Abstract: A method and apparatus is disclosed for reducing ringing of a digital signal delivered over a transmission line. A clamping circuit implemented in accordance with one embodiment of the invention includes a delay circuit. The delay circuit receives an input signal delivered over a transmission line and delivers a second signal after a preselected delay. A driver circuit receives the second signal and the input signal and provides an enable signal to a transistor for a period of time corresponding to the preselected delay. The transistor is coupled between a supply voltage and the transmission line. An inverter having an input and an output is also included, with the input of the inverter electrically connected to the transmission line. An additional transistor is electrically coupled between the supply voltage and the transmission line.

Abstract: An apparatus for arbitrating ownership of an interface between two hub agents is described. The apparatus includes a data path input/output unit to communicate with a data path and an arbitration circuit. The arbitration unit includes a least recently serviced status tracking circuit to determine which of the data path input/output unit and a device that transmits the second request signal has been granted ownership of the data path least recently, an arbitration signal output circuit to output a first request signal, and an arbitration signal input circuit to receive a second request signal. The arbitration unit grants ownership of the data path to the data path input/output unit when the first request signal is asserted if the second request signal is not asserted.

Abstract: One embodiment of a graphics device that can be disabled when an upgrade graphics device is installed is described. The graphics device includes an interface to a bus and an input to receive a device disable signal. When the device disable signal is asserted, the interface to the bus places its buffers in a high impedance state, meaning that the graphics device is electrically isolated from the bus. When the device disable signal transitions from asserted to deasserted, a reset circuit in the graphics device resets the graphics device.