read from I2C

Posted by Steffen2

on Jul 23 2009 04:15 AM

Hi, I need some help with using the I2C functions when reading.
I think there is a general problem...
thank you

Code:



 
char I2C_read(char slave_address, char reg_address){
  char DATA;
  
  //DISABLE INTERRUPTS
  IntDisable(I2C0_MASTER_BASE);
  
  I2CMasterSlaveAddrSet(I2C0_MASTER_BASE, slave_address, true); 
  
//BufferIn(reg_address);

  I2CMasterDataPut(I2C0_MASTER_BASE, reg_address);
  
  I2CMasterControl(I2C0_MASTER_BASE,    I2C_MASTER_CMD_SINGLE_RECEIVE);      
  while(I2CMasterBusy(I2C0_MASTER_BASE))
  {
  }
  
  DATA = I2CMasterDataGet(I2C0_MASTER_BASE);
  //ENABLE INTERRUPTS
  IntEnable(I2C0_MASTER_BASE);

  return DATA;      
  
}

Posted by wella - Martin Velek

on Jul 23 2009 04:43 AM

Expert2105 points

Try this code:
I have changed char to unsigned char and added some additional function calling.

unsigned char I2C_read(char slave_address, char reg_address){

unsigned char DATA;

//DISABLE INTERRUPTS

IntDisable(I2C0_MASTER_BASE);

I2CMasterSlaveAddrSet(I2C0_MASTER_BASE, slave_address, false);

//BufferIn(reg_address);

I2CMasterDataPut(I2C0_MASTER_BASE, reg_address);

I2CMasterControl(I2C0_MASTER_BASE, I2C_MASTER_CMD_BURST_SEND_START);

while(I2CMasterBusy(I2C0_MASTER_BASE))

{

}
I2CMasterSlaveAddrSet(I2C0_MASTER_BASE, slave_address, true);

I2CMasterControl(I2C0_MASTER_BASE, I2C_MASTER_CMD_SINGLE_RECEIVE);

while(I2CMasterBusy(I2C0_MASTER_BASE))
{

}

DATA = I2CMasterDataGet(I2C0_MASTER_BASE);

//ENABLE INTERRUPTS

IntEnable(I2C0_MASTER_BASE);

return DATA;

}

Posted by Steffen2

on Jul 23 2009 06:17 AM

Prodigy70 points

thanks, this code works :)

Posted by A Newbie

on Apr 26 2012 05:14 AM

Prodigy150 points

Hello Martin,

I tried implementing master read portion of your code. My control never comes out of

while(I2CMasterBusy(I2C0_MASTER_BASE))
{

}

Any possible reason you could think of?

Thanks