Patent ID: 7111102

Claim:
A method of selectively determining an operating frequency for a SPI-4 bus of a host computer system that uses a port adapter, wherein the operating frequency may be different than a conventional SPI-4 bus operating frequency, the method comprising the steps of: issuing a query from a host computer system having a SPI-4 bus to a port adapter, the port adapter comprising a SPI-4 bus that can be coupled to a host system for control and data between the host and the SPI-4 device, a control bus coupled in parallel with the SPI-4 bus between the host system and the port adapter, and interface logic that interfaces the SPI-4 bus and the control bus to one of a plurality of line interfaces, and an identification repository; receiving, from the identification repository, an identification of the port adapter; determining, based on the information received from the identification repository, whether the host system SPI-4 bus can operate at a frequency that is compatible with at least one of the SPI-4 bus operating frequencies that are supported by the port adapter; and setting an operating frequency of the host system SPI-4 bus equal to a selected one of the SPI-4 bus operating frequencies that are supported by the port adapter; further comprising powering-on the port adapter only when the host system SPI-4 bus can operate at a frequency that is compatible with at least one of the SPI-4 bus operating frequencies that are supported by the port adapter.