US20210311898A1 - Adjustable embedded universal serial bus 2 low-impedance driving duration - Google Patents
Adjustable embedded universal serial bus 2 low-impedance driving duration Download PDFInfo
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- US20210311898A1 US20210311898A1 US17/347,882 US202117347882A US2021311898A1 US 20210311898 A1 US20210311898 A1 US 20210311898A1 US 202117347882 A US202117347882 A US 202117347882A US 2021311898 A1 US2021311898 A1 US 2021311898A1
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- Y02D10/00—Energy efficient computing, e.g. low power processors, power management or thermal management
Definitions
- the system includes an embedded Universal Serial Bus 2 (eUSB2) device having a first receiver and a first transmitter, a processor, a second transmitter coupled to the processor, a second receiver coupled to the processor, a drive low circuit coupled to the processor second transmitter, and differential signal lines having a length greater than ten inches.
- the differential signal lines are coupled at a first end to the first receiver and the first transmitter and at a second end to the second transmitter and the second receiver.
- the processor is configured to control the drive low circuit to drive the differential signal lines low with a logic ‘0’ to cause the first receiver to receive the logic ‘0’ and a value of a signal present on the differential signal lines to reach about 0 volts.
- the method includes transmitting an end of packet (EOP) indicator via differential signal lines, after transmitting the EOP indicator, driving the differential signal lines low for a period of 4 unit intervals plus a value of a propagation delay existing on the differential signal lines, and after driving the differential signal lines low for the period of 4 unit intervals plus the value of the propagation delay existing on the differential signal lines, placing the differential signal lines in a high-impedance (high-z) state.
- EOP end of packet
- the circuit includes an amplifier having a first output coupled to a first node and a second output coupled to a second node.
- the circuit further includes a first resistor coupled between the second node and a ground terminal and a second resistor coupled between the first node and the ground terminal.
- the circuit further includes a third resistor, a fourth resistor, a first switch coupled to the first resistor, and a second switch coupled to the second resistor.
- FIG. 1 shows a block diagram of an illustrative system in accordance with various examples
- FIG. 2A shows a schematic diagram of an illustrative circuit in accordance with various examples
- FIG. 2B shows a schematic diagram of an illustrative circuit in accordance with various examples
- FIG. 3 shows a diagram of illustrative waveforms in accordance with various examples
- FIG. 4 shows a diagram of illustrative waveforms in accordance with various examples.
- FIG. 5 shows a flowchart of an illustrative method in accordance with various examples.
- USB Universal Serial Bus
- USB refers to any version of the USB specification, including any amendments or supplements, certified by the USB Implementers Forum (USB IF) or any suitable body who replaces and/or aids the USB IF in its role overseeing the USB specification, whether now existing or later developed.
- USB as referred to herein, encompasses any one or more of the USB 1.0 specification, USB 2.0 specification, USB 3.0 specification, USB 4.0 specification, or any derivatives thereof, such as amended or “.x” variations of the above specifications.
- legacy USB refers to USB 2.x and/or USB 1.x.
- Embedded USB (eUSB) in at least some examples, refers to eUSB2.
- USB was primarily intended for implementation in specifying standards for connection and communication between personal computers and peripheral devices.
- adoption of the USB standard has expanded and implementation in computing devices of support for the USB standard has gained in popularity, efforts have been made to extend and expand the applicability of USB.
- USB has expanded to communication between peripheral devices, between personal computers, and other use cases.
- SoC system-on-a-chip
- Such implementations are sometimes referred to as eUSB2.
- an eUSB2 repeater operates as a bridge or non-linear re-driver between eUSB2 and legacy USB systems, or vice versa, to translate between legacy USB signaling voltage levels that are customarily about 3.3 volts (V) and eUSB2 signaling voltages levels that are circuit-level (e.g., silicon appropriate voltages) such as about 1.0 V, 1.2 V, 1.4 V, or any other suitable value less than 3.3 V.
- V 3.3 volts
- the eUSB2 specification requires a transmitter (or a circuit coupled to an output of the transmitter) to drive the differential signal lines low (e.g., couple each of the differential input signals to a ground potential through an about 40 ohm, or other comparatively small value, resistor) for a maximum of 4 unit intervals (UIs), where a unit interval is the period of time for transmitting 1 bit of data.
- driving the differential signals low is synonymous with driving the differential signal lines with a logic ‘0’ through a low resistance path.
- Driving the each of the differential signal lines low is intended to clear each of the signal lines of any data or voltage remaining on either of the differential signal lines.
- a weak pull-down is activated to place the differential signal lines in a high-impedance (e.g., high-z) state, enabling, in some examples, single-ended communication via either of the differential signal lines or a receiving device to then begin transmitting over the differential signal lines.
