Analog Devices,inc.

Linear Technology Holding LLC

Jason J Ziomek

Eric C Gaalaas

Brian Kirk Jadus

Bikiran Goswami

Dongwan Ha

Methods and apparatus are disclosed for communicating multiple logic states across a digital isolator. The digital isolator is a universal serial bus (USB) isolator in some embodiments. The digital isolator includes one or more single-bit data channels. Three or more logic states of information are transmitted across the single-bit data channel(s). The logic states are distinguished by a pulse sequence, and in particular a number of edges of the pulse sequence and a final value or final edge of the pulse sequence.

Coding schemes for communicating multiple logic states through a digital isolator

A first circuit board includes a master device and slave devices communicating with each other via a local first I2C bus. To allow I2C networks to communicate with each other over long distances, such as up to 1200 meters, a first interface device converts the I2C data signals to encoded differential data over a twisted wire pair. A second interface device on a remote circuit board converts the differential data to data and clock signals on its local second I2C bus coupled to other slave devices on the same board. This is equivalent to the two boards sharing the same I2C bus. The interface devices pull down the serial clock line (SCL) in their local I2C bus while waiting for data, such as an acknowledge bit. The master device generates the clock signal for its local I2C bus, and the remote interface device generates the clock signal for its local I2C bus.

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South Burlington, VT, United States of America

Jason J Ziomek