Echo reduction on bit-serial, multi-drop bus
AssigneeIntel Corporation
InventorEric C. Hannah
Life of this patent
Estimating the term…
Abstract
Methods of active echo reduction on a multi-drop bus utilizing devices of dynamically-variable impedance, wherein non-signaling intermediate devices are placed in a high-impedance state while all remaining devices are matched to the characteristic impedance of the multi-drop bus. Devices of dynamically-variable impedance capable of implementing methods of active echo reduction on a multi-drop bus are included, as well as systems incorporating such devices.
Claims15
A method of active echo reduction on a multi-drop bus having a plurality of input/output devices, comprising:
- determining which of the plurality of input/output devices are intermediate devices;
- determining which of the plurality of input/output devices are in a non-signaling status;
- and
- adjusting an impedance of an input/output device to a high-impedance state when the input/output device is an intermediate device in a non-signaling status.
A method of active echo reduction on a multi-drop bus having a plurality of input/output devices, comprising:
- determining a status and a type of each of the plurality of input/output devices, wherein the status of each of the plurality of input/output devices is selected from the group consisting of signaling and non-signaling, further wherein the type of each of the plurality of input/output devices is selected from the group consisting of intermediate device and end-point device;
- matching an impedance of each end-point device and each signaling device to a characteristic impedance of the multi-drop bus;
- and
- placing each non-signaling intermediate device in a high-impedance state.
A method of active echo reduction on a multi-drop bus having a master device and at least two slave devices, comprising:
- determining which of the at least two slave devices is a signaling device, wherein all remaining slave devices are non-signaling devices;
- determining a type of each at least two slave devices, wherein the type is selected from the group consisting of intermediate device and end-point device;
- adjusting an impedance of the signaling device to approximately half of a characteristic impedance of the multi-drop bus when the signaling device is an intermediate device;
- adjusting an impedance of each end-point device to approximately equal to the characteristic impedance of the multi-drop bus;
- and
- placing each non-signaling intermediate device in a high-impedance state.
A system, comprising:
- a processor;
- a multi-drop bus coupled to the processor;
- and
- a plurality of input/output devices coupled to the multi-drop bus, wherein each of the plurality of input/output devices comprises:
- an input/output port suitable for coupling to a multi-drop bus;
- and
- an input/output driver circuit having an impedance and coupled to the input/output port, wherein the input/output driver circuit selectively adjusts its impedance to a high-impedance state when the input/output device is a non-signaling intermediate device.
An input/output device, comprising:
- an input/output port suitable for coupling to a multi-drop bus;
- and
- an input/output driver circuit having an impedance and coupled to the input/output port, wherein the input/output driver circuit is adapted to selectively adjust its impedance to a high-impedance state when the input/output device is a non-signaling intermediate device.
A method of reducing reflections from an input/output device coupled to a multi-drop bus at an intermediate location, the method comprising:
- determining a status of the input/output device, wherein the status is selected from the group consisting of signaling and non-signaling;
- and
- adjusting an impedance of the input/output device to a high-impedance state when the input/output device is in a non-signaling status.
Dependencies are inferred from the claim text.