- the high-impedance state is defined as, in some examples, coupling each of the differential signal lines to the ground potential (e.g., driving the differential signal lines with a logic ‘0’) through an about 7 kiloohm, or other comparatively large value, resistor or resistance path.
- the differential signal lines may transition to the high-impedance state prior to a full length of the differential signal lines being driven low. Accordingly, in at least some examples it is desirable to modify the drive-low protocol of an eUSB2 system to cause a drive low circuit in the eUSB2 system to drive differential signal lines low for an extended duration of time exceeding existing eUSB2 specification of driving with a low impedance for 4 UI while not inhibiting an ability of a receiving device to then begin transmitting on the differential signal lines.
- the circuit in at least some examples, includes an eUSB2 transmitter and a drive low circuit.
- the circuit is an eUSB2 repeater suitable for use in interfacing between eUSB2 and USB interfaces.
- the circuit in at least some examples, provides for the transmission of data via a transmitter via eUSB2 protocols and/or specification.
- the data is transmitted, in some examples, via differential signal lines.
- the circuit drives the differential signal lines low.
- the circuit drives the differential signal lines low by coupling each of the differential signal lines to a ground potential through a resistor having a resistance of less than about 100 ohms (e.g., such as an about 40 ohm resistor).
- the circuit drives the differential signal lines low, in some examples, to clear the differential signal lines of any residual voltage, current, charge, or other remnant of the data previously transmitted via the differential signal lines.
- the circuit drives the differential signal lines low for about 4 UI plus a propagation delay associated with the differential signal lines.
- the propagation delay of the differential signal lines is determined, such as through testing, tuning, verification, or any other suitable process. Based on the determined propagation delay, the circuit drives the differential signal lines low for a sufficient period of time for the low signal to reach an end of the differential signal lines. After driving the differential signal lines low, the circuit places the differential signal lines in a weak pull-down state, coupling each of the differential signal lines to the ground potential through a resistor having a comparatively large resistance when compared to the resistor used in driving the differential signal lines low (e.g., such as a resistor having a resistance of about 7 kiloohms).
- a receiving device is able to begin transmitting over the differential signal lines 4 UI after receiving the EOP indicator because of the circuit placing the differential signal lines in the weak-pull down state for 4 UI plus the propagation delay of the differential signal lines after transmitting the EOP indicator.
- Driving the differential signal lines low for the extended period of time in at least some examples, provides for the low driven signal to reach an end of the differential signal lines despite the propagation delay of the differential signal lines.
- the system 100 is illustrative of a computing device, or elements of a computing device.
- the system 100 includes a processor 105 , an eUSB2 device 110 , an eUSB2 repeater 115 , and a USB device 120 .
- the processor 105 includes, or is coupled to, a transmitter (TX) 125 , a receiver (RX) 140 , and a drive-low circuit 150
- the eUSB2 repeater 115 includes a TX 130 and a RX 135 .
- the USB device 120 is a legacy USB device, as described elsewhere herein.
- one or both of the eUSB2 device 110 or the USB device 120 is implemented external to the system 100 and configured to couple to the system 100 through an appropriate interface (e.g., such as a port and receptacle suitable for performing communication according to eUSB2 or USB protocol, respectively.
- the processor 105 is, in some examples, a SoC.
- the eUSB2 device 110 is any device operating in both ingress and egress communication directions according to signal voltage level specifications for eUSB2.
- the USB device 120 is any device operating in both ingress and egress communication directions according to signal voltage level specifications for legacy USB.
- the USB device 120 is a peripheral such as a user input device, (e.g., a sensor, a scanner, an imaging device, a microphone, etc.), an output device (e.g., a printer, speakers, etc.), a storage device, or any other peripheral, component, or device suitable for communicating with the processor 105 .
- a user input device e.g., a sensor, a scanner, an imaging device, a microphone, etc.
- an output device e.g., a printer, speakers, etc.
- storage device e.g., a storage device suitable for communicating with the processor 105 .
- the eUSB2 repeater 115 communicatively couples the processor 105 to the USB device 120 and vice versa, converting signals appropriate for the processor 105 to signals appropriate for the USB device 120 and vice versa.
- signaling in the processor 105 is performed in a range of about 0.8 V to about 1.4 V.
- signaling in the USB device 120 is performed at about 3.3 V or about 5 V.
- the eUSB2 repeater 115 operates as a bit-level repeater, receiving signals from one of the processor 105 or USB device 120 and converting the signals for use by the other of the processor 105 or USB device 120 (e.g., by shifting a voltage level of the signals upward or downward based on a direction of the communications).
- differential data communicated in the system 100 begins with a start of packet (SOP) indicator and ends with an EOP indicator.
