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Little explanation for the i2c eeprom example

Nicolas Sizorn
Prodigy 175 points
Other Parts Discussed in Thread: TMS320F28035

Someone can help me to understand this example on a TMS320F28035 ?

Ok, when I launch it no problem everyting works.

But I don't really understand WHERE the data is written...

Indeed, in the I2cMsgOut1 struct I have two adresses : I2C_EEPROM_HIGH_ADDR and I2C_EEPROM_LOW_ADDR (0x00 & 0x30) then I have two data to write (0x12 & 0x34)

then in the "I2CA_WriteData" function I can see this code who write the data on the I2C bus :

I2caRegs.I2CDXR = msg->MemoryHighAddr;
I2caRegs.I2CDXR = msg->MemoryLowAddr;
// for (i=0; i<msg->NumOfBytes-2; i++)
for (i=0; i<msg->NumOfBytes; i++)

{
      I2caRegs.I2CDXR = *(msg->MsgBuffer+i);
}

So if I understand the datas send on the I2C bus are  => I2C_ADDR 0x00 0x30 0x12 0x34 ? I'm right ?

So where are stored my datas ? is Adresse 0x00 ==0x12 and 0x30 ==0x34 ? OR adresse 0x30 ==0x12 and 0x31 == 0x34 ??

Thank you.

Best regards, Nicolas

  • 0
    Expert 1345 points

    Nicolas,

    The data is stored in MsgBuffer[i] with i ranging from 0 to I2C_MAX_BUFFER_SIZE.

    If you watch I2cMsgIn1.MsgBuffer[i] and I2cMsgOut1.MsgBuffer[i] in the Expression watch window, you will see the values.

    -Chuck

  • 0 in reply to Charles Jackel
    Intellectual 370 points
    Hi Nicalos,
    It saves in address 0x0030 and 0x0031, this is correct until only your eeprom requires 2 bytes for address.
    ex : 1)24LC16B requires only 1 address byte with above program whatever you send will go to default 0x00 and so on.
    2)24LC32 requires only 2 address byte with above program whatever you send will go to default 0x0030 and so on.

    Regards
    LT