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When using I2C sensors, we almost always have to run a cable from the RoboRIO to the sensor itself. Sometimes there's a problem with the wiring. This page has some techniques for testing and troubleshooting i2c wiring.
The RoboRIO i2c connector looks like this:
It has four pins:
- common or ground
- 3.3v power or running the sensor
- SCL, “serial clock”
- SDA, “serial data”
Grab the multimeter
To see if the i2c port is alive, and getting properly conveyed to the other end of a cable, one can grab a multimeter. If the cable can be removed and tested seperately, do that first using the “ohms” or “continuity” function. Be sure to check for shorts between wires as well as continuity of each wire from end to end.
We can also test the far end of i2c cable, to see if we can “see” the RoboRIO through the cable.