- SOP start of packet
- the TX 125 transmits data according to eUSB2 protocols or standards via differential signal lines 145 that is received by the RX 135 and the TX 130 transmits data according to eUSB2 protocols or standards via the differential signal lines 145 that is received by the RX 140 .
- the TX 130 is permitted to begin transmitting data via the differential signal lines 145 .
- the differential signal lines 145 have a length sufficient to create a propagation delay between the TX 125 and the RX 135 of 1 UI or greater.
- the RX 135 When the propagation delay between the TX 125 and the RX 135 is 1 UI or greater and the drive low circuit 150 drives the differential signal lines 145 low for 4 UI and then subsequently places the differential signal lines 145 in a high-z state, the RX 135 , in some examples, does not see the differential signal lines 145 being driven low for the full 4 UI and energy remains on the differential signal lines 145 . Instead, in at least some examples, the RX 135 sees the differential signal lines 145 driven low for less than about 4 UI. Accordingly, the TX 130 does not become aware that the differential signal lines 145 are available for transmission to the RX 140 .
- the processor 105 has prior knowledge of a propagation delay of the differential signal lines 145 and/or the processor 105 determines a propagation delay of the differential signal lines 145 according to any suitable known signaling technique for determining delay.
- the processor 105 Based on the known or determined propagation delay, the processor 105 increases a duration of time that the drive low circuit 150 drives the differential signal lines 145 with a logic ‘0’ after the TX 125 transmits an EOP indicator. For example, when the propagation delay of the differential signal lines 145 is about X UI, where X is a non-negative integer number (e.g., 0, 1, 2, . . . ), the processor 105 controls the drive low circuit 150 to drive the differential signal lines 145 , after transmitting an EOP indicator, with a logic ‘0’ for about a period of about (Y+X) UI, where Y is a value in a range of [1,4]. In at least some examples, as used herein for ease of description, Y has a value of 4.
- the processor 105 controls the drive low circuit 150 to place the differential signal lines 145 in a high-z state, for example, controlling the drive low circuit 150 to couple each of the differential signal lines to the ground potential through a path that includes about 7 kiloohms of resistance.
- driving the differential signal lines 145 with the logic ‘0’ for about (4+X) UI exceeds an amount of time permitted by existing eUSB2 standards (e.g., of drive-low for 4 UI).
- existing eUSB2 standards e.g., of drive-low for 4 UI.
- the RX 135 first receives the EOP indicator with a propagation delay of X UI and the TX 130 then waits 4 UI before attempting to transmit, when the TX 130 begins transmitting 4 UI after receipt of the EOP indicator, the differential signal lines have been released from the drive-low state and the system remains in compliance with eUSB2 standards from the perspective of the RX 135 and TX 130 .
- the differential signal lines 145 of greater than 10 inches in length are fully-driven low despite the propagation delay of X UI and without inhibiting operation of the RX 135 and/or TX 130 .
- the TX 130 begins transmitting data beginning with an SOP indicator to the processor 105 via the RX 140 .
- a processor (not shown) of the eUSB2 repeater 115 controls the TX 130 , or a drive low circuit (not shown) of the eUSB2 repeater 115 , to drive the differential signals with a logic ‘0” for about (4+X) UI and place the differential signal lines 145 in the high-z state in substantially the same manner as discussed above with respect to the TX 125 .
- FIGS. 2A and 2B a schematic diagram of a circuit 200 is shown.
- the circuit 200 is suitable for implementation as the drive-low circuit 150 of the system 100 of FIG. 1 .
- the circuit 200 is electrically positioned in series between an output of a transmitter (e.g., such as an amplifier) in an eUSB2 and terminals at which the transmitter couples to differential signaling lines to transmit a differential signal.
- a transmitter e.g., such as an amplifier
- the circuit 200 includes a resistor 202 , a resistor 204 , a resistor 206 , a resistor 208 , a switch 210 , and a switch 212 .
- the resistor 202 is coupled between a node 214 and ground terminal 216
- the resistor 204 is coupled between a node 218 and the ground terminal 216
- the resistor 206 is coupled between a node 220 and the ground terminal 216
- the resistor 208 is coupled between a node 222 and the ground terminal 216 .
- the switch 210 is coupled between the node 218 and the node 222 and the switch 212 is coupled between the node 214 and the node 220 .
- the circuit 200 is configured to couple to a differential amplifier 224 (e.g., such as an amplifier operational as a transmitter) at the node 214 and the node 218 in series with transmission lines (e.g., as represented as the node 220 and the node 220 ) coupled to the differential amplifier 224 .
- the differential amplifier 224 is, in some examples, an eUSB2 transmitter, controllable to output a signal, or not output the signal, based on a received control signal CTRL.
- the node 220 and the node 222 are, in at least some examples, terminals of a differential signal line in an eUSB2 system (e.g., eD ⁇ and eD+ terminals, respectively).
