Patent ID: 7259584

Claim:
A gating circuit associated with impedance control signals applied to a bus driver circuit, the gating circuit comprising: sensing logic for sensing a need to change an impedance control signal to be applied to the bus driver circuit wherein the bus is a PCI bus and wherein the driver circuit is a PCI bus driver circuit; and gating logic coupled to the sensing logic for updating the impedance control signal to the driver circuit only when the bus associated with the bus driver circuit is either in a PCI bus Idle state or is in a PCI bus Parked state, wherein the gating logic includes: logic to allow updating of the impedance control signal to the PCI bus driver circuit only when the PCI bus driver circuit is not presently driving a PCI IRDY bus signal and is not presently driving a PCI FRAME bus signal and is not presently driving a PCI DEVSEL bus signal and is not presently driving a PCI REQ bus signal.