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I2C Read Function

Kenton Phillips
Prodigy 200 points

I am trying to read 6 bytes of data from an encoder and store them to an array, for my example write_data[i]. However, I do not know how to write the function that initiated the IC2 rountine to receive the data from the input. Once I have the values in an array I know how to proceed.

void I2CA_ReadData(void)

{

" NEED HELP HERE"

AGC=write_data[0];
error_status=write_data[1]&0x0F;
MAG =(write_data[2]<<6)+(write_data[3]&0x3F);
ANG =(write_data[4]<<6)+(write_data[5]&0x3F);

return;

}

  • 0
    Guru 192875 points

    Hi Kenton,

    Here's a I2C read subroutine, hope you find it useful:

    Fullscreen 1200.i2c_read function.txt Download 
    Uint16 I2CA_ReadData(struct I2CMSG *msg)
{
   // Wait until the STP bit is cleared from any previous master communication.
   // Clearing of this bit by the module is delayed until after the SCD bit is
   // set. If this bit is not checked prior to initiating a new message, the
   // I2C could get confused.
   if (I2caRegs.I2CMDR.bit.STP == 1)
   {
      return I2C_STP_NOT_READY_ERROR;
   }

   I2caRegs.I2CSAR = msg->SlaveAddress;

   if(msg->MsgStatus == I2C_MSGSTAT_SEND_NOSTOP)
   {
      // Check if bus busy
      if (I2caRegs.I2CSTR.bit.BB == 1)
      {
         return I2C_BUS_BUSY_ERROR;
      }
      I2caRegs.I2CCNT = 2;
      I2caRegs.I2CDXR = msg->MemoryHighAddr;
      I2caRegs.I2CDXR = msg->MemoryLowAddr;
      I2caRegs.I2CMDR.all = 0x2620;			// Send data to setup EEPROM address
   }
   else if(msg->MsgStatus == I2C_MSGSTAT_RESTART)
   {
      I2caRegs.I2CCNT = msg->NumOfBytes;	// Setup how many bytes to expect
      I2caRegs.I2CMDR.all = 0x2C20;			// Send restart as master receiver
   }

   return I2C_SUCCESS;
}

    Regards,

    Gautam