- the switch 210 and the switch 212 are each any component suitable for, or capable of, switching a signal between the node 218 and the node 222 and between the node 214 and the node 220 , respectively, based on a control signal EN.
- the switch 210 and the switch 212 are each implemented as respective transistors.
- the resistor 202 is coupled between a node 222 and the ground terminal 216 via the switch 210
- the resistor 204 is coupled between a node 220 and the ground terminal 216 via the switch 212
- the resistor 206 is coupled between the node 222 and the ground terminal 216
- the resistor 208 is coupled between the node 220 and the ground terminal 216 .
- the circuit 200 is configured to couple to a differential amplifier 224 (e.g., such as an amplifier operational as a transmitter) at the node 222 and the node 220 in parallel with transmission lines (e.g., as represented as the node 222 and the node 220 ) coupled to the differential amplifier 224 .
- the differential amplifier 224 is, in some examples, an eUSB2 transmitter, controllable to output a signal, or not output the signal, based on a received control signal CTRL.
- the node 222 and the node 220 in at least some examples, terminals of a differential signal line in an eUSB2 system (e.g., eD ⁇ and eD+ terminals, respectively).
- the switch 210 and the switch 212 are each any component suitable for, or capable of, switching a signal between the resistor 202 and the ground terminal 216 and between the resistor 204 and the ground terminal 216 , respectively, based on a control signal EN.
- the switch 210 and the switch 212 are each implemented as respective transistors.
- the switches 210 and 212 are controlled via EN to control a pull-down strength present at the node 222 and the node 220 , respectively.
- EN has a logical low value
- the switch 210 and the switch 212 are each in an open state.
- a pull-down strength present at the node 222 is determined according to a resistance of the resistor 206 and a pull-down strength present at the node 220 is determined according to a resistance of the resistor 208 .
- EN has a logical high value
- the switch 210 and the switch 212 are each in a closed state.
- the pull-down strength present at the node 222 is determined according to the resistance of the resistor 206 in parallel combination with a resistance of the resistor 202 (and any additional resistance added by the switch 210 ) and the pull-down strength present at the node 220 is determined according to a resistance of the resistor 208 in parallel combination with a resistance of the resistor 204 (and any additional resistance added by the switch 212 ).
- the resistor 202 and the resistor 204 each have a resistance of about 40 ohms and the resistor 206 and the resistor 208 each have a resistance of about 7 kiloohms.
- a pull-down strength present at the node 222 and a pull-down strength present at the node 220 can be dynamically controlled by the switch 210 and the switch 212 , respectively, based on a value of EN to provide a strong pull-down or a weak pull-down at the node 222 and the node 220 .
- the diagram 300 includes a waveform 302 and a waveform 304 .
- the waveform 302 is representative of signals present on the differential signal lines 145 of the system 100 of FIG. 1 when a propagation delay exists on the differential signal lines 145 and the differential signal lines 145 are not driven low for greater than 4 UI after transmission of an EOP indicator.
- the waveform 304 is representative of signals present on the differential signal lines 145 when a propagation delay exists on the differential signal lines 145 and the differential signal lines 145 are driven low after transmission of an EOP indicator for a period of 4 UI plus the duration of the propagation delay.
- a line state of the differential signal lines 145 (e.g., a voltage present on the differential signal lines 145 ) remains elevated, not going low because the logic ‘0’ driven from one end of the differential signal lines 145 does not reach the other end of the differential signal lines 145 because of the propagation delay.
- a line state of the differential signal lines 145 goes low within about 4 UI resulting from the extended duration that the differential signal lines 145 are driven low by a drive low circuit.
- the diagram 400 includes a waveform 402 , a waveform 404 , and a waveform 406 .
- the waveform 402 is representative of a control signal for controlling the driving low of differential signal lines in a system that does not extend the driving time to compensate for a propagation delay of the differential signal lines.
- the waveform 402 corresponds to a same system as the waveform 302 of the diagram 300 of FIG. 3 in which the duration of driving the differential signal lines is not extended and therefore the differential signal lines are prevented from going low because of the propagation delay of the differential signal lines.
- the waveform 404 is representative of a control signal for controlling the driving low of differential signal lines in a system that extends the driving time to compensate for the propagation delay of the differential signal lines.
- the waveform 404 corresponds to a same system as the waveform 304 of the diagram 300 in which the duration of driving the differential signal lines is extended and therefore the differential signal lines are fully driven low despite the propagation delay of the differential signal lines.
- the waveform 404 is a signal as would be generated by the processor 105 for controlling the drive-low circuit 150 (e.g., such as for controlling one or more switches that couple the differential signal lines to a ground potential through a resistor or a path having a resistance of about 40 ohms).
