[En-Nut-Discussion] I2C questions

[Kowalsky, Richard]

Hello All,

    I have a custom Mega128 based board and am using Enut 3.9.8. My
board has 2 - Max5821 I2C DAC's and 2 - Dallas DS1803 Digital
Potentiometers.  I have read the data sheets and the 128 manual but
still have some questions. I am trying to control them but have not had
any success yet.  The Mega128 will be the master.    If anyone can help,
I would really appreciate it.

    I know I need to call TwInit(addr) first to initialize the I2C bus,
but I am confused about the <addr> argument.  Can I just use any unused
address value?

    Next, I think I need to call TwIOCtl() to set the bus speed, but I
noticed that TwInit() already calls TwIOCtl() once so I am not sure if
this is really necessary.  If I do call TwIOCtl() and I want to run the
I2C buss at 100Khz, do I just literally pass 100,000 as the argument?

    Lastly, once I call TwInit() and TwIOCtl(), is that it?  From then
on, I just call TwMasterTransact() as needed?

    Sorry for the many questions, I think I am close but must be missing
one thing here or there.

    If anyone is willing to share any sample code, I would appreciate it
very much, if not, no problem.

Thanks in advance,
Richard




       

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