This is accomplished by transparently converting the I2C clock and data lines to multi-drop differential busses. This removes the limitations on distance, speed, and number of nodes of an I2C bus and takes advantage of the noise immunity of differential signaling. In addition to the differential signals, two pairs of wires in the ethernet cables can be used to supply power to all the nodes, eliminating the need for a power supply at each node. Using the extenders, a bus needs two End Nodes and may contain Series Nodes. See the example application wiring diagrams for more information.

The I2C Extender works by separating the SCL (clock) and SDA (data) lines of a I2C bus into two sets of transmit and receive lines. These lines control CAN transceivers, creating two CAN-like busses – one bus for the I2C clock and another for the data. Note that this is not a true CAN bus that you can connect other CAN devices to. The conversion to CAN and back is transparent so no special hardware or software is required on the I2C side of the nodes.

Features:

• Works with any I2C logic levels, making it possible to have different logic level devices on the same bus
• Supports multi-master mode
• Tested to 365ft at 100kHz and 165ft at 400kHz
• Allows for up to 42 nodes
• Allows for bus speeds up to 1MHz
• Allows the use of multiple I2C devices at each node