- the waveform 406 is a signal as would be generated by the processor 105 for controlling the TX 125 (e.g., an enable signal for the TX 125 ).
- the duration of time between time t 1 and time t 2 illustrated in FIG. 4 corresponds to the known or determined propagation delay of the differential signal lines, and therefore a duration by which the driving low of the differential signal lines is extended.
- the method 500 corresponds to actions performed by one or more components of the system 100 of FIG. 1 .
- the method 500 is, in some examples, a method for controlling a drive low circuit, such as a drive low circuit coupled to a transmitter in an eUSB2 system.
- the control is exerted, in various examples, by any suitable component having processing capabilities such as a processor, a microprocessor, a logic circuit, etc.
- Implementation of the method 500 by a circuit is advantageous in ensuring that differential signal lines in the eUSB2 system are fully driven low despite the transmitter driving the differential signal lines low for a period of time longer than permitted by eUSB2 protocols or standards.
- a transmitter is controlled to transmit an EOP indicator via differential signal lines.
- the EOP indicator is, in various examples, a series of static value bits having a length defined and/or limited by eUSB2 standards.
- the EOP indicator in some examples, follows transmission of differential data via the differential signal lines.
- a circuit is controlled to drive the differential signal lines low by driving the differential signal lines with a logic ‘0’.
- the circuit drives the differential signal lines low by coupling the differential signal lines to a ground potential through a resistor or path having a resistance of about 40 ohms.
- the circuit is controlled to drive the differential signal lines low for a period of about (4+X) UI, where X is a non-negative integer representative of a propagation delay of the differential signal lines resulting at least partially from a length of the differential signal lines.
- X is 0 and the circuit is controlled to drive the differential signal lines low for a period of about 4 UI. However, when X is non-zero, the circuit is controlled to drive the differential signal lines low for greater than 4 UI. In at least some examples, driving the differential signal lines low after transmission of an EOP indicator for greater than 4 UI is contrary to eUSB2 standards and, in some examples, has a potential to cause incompatibility across eUSB2 devices.
- the circuit is controlled to place the differential signal lines in a high-z state.
- the circuit places the differential signal lines in the high-z state, in at least some examples, by coupling the differential signal lines to the ground potential through a resistor or path having a resistance of about 7 kiloohms.
- the circuit is controlled to place the differential signal lines in the high-z state after the circuit has driven the differential signal lines low for about (4+X) UI.
- the driving low of the differential signal lines is within the limits set forth by the eUSB2 standards.
- the differential signal lines include a propagation delay of X UI and the circuit drove the differential signal lines low at the operation 510 for about (4+X) UI prior to placing the differential signal lines in the high-z state at operation 515 , the receiver only sees ((4+X) ⁇ X) UI, or simply 4 UI, worth of driven low logic ‘0’ before the differential signal lines are placed in the high-z state. Therefore, from the perspective of the receiver, the transmission remains within eUSB2 standards and communication continues unaffected by the driving low of the differential signal lines for about (4+X) UI.
- the method 500 includes additional operations that are not recited herein (e.g., such as intermediary comparisons, logical operations, output selections such as via a multiplexer, etc.), in some examples any one or more of the operations recited herein include one or more sub-operations (e.g., such as intermediary comparisons, logical operations, output selections such as via a multiplexer, etc.), in some examples any one or more of the operations recited herein is omitted, and/or in some examples any one or more of the operations recited herein is performed in an order other than that presented herein (e.g., in a reverse order, substantially simultaneously, overlapping, etc.), all of which is intended to fall within the scope of the present disclosure.
- additional operations that are not recited herein (e.g., such as intermediary comparisons, logical operations, output selections such as via a multiplexer, etc.)
- any one or more of the operations recited herein include one or more sub-operations (e
- the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .”
- the term “couple” or “couples” is intended to mean either an indirect or direct wired or wireless connection.
- a first device, element, or component couples to a second device, element, or component, that coupling may be through a direct coupling or through an indirect coupling via other devices, elements, or components and connections.
- a device, element, or component that is coupled between a first component or location and a second component or location may be through a direct connection or through an indirect connection via other devices, elements, or components and/or couplings.
- a device that is “configured to” perform a task or function may be configured (e.g., programmed and/or hardwired) at a time of manufacturing by a manufacturer to perform the function and/or may be configurable (or re-configurable) by a user after manufacturing to perform the function and/or other additional or alternative functions.
- the configuring may be through firmware and/or software programming of the device, through a construction and/or layout of hardware components and interconnections of the device, or a combination thereof.
- a circuit or device that is said to include certain components may instead be configured to couple to those components to form the described circuitry or device.
