Three-Axis Digital Compass IC HMC5883L

[Siddique Ahmed Khan]

dear Bigdog,
I'm unable to convert the hex data to decimal. can you pls guide me.
I'm interfacing hmc 5883l with at89s52 in Keil U Vision 4.
thanks in advance

 

[bigdogguru]

Post or upload your code, so that it maybe reviewed.

BigDog

 

[Siddique Ahmed Khan]

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Code C - [expand]
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#include<reg51.h>
#define addwr 0x3c
#define addrd 0x3d
#define lcd P1
sbit scl=P3^6;
sbit sda=P3^7;
sbit rs=P3^5;
sbit en=P3^4;
unsigned int ch,ch0,ch1,ch2,ch3,ch4,ch5,a,b,c,d,e;
unsigned int b1,c1,d1,z1,z2,z3;
void lcddata();
 
 
void delay (unsigned int time)
{
unsigned int i,j;
for(j=0;j<time;j++)
for(i=0;i<=1275;i++);
} 
 
void start()
{
scl=1;
sda=1;
sda=0;
scl=0;
}
 
void ack()
{
sda=0;
scl=1;
scl=0;
sda=1;
}
 
void nack()
{
scl=1;
sda=1;
scl=0;
sda=0;
}
 
void stop()
{
scl=0;
sda=0;
sda=1;
scl=0; 
}
 
 
void i2c_out_byte(unsigned char o_byte)
{
unsigned int i;
for(i=0;i<8;i++)
      {
      
      if(o_byte & 0x80)
      {
            sda=1;
      }
      else
      {
            sda=0;
      }
      scl=1;
      scl=0;
      o_byte=o_byte<<1;
 
      }
      sda=1;
}
    
         
unsigned int i2c_in_byte(void)
{
unsigned int i_byte,i;
sda=1;
for(i=0;i<8;i++)
 {
    scl=1;
    if(sda==1)
         {
         i_byte=(i_byte<<1)|0x01;
         }
else
         {
         i_byte=(i_byte<<1);
         }
     scl=0;
  }
  return (i_byte);
 
}    
 
 
void lcdcmd(unsigned char ch)
{
 lcd=ch;
 rs=0;
 en=1;
 delay(1);
 en=0;
}
void lcddata(unsigned char ch)
{
 lcd=ch;
 rs=1;
 en=1;
 delay(1);
 en=0;
 
} 
void lcdinit()
{
 lcdcmd(0x38);
 delay(150);
 lcdcmd(0x0e);
 delay(150);
 lcdcmd(0x01);
 delay(150);
 lcdcmd(0x06);
 delay(150);
 }          
void adc_conversion1(unsigned int ch1)
{
      unsigned int kk;
  
        kk=ch1; 
    b1=kk%10;
    c1=kk/10;
    d1=c1%10;
    z1=c1/10;
    z2=z1%10;
    z3=z1/10;
 
    z2=z2|0x30;
    z3=z3|0x30;
    d1=d1|0x30;
    b1=b1|0x30;
//   lcdcmd(0x80);
    lcddata(z2);
    lcddata(z3);
    lcddata(d1);    
    lcddata(b1);    
}
 
void lcd_ser(unsigned char *ptr)
{
while(*ptr)
    {
    lcddata (*ptr++);
    }
}
    
 
 
 
void main()
{
 
lcdinit ();  
lcddata(0x80);
lcd_ser(" compass "); 
 
start();
i2c_out_byte(0x3c);
nack();
i2c_out_byte(0x00);
nack();
i2c_out_byte(0x70);
nack();
stop();
 
start();
i2c_out_byte(0x3c);
nack();
i2c_out_byte(0x01);
nack();
i2c_out_byte(0xA0);
nack();
stop();
 
start();
i2c_out_byte(0x3c);
nack();
i2c_out_byte(0x02);
nack();
i2c_out_byte(0x00);
nack();
stop();   
delay(6); 
    while(1)
    {
 
    lcdcmd(0x01);
 
 
 
//////////////////////////////////////////////reading all registers//////////////////
 
    start();
    i2c_out_byte(0x3d);
    nack();
    i2c_out_byte(0x06);
    nack();
 
    ch=i2c_in_byte();    //reading x msb
    ack();
    ch1=i2c_in_byte();   //reading x lsb
    ack();
    ch2=i2c_in_byte();   //reading y msb
    ack();
    ch3=i2c_in_byte();   //reading y lsb
    ack();
    ch4=i2c_in_byte();   //reading z msb
    ack();
    ch5=i2c_in_byte();   //reading z lsb
    nack();
    stop();
 
            
//////////////////////////////x axis conversion//////////////////
 
    
 
/*  ch=ch&0x00ff;       //conversion part
    ch=ch-0x01;
    ch=~ch;             //
                        //
                        //this is an experiment which i tried for converting the data of different axis
    a=ch&0x0f;          //
    b=ch&0xf0;          //
    c=(b*16)+a;
 
    lcdcmd(0x01);
    lcdcmd(0x80);
    adc_conversion1(c);
 
 
    ch1=ch1-1;
    ch1=~ch1;
 
    a=ch1&0x0f;
    b=ch1&0xf0;
    a=a*16*16;
    b=b>>4;
    b=b*16*16*16;
    d=a+b;
    e=d+c;
    lcdcmd(0xc0);
    adc_conversion1(e); */
 
    ch=(ch<<8)|ch1;
    adc_conversion1(ch);
 
///////////////////////////////////y axis conversion////////////////
 
    ch2=ch2&0x00ff;
    ch2=ch2-0x01;
    ch2=~ch2;
 
 
    a=ch2&0x0f;
    b=ch2&0xf0;
    c=(b*16)+a;
 
//  lcdcmd(0x01);
    lcdcmd(0x85);
    adc_conversion1(c);
 
 
    ch3=ch3-1;
    ch3=~ch3;
 
    a=ch3&0x0f;
    b=ch3&0xf0;
    b=b>>4;
    c=(a*10)+b;
    lcdcmd(0xc5);
    adc_conversion1(c);
 
/////////////////////////////////////////////z axis conversion////////////////
 
    ch4=ch4&0x00ff;
    ch4=ch4-0x01;
    ch4=~ch4;
 
 
    a=ch4&0x0f;
    b=ch4&0xf0;
    c=(b*16)+a;
 
//  lcdcmd(0x01);
    lcdcmd(0x8a);
    adc_conversion1(c);
 
 
    ch5=ch5-1;
    ch5=~ch5;
 
    a=ch5&0x0f;
    b=ch5&0xf0;
    b=b>>4;
    c=(a*10)+b;
    lcdcmd(0xca);
    adc_conversion1(c);
/////////////////////////////////////////sending 0x3c and 0x03 to start from beginning again/////////////
    start();
    i2c_out_byte(0x3c);
    nack();
    i2c_out_byte(0x03);
    nack();
    stop();
 
    delay(200);
    }  
}

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[Siddique Ahmed Khan]

thanks a lot for the instructions. will keep them in mind.:wink:

 

[Siddique Ahmed Khan]

hi bigdog,
did you find any errors in my code??
if yes pls update me so that i can correct them

 

[Siddique Ahmed Khan]

hi,
i'm getting the readings from the hmc5883l sensor. the problem was with the sensor. the program worked with a new sensor.

now i have a doubt. i.e. how should i convert the readings to +ve and -ve values in at89s52. for better understanding i'm typing a example below.

x: 15 y: -12 z: -131
x: 12 y: -15 z: -135
x: 14 y: -18 z: -132
x: 14 y: -16 z: -133