High performance repeater
First Claim
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1. An apparatus comprising:
- a redriver device to receive signals from a first device on first pins of the redriver and forward the signals on second pins of the redriver to a second device on a differential link, wherein the redriver device comprises an AC-coupled redriver and each of the first and second devices comprise DC-coupled devices;
detection circuitry to detect presence of the second device on the link, wherein detecting the presence of the second device comprises detecting a pulldown voltage on the second pins generated from termination of the second device on the link; and
pulldown relay circuitry to generate an emulated version of the pulldown voltage of the second device on the first pins using a voltage source of the redriver device in response to detecting presence of the second device on the link, wherein the emulated version of the pulldown voltage identifies the presence of the second device on the link to the first device,wherein the emulated version of the pulldown voltage is generated with characteristics defined in a interconnect protocol to cause the first device to transition from a receiver detect state defined in a link state machine of the interconnect protocol to a transmitting link state defined in the link state machine, and the redriver device is to detect signaling within the active link state and disable the pulldown relay circuitry to allow the redriver device to forward the signals from the first device to the second device during the transmitting link state.
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Abstract
A redriver device is provided to receive signals from a first device and forward the signals to a second device on a differential link. Detection circuitry is provided to detect presence of the second device on the link by detecting a pulldown voltage generated from termination of the second device on the link, and pulldown relay circuitry is provided to generate an emulated version of the pulldown voltage of the second device on pins to connect to the first device in response to detecting presence of the second device on the link.
11 Citations
24 Claims
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1. An apparatus comprising:
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a redriver device to receive signals from a first device on first pins of the redriver and forward the signals on second pins of the redriver to a second device on a differential link, wherein the redriver device comprises an AC-coupled redriver and each of the first and second devices comprise DC-coupled devices; detection circuitry to detect presence of the second device on the link, wherein detecting the presence of the second device comprises detecting a pulldown voltage on the second pins generated from termination of the second device on the link; and pulldown relay circuitry to generate an emulated version of the pulldown voltage of the second device on the first pins using a voltage source of the redriver device in response to detecting presence of the second device on the link, wherein the emulated version of the pulldown voltage identifies the presence of the second device on the link to the first device, wherein the emulated version of the pulldown voltage is generated with characteristics defined in a interconnect protocol to cause the first device to transition from a receiver detect state defined in a link state machine of the interconnect protocol to a transmitting link state defined in the link state machine, and the redriver device is to detect signaling within the active link state and disable the pulldown relay circuitry to allow the redriver device to forward the signals from the first device to the second device during the transmitting link state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An apparatus comprising:
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AC-coupled redriver circuitry to; receive, at input pins, signals from a first endpoint device on a link, amplify the received signals, and forward the amplified signals on output pins to a second endpoint device on the link, wherein each of the first and second devices comprise DC-coupled devices; detection circuitry to detect a DC pulldown voltage on the output pins corresponding to termination of the second endpoint device on the link; and pulldown relay circuitry to generate an emulated pulldown voltage corresponding to a receiver detection state in response to detection of an instance of the pulldown voltage, wherein the pulldown voltage is generated on the input pins to be detected by the first endpoint device within the receiver detection state, wherein the pulldown voltage emulates the DC pulldown voltage to identify the termination of the second endpoint device on the link to the first endpoint device, wherein the emulated version of the pulldown voltage is generated with characteristics defined in a interconnect protocol to cause the first device to transition from a detect state defined in a link state machine of the interconnect protocol to a transmitting link state defined in the link state machine, and the redriver device is to detect signaling within the active link state and disable the pulldown relay circuitry to allow the redriver device to forward the signals from the first device to the second device during the transmitting link state.
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20. A system comprising:
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a DC-coupled first device; and an AC-coupled redriver connected to the first device on a differential link, the redriver comprising; first pins to connect to the DC-coupled first device on the link; second pins to connect to a second device on the link; detection circuitry to detect termination of the second device on-the link, wherein the detection circuitry detects a pulldown voltage on the second pins generated by the termination of the second device; and pulldown relay circuitry to generate an emulated version of the pulldown voltage on the first pins, in response to detection of the pulldown voltage, for presentation to the first device on the link, wherein the emulated version of the pulldown voltage comprises a DC voltage identifiable by the first device to determine that the second device is present, the emulated version of the pulldown voltage is generated with characteristics defined in a interconnect protocol to cause the first device to transition from a detect state defined in a link state machine of the interconnect protocol to a transmitting link state defined in the link state machine, and the redriver device is to detect signaling within the active link state and disable the pulldown relay circuitry to allow the redriver device to forward the signals from the first device to the second device during the transmitting link state. - View Dependent Claims (21, 22, 23, 24)
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Specification