- a structure described as including one or more semiconductor elements such as transistors), one or more passive elements (such as resistors, capacitors, and/or inductors), and/or one or more sources (such as voltage and/or current sources) may instead include only the semiconductor elements within a single physical device (e.g., a semiconductor die and/or integrated circuit (IC) package) and may be configured to couple to at least some of the passive elements and/or the sources to form the described structure either at a time of manufacture or after a time of manufacture, for example, by an end-user and/or a third-party.
- semiconductor elements such as transistors
- passive elements such as resistors, capacitors, and/or inductors
- sources such as voltage and/or current sources
- While certain components are described herein as being of a particular process technology (e.g., FET, metal oxide semiconductor FET (MOSFET), n-type, p-type, drain-extended, natural, etc.), these components may be exchanged for components of other process technologies (e.g., replace FET and/or MOSFET with bi-polar junction transistor (BJT), replace n-type with p-type or vice versa, etc.) and reconfiguring circuits including the replaced components to provide desired functionality at least partially similar to functionality available prior to the component replacement.
- Components illustrated as resistors are generally representative of any one or more elements coupled in series and/or parallel to provide an amount of impedance represented by the illustrated resistor.
- ground voltage potential in the foregoing discussion are intended to include a chassis ground, an Earth ground, a floating ground, a virtual ground, a digital ground, a common ground, and/or any other form of ground connection applicable to, or suitable for, the teachings of the present disclosure. Unless otherwise stated, “about”, “approximately”, or “substantially” preceding a value means+/ ⁇ 10 percent of the stated value.
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Abstract
Description
- This divisional application claims priority to U.S. patent application Ser. No. 16/414,496, filed May 16, 2019, which claims priority to U.S. Provisional Patent Application No. 62/764,940, filed Aug. 16, 2018, both of which are incorporated herein by reference in their entirety.
- Aspects of the present disclosure provide for a system. In at least some examples, the system includes an embedded Universal Serial Bus 2 (eUSB2) device having a first receiver and a first transmitter, a processor, a second transmitter coupled to the processor, a second receiver coupled to the processor, a drive low circuit coupled to the processor second transmitter, and differential signal lines having a length greater than ten inches. The differential signal lines are coupled at a first end to the first receiver and the first transmitter and at a second end to the second transmitter and the second receiver. The processor is configured to control the drive low circuit to drive the differential signal lines low with a logic ‘0’ to cause the first receiver to receive the logic ‘0’ and a value of a signal present on the differential signal lines to reach about 0 volts.
- Other aspects of the present disclosure provide for a method. In at least some examples, the method includes transmitting an end of packet (EOP) indicator via differential signal lines, after transmitting the EOP indicator, driving the differential signal lines low for a period of 4 unit intervals plus a value of a propagation delay existing on the differential signal lines, and after driving the differential signal lines low for the period of 4 unit intervals plus the value of the propagation delay existing on the differential signal lines, placing the differential signal lines in a high-impedance (high-z) state.
- Other aspects of the present disclosure provide for a circuit. In at least some examples, the circuit includes an amplifier having a first output coupled to a first node and a second output coupled to a second node. The circuit further includes a first resistor coupled between the second node and a ground terminal and a second resistor coupled between the first node and the ground terminal. The circuit further includes a third resistor, a fourth resistor, a first switch coupled to the first resistor, and a second switch coupled to the second resistor.
- For a detailed description of various examples, reference will now be made to the accompanying drawings in which:
-
FIG. 1 shows a block diagram of an illustrative system in accordance with various examples; -
FIG. 2A shows a schematic diagram of an illustrative circuit in accordance with various examples; -
FIG. 2B shows a schematic diagram of an illustrative circuit in accordance with various examples; -
FIG. 3 shows a diagram of illustrative waveforms in accordance with various examples; -
FIG. 4 shows a diagram of illustrative waveforms in accordance with various examples; and -
FIG. 5 shows a flowchart of an illustrative method in accordance with various examples. - Universal Serial Bus (USB) is a standard establishing specifications for interconnect cabling, connectors, and communication protocols. As referred to herein, USB refers to any version of the USB specification, including any amendments or supplements, certified by the USB Implementers Forum (USB IF) or any suitable body who replaces and/or aids the USB IF in its role overseeing the USB specification, whether now existing or later developed. In at least one example, USB, as referred to herein, encompasses any one or more of the USB 1.0 specification, USB 2.0 specification, USB 3.0 specification, USB 4.0 specification, or any derivatives thereof, such as amended or “.x” variations of the above specifications. Also, as referred to herein, legacy USB refers to USB 2.x and/or USB 1.x. Embedded USB (eUSB), in at least some examples, refers to eUSB2.
