Design of a Highly Reliable Controller for an I2C Bus

The design of a highly reliable controller for a digital data bus incorporates improvements, in both hardware and software, over the basic design of a low-speed, low-power, serial bus known in the industry as "I2C." ("I2C" signifies "inter integrated circuit bus" — a bus developed by Philips Semiconductors in the early 1980s.) The original design of the I2C bus lacks fault-tolerant features that could protect against bit errors, shorting of output drives, or babbling nodes (nodes that misbehave or disrupt normal communication). The present design adds such features: It augments the standard I2C bus protocol with low-overhead error-detection features and a fail-silent messaging system, and it adds hardware features that automatically isolate babbling nodes. These fault-tolerant features can be disabled through software (for example, to aid testing), but the design makes it difficult to do this accidentally.