittc[m*8+n]==1)
bytetc[m] |=0x01;
}
}
if(bytetc[1]&0x10)
{bytetc[1] = ~bytetc[1];
bytetc[0] = 0x10-bytetc[0];
T_count = (bytetc[1] << 8) + bytetc[0];
T_count = (T_count>>4)-1;
T_count|=0xff00; //ff msb sign'-'
//T_count = -T_count;
}
else
{ T_count = (bytetc[1] << 8) + bytetc[0];
T_count = T_count >> 4;
}
/*
for(j=8;j>=0;j--)
{
for(k=7;k>=0;k--)
{ bytetc[j] <<=1;
if(bittc[j*8+k]==1)
bytetc[j] |=0x01;
}
put0_char( bytetc[j]);
}
if(bytetc[1]&0x10)
{
//-25.0625 0xfe6f bytetc[1]=0xfe,bytetc[0]=0x6f
//msb is sign'-',lsb is decimal digits
//example ~0xfe=0x01,0x10-0x6f=0xa1;(0x01<<8)+0xa1=0x01a1;
//(0x01a1>>4)-1 = 0x001a-1=0x0019;(25)
//the least Significant bit 0x0001 is decimal digits(0.0625)
bytetc[1] = ~bytetc[1];
bytetc[0] = 0x10-bytetc[0];
T_count = (bytetc[1] << 8) + bytetc[0];
T_count = (T_count>>4)-1;
T_count = -T_count;
}
else
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