[TriEmbed] Basic I2C Question

[Charles McClelland]

First, I wanted to thank Paul for the excellent presentation on interrupts.  I now have a Watch Dog Timer routine which is saving me from having to put a clock on one project.  

On my other project though, I still need a clock.  And since I am already using an I2C bus, I thought I could simply add one to that bus.  That way I will have two I2C sensors connected to an Arduino (ATMEGA328).  My question is how to best implement the pull-up the resistors.  Should I put resistors on each (perhaps 10k since they will effectively be in parallel) or should I put one set of pull up resistors on the main board for both?  It seems like the latter is the better approach but I did not know if there was some reason to do one over the other.   

On a related note, I need a 3.3V I2C Real Time Clock with Alarms - I am looking at the DS1339 and hoping I can use some of the DS1307 library since they are both from Maxim.  Any other suggestions?

Thanks,

Chip