- At its inception, USB was primarily intended for implementation in specifying standards for connection and communication between personal computers and peripheral devices. However, as adoption of the USB standard has expanded and implementation in computing devices of support for the USB standard has gained in popularity, efforts have been made to extend and expand the applicability of USB. For example, while initially establishing specifications for communications between personal computers and peripheral devices, USB has expanded to communication between peripheral devices, between personal computers, and other use cases. As a result of such widespread implementation and use of USB, efforts are being further made to utilize USB as a communication protocol among individual subsystems or circuits (e.g., such as a system-on-a-chip (SoC)). Such implementations are sometimes referred to as eUSB2. New challenges arise in implementing eUSB2. For example, at a circuit level, computing devices often operate at voltage levels that vary from those of conventional USB, creating an impediment between direct communication between eUSB2 and legacy USB systems. To mitigate this impediment, an eUSB2 repeater operates as a bridge or non-linear re-driver between eUSB2 and legacy USB systems, or vice versa, to translate between legacy USB signaling voltage levels that are customarily about 3.3 volts (V) and eUSB2 signaling voltages levels that are circuit-level (e.g., silicon appropriate voltages) such as about 1.0 V, 1.2 V, 1.4 V, or any other suitable value less than 3.3 V.
- After a final bit of an end of packet (EOP) indicator of communication in an eUSB2 system is transmitted via differential signal lines, in at least some examples the eUSB2 specification requires a transmitter (or a circuit coupled to an output of the transmitter) to drive the differential signal lines low (e.g., couple each of the differential input signals to a ground potential through an about 40 ohm, or other comparatively small value, resistor) for a maximum of 4 unit intervals (UIs), where a unit interval is the period of time for transmitting 1 bit of data. In at least some examples, driving the differential signals low is synonymous with driving the differential signal lines with a logic ‘0’ through a low resistance path. Driving the each of the differential signal lines low, in at least some examples, is intended to clear each of the signal lines of any data or voltage remaining on either of the differential signal lines. After the differential signal lines are driven low, a weak pull-down is activated to place the differential signal lines in a high-impedance (e.g., high-z) state, enabling, in some examples, single-ended communication via either of the differential signal lines or a receiving device to then begin transmitting over the differential signal lines. The high-impedance state is defined as, in some examples, coupling each of the differential signal lines to the ground potential (e.g., driving the differential signal lines with a logic ‘0’) through an about 7 kiloohm, or other comparatively large value, resistor or resistance path. However, when a physical length of the differential signal lines is sufficient to cause a propagation delay of 1 UI or greater to exist on either of the differential signal lines, the differential signal lines may transition to the high-impedance state prior to a full length of the differential signal lines being driven low. Accordingly, in at least some examples it is desirable to modify the drive-low protocol of an eUSB2 system to cause a drive low circuit in the eUSB2 system to drive differential signal lines low for an extended duration of time exceeding existing eUSB2 specification of driving with a low impedance for 4 UI while not inhibiting an ability of a receiving device to then begin transmitting on the differential signal lines.
- At least some aspects of the present disclosure provide for a circuit. The circuit, in at least some examples, includes an eUSB2 transmitter and a drive low circuit. In some examples, the circuit is an eUSB2 repeater suitable for use in interfacing between eUSB2 and USB interfaces. The circuit, in at least some examples, provides for the transmission of data via a transmitter via eUSB2 protocols and/or specification. The data is transmitted, in some examples, via differential signal lines. In at least some examples, after a final transition of an EOP indicator of the data (e.g., either a falling edge or a rising edge indicating an end of the EOP indicator and therefore an end of transmission of the data), the circuit drives the differential signal lines low. In at least some examples, the circuit drives the differential signal lines low by coupling each of the differential signal lines to a ground potential through a resistor having a resistance of less than about 100 ohms (e.g., such as an about 40 ohm resistor). The circuit drives the differential signal lines low, in some examples, to clear the differential signal lines of any residual voltage, current, charge, or other remnant of the data previously transmitted via the differential signal lines. In at least some examples, the circuit drives the differential signal lines low for about 4 UI plus a propagation delay associated with the differential signal lines. For example, at a time of manufacture of the circuit and/or a system including both the circuit and the differential signal lines, the propagation delay of the differential signal lines is determined, such as through testing, tuning, verification, or any other suitable process. Based on the determined propagation delay, the circuit drives the differential signal lines low for a sufficient period of time for the low signal to reach an end of the differential signal lines. After driving the differential signal lines low, the circuit places the differential signal lines in a weak pull-down state, coupling each of the differential signal lines to the ground potential through a resistor having a comparatively large resistance when compared to the resistor used in driving the differential signal lines low (e.g., such as a resistor having a resistance of about 7 kiloohms). It at least some examples, despite the circuit driving the differential signal lines low for an extended period of time approximately equal to 4 UI plus the propagation delay of the differential signal lines, a receiving device is able to begin transmitting over the differential signal lines 4 UI after receiving the EOP indicator because of the circuit placing the differential signal lines in the weak-pull down state for 4 UI plus the propagation delay of the differential signal lines after transmitting the EOP indicator. Driving the differential signal lines low for the extended period of time, in at least some examples, provides for the low driven signal to reach an end of the differential signal lines despite the propagation delay of the differential signal lines.
