4 replies to this topic

[Zoot]

I'm hoping that someone can help...

 

I'm making a small weather logger, using a humidity sensor, real time clock, barometer and a temperature sensor all built on an Arduino shield, fitted with an SD card.

 

The problem that I'm having is that the RTC (DS1307) and the barometer chip (BM085) both use I2C.  I've searched the forum for a way to have these two items share the I2C bus, but haven't found anything.  I'm not sure it's even possible.  Would a better solution be to hardware multiplex with an external logic chip?

 

I'd much rather do it in code if I can due to limited space on the shield.  Any ideas?

[Frode]

Hi Zoot, I2C is intended for having multiple devices connected to the same bus, so this doesn't sound like something that should be a problem unless the devices have the same I2C address. Do they?

[Zoot]

AFAIK, the devices don't have the same address.  I'm a little new to I2C.  Are there any tutorials that you can recommend so that I can get a better understanding of it? 

[Frode]

This forum post is probably a good startingpoint.

[Zoot]

Thanks for the link.  Just what I was looking for.