TMS320F28062: I2C repeat mode

dreja

Intellectual 350 points

Part Number: TMS320F28062

Hello,

I'm using a TMS320F28062 and I can succesfully send 4 bytes through I2C.

How can I send more than 4 bytes (for eg. 8 bytes), whithout a stop signal between them ?

The code for 4 bytes is the following:

   if (!I2caRegs.I2CSTR.bit.BB)   /* when the line is free */
    {
       I2caRegs.I2CFFTX.bit.TXFFRST=0;
       I2caRegs.I2CFFTX.bit.TXFFRST=1;
       for (i=0;i<4;i++)
       {
           I2caRegs.I2CDXR=(unsigned int)SndData[i]; /*FIFO*/
       }
       I2caRegs.I2CMDR.bit.MST=1; //set master mode
       I2caRegs.I2CMDR.bit.TRX=1; //set transmit mode
       I2caRegs.I2CCNT=4;       //set 4 bytes
       I2caRegs.I2CMDR.bit.STP=1; //set stop
       I2caRegs.I2CMDR.bit.STT=1; //set start
    }

If I want to send 8 bytes do I need to work in repeat mode ?

If yes, how do I modify the above source?

Thanks

Andrej

over 9 years ago

0 Adam Haun over 9 years ago

TI__Expert 8950 points

Andrej,

The easiest way is to set I2CCNT to 8. When the transmit FIFO is empty (I2CFFTX.TXFFST == 0), write four more bytes.

You can also use repeat mode if you'd like, but it doesn't really gain you anything in this case.

0 dreja over 9 years ago in reply to Adam Haun

Intellectual 350 points

Hi Adam,

thanks for your help. Now it works:

For sending / receiving the I2C data I'm periodically calling the "I2C refresh" procedure.

So when I need to send the 8 bytes, I do the procedure above (with the change that I load I2CCNT to 8 ).

Then, in the second pass, I don't check the if (!I2caRegs.I2CSTR.bit.BB) any more - I suppose the line is always busy, because the I2CCNT is still waiting for another 4 bytes.

So instead of that I load another 4 bytes as you suggested:

if (I2CFFTX.TXFFST == 0)

{

for (i=4;i<8;i++)
       {
           I2caRegs.I2CDXR=(unsigned int)SndData[i]; /*FIFO*/
       }

}

Thanks and best regards

Andrej

C2000™︎ microcontrollers

C2000 microcontrollers forum

TMS320F28062: I2C repeat mode