It looks like you have some extra capacitance on the bus. There should not be any capacitors bridging the I2C data and clock lines. Some of the third-party universal interface cards have extra capacitance, so take those off.
I have never heard of an I2C part with built in pull-up resistors. Do to the multi-drop nature of the I2C bus, pull up resistors are almost always external. There are some "weak pull up" resistors you could turn on in the BBB, but are too high in value for most applications. I suggest you read up on how to select pull up resistors for an I2C bus. Phillips (now NXP) initially developed the bus and has good documentation. Google: NXP I2C bus documentation But the short answer is that for a 3.3V bus, resistors in the range of 1.2K to 3.3K should work fine. The value is not critical. You want to pull 1 to 3 mA through the resistor when the bus is low. --- Graham == -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/a8ed3ca6-d286-4d29-8dc1-8851aa384db3%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
