Abstract: An apparatus and method for expansion of an inter-IC (I2C) is provided. An expansion processor resides on a primary I2C bus. The expansion processor is coupled to a plurality of I2C sub-buses each of which may host a plurality of I2C devices. Data is transferred between the expansion processor and the plurality of I2C devices via the corresponding sub-bus according to an I2C protocol. Data transfer is in response to a request initiated by a bus master on the primary I2C bus. The bus master communicates with a target device residing on one of the sub-buses by addressing the expansion processor. The bus master informs the expansion processor of the target device by sending the expansion processor a number of the sub-bus on which the target device resides, and an address of the target device. A data stream bound for the target device is directed to the expansion processor which the echos it to the target device.

Abstract: A vital product data (VPD) detection circuit mountable on a substrate of a pluggable component. The circuit comprises a "parallel read" circuit for generating vital product data associated with the pluggable component, a "serial read" circuit for storing and retrieving vital product data associated with the pluggable component, and means for interconnecting the parallel and serial read circuits. The parallel read circuit preferably comprises a parallel array of transistors surface-mounted on the substrate, and the serial read circuit preferably comprises a serial EEPROM having a clock input, a set of address inputs, and a bidirectional data pin. A VPD detection mechanism may disable the parallel VPD circuitry in favor of the serial VPD detection circuitry, or vice versa, or these circuits may be enabled but activated in a mutually exclusive manner.