Patent ID: 7472033

Claim:
An apparatus comprising: functional components of circuitry defined on a semiconductor chip that supply output signals from said semiconductor chip to another semiconductor chip that interfaces with said semiconductor chip, the functional components including a component that has modifiable operating characteristics that affect interface characteristics of the output signals, a performance measuring circuit providing an output indicative of operating characteristics of the functional components of circuitry defined on the semiconductor chip during operation of the functional components of circuitry wherein said performance measuring circuit comprises a plurality of ring oscillators, and computer implemented software means for controlling via a register a value provided to the component having modifiable operating characteristics that affect the interface characteristics of the output signals in response to an output provided by the performance measuring circuit, wherein said controlling a value comprises selecting clock delays that are managed so that the timing of data transfer made with respect to a clock signal is controlled wherein at least one of said plurality of ring oscillators is selected based on said value that is provided to said register from said computer-implemented software means.