I'm using an I2C interface for my e-compass and controller. The capacitance of the e-compass I2C pin is 20pF, and that of the I2C controller is approximately 40pF.
But the problem is: I want to use a 100cm long wire, but don't know how to measure wire capacitance, and there is a PMDC motor which injects noise into the line.
The question is how to ensure my I2C capacitance is not exceeded,
and what I2C buffer I need to use (any specfic IC?).