mini2440 I2C

Hello team,

I'm using the following code in mini2440 and the write function is always
returning -1:

/////////////////////////////////////////////////////////
...
fd=open("/dev/i2c/0", O_RDWR);
  if(fd<0)
  {
    printf("Error open!\n");
  }

  buf[0]=0x00;
  buf[1]=0xff;

  io=ioctl(fd,0x703,0x50);
  if(io<0)
  {
    printf("Error ioctl!\n");
  }

  wbyte=write(fd,buf,2);
  if(wbyte!=1)
  {
    printf("Wbyte: %d\n",wbyte);
    printf("Error write!\n");
  }
...
////////////////////////////////////////////////////////

Am I doing anything wrong?



Best Regards, Leandro Ribeiro.

You can try to add more specific error string. Something like:
wbyte=write(fd,buf,2);

if (wbyte < 0) {
     perror("write");
}

You can post then output.

OK, thanks! I'm doing it now.
But it is always returning -1.
Why I can't write at the bus?
Is it necessary to connect a device in the bus or I can write without any
device just for testing?

If the device doesn't acknowledge the transfer then the result will be -1.

I used that to scan all the addresses to see which addresses where in
use...

Thus if the device is not connected or you are using the wrong address then
you will get -1.

Thanks,
Errol

Thanks, that's it.

I have connect MINI2440 with electronic compass (HMC5843) 
and run i2c example program with below contruction 
and then I got that below error,..that seem MINI2440 can't see my device
........What wrong ??? help me please

mini2440:/usr/local/Qt/Project/i2c# ./i2c -r                               
    
Open /dev/i2c-0 with 8bit mode                                             
    
  Reading 256 bytes from 0x0                                               
    
Error i2c_write_1b: No such device or address                              
    
Error at line 48: read error                                               
    
        sysmsg: No such device or address                                  
    
mini2440:/usr/local/Qt/Project/i2c# ./i2c -w                               
    
Open /dev/i2c-0 with 8bit mode                                             
    
  Writing 0x00-0xff into 24C08                                             
    
                                                                           
    
 0000|  00 Error i2c_write_2b: No such device or address                   
    
Error at line 71: write error                                              
    
        sysmsg: No such device or address

Did You set correct device address? You can find it in documentation.

good luck
Tom

hello experts,
i need the min2440 documentation(all).
can anyone provide it to me because ftp:/ server site cannot respond.
i tried many times but error occured.
thank you.

Hello r@wboom,
    You can send email to me ,I will give you the newest zimage .My email
is jiameijiang@friendlyarm.com

hello 
can anyone tell me...why we use ioctl(fd, 0X703, 0X50).
as 0X703 ans 0X50;
i didn't understand.

hello friends,
please help me i only want to know what type of address of this...
0x703 and 0x50;

hello all.
can anyone help why we have to set like this 

buf[0]=0x00;
buf[1]=0xff;

what is it means?