Posts: 36
Joined: Tue Sep 04, 2012 9:36 pm

I2c problems

Tue Jan 22, 2013 6:40 pm

I have a DS1339AU+ RTC connected to my pi and i2cdetect was detecting it. I finally found a driver that works with this chip and was able to read and write to it twice. I've rebooted the system since then and now i2cdetect no longer finds this device. All the i2c mods are loaded and there is power to the RTC module(verified with MM).

Any ideas what may be going on? I've also tried a new chip on the RTC module and i2cdetect doesn't find that either.

I have a couple of 1wire devices connected and running and I can access all of those but they are not running on the I2c bus.

Is it possible the I2c bus got fried? There are no pullups on the RTC module so I know that is not the problem.

Is there away to reset the bus?
Does the bus always use the pullups or can they be turned on and off through software?

Also I do have the PIs pins protected with a 330ohm resisters and 3.3v zenner diodes even though the DS1339AU+ should not pose a problem since it runs off of 3.3V and not 5V like the DS1307.

Any help would be greatly appreciated!

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