- Turning now to
FIG. 1 , a block diagram of anillustrative system 100 is shown. In at least some examples, thesystem 100 is illustrative of a computing device, or elements of a computing device. For example, thesystem 100 includes aprocessor 105, aneUSB2 device 110, aneUSB2 repeater 115, and aUSB device 120. In at least some examples, theprocessor 105 includes, or is coupled to, a transmitter (TX) 125, a receiver (RX) 140, and a drive-low circuit 150, and theeUSB2 repeater 115 includes aTX 130 and aRX 135. TheUSB device 120 is a legacy USB device, as described elsewhere herein. In some examples, one or both of theeUSB2 device 110 or theUSB device 120 is implemented external to thesystem 100 and configured to couple to thesystem 100 through an appropriate interface (e.g., such as a port and receptacle suitable for performing communication according to eUSB2 or USB protocol, respectively. Theprocessor 105 is, in some examples, a SoC. TheeUSB2 device 110 is any device operating in both ingress and egress communication directions according to signal voltage level specifications for eUSB2. TheUSB device 120 is any device operating in both ingress and egress communication directions according to signal voltage level specifications for legacy USB. For example, in at least some implementations theUSB device 120 is a peripheral such as a user input device, (e.g., a sensor, a scanner, an imaging device, a microphone, etc.), an output device (e.g., a printer, speakers, etc.), a storage device, or any other peripheral, component, or device suitable for communicating with theprocessor 105. - The
eUSB2 repeater 115 communicatively couples theprocessor 105 to theUSB device 120 and vice versa, converting signals appropriate for theprocessor 105 to signals appropriate for theUSB device 120 and vice versa. For example, in some implementations signaling in theprocessor 105 is performed in a range of about 0.8 V to about 1.4 V. Similarly, in some implementations signaling in theUSB device 120 is performed at about 3.3 V or about 5 V. In at least some examples, theeUSB2 repeater 115 operates as a bit-level repeater, receiving signals from one of theprocessor 105 orUSB device 120 and converting the signals for use by the other of theprocessor 105 or USB device 120 (e.g., by shifting a voltage level of the signals upward or downward based on a direction of the communications). In some examples, differential data communicated in thesystem 100 begins with a start of packet (SOP) indicator and ends with an EOP indicator. - In at least some examples, the
TX 125 transmits data according to eUSB2 protocols or standards viadifferential signal lines 145 that is received by theRX 135 and theTX 130 transmits data according to eUSB2 protocols or standards via thedifferential signal lines 145 that is received by theRX 140. For example, after theRX 135 receives an EOP indicator from theTX 125 and the differential signal lines are driven low (as seen at the RX 135) for 4 UI by the drivelow circuit 150, theTX 130 is permitted to begin transmitting data via the differential signal lines 145. In at least some examples, thedifferential signal lines 145 have a length sufficient to create a propagation delay between theTX 125 and theRX 135 of 1 UI or greater. When the propagation delay between theTX 125 and theRX 135 is 1 UI or greater and the drivelow circuit 150 drives thedifferential signal lines 145 low for 4 UI and then subsequently places thedifferential signal lines 145 in a high-z state, theRX 135, in some examples, does not see thedifferential signal lines 145 being driven low for the full 4 UI and energy remains on the differential signal lines 145. Instead, in at least some examples, theRX 135 sees thedifferential signal lines 145 driven low for less than about 4 UI. Accordingly, theTX 130 does not become aware that thedifferential signal lines 145 are available for transmission to theRX 140. For example, in at least some implementations of thesystem 100 in which thedifferential signal lines 145 have a length greater than about 10 inches, driving thedifferential signal lines 145 low (e.g., driving the differential signal lines with a logic ‘0’) for 4 UI is insufficient to fully propagate the logic ‘0’ to theRX 135. In at least some examples, theprocessor 105 has prior knowledge of a propagation delay of thedifferential signal lines 145 and/or theprocessor 105 determines a propagation delay of thedifferential signal lines 145 according to any suitable known signaling technique for determining delay. Based on the known or determined propagation delay, theprocessor 105 increases a duration of time that the drivelow circuit 150 drives thedifferential signal lines 145 with a logic ‘0’ after theTX 125 transmits an EOP indicator. For example, when the propagation delay of thedifferential signal lines 145 is about X UI, where X is a non-negative integer number (e.g., 0, 1, 2, . . . ), theprocessor 105 controls the drivelow circuit 150 to drive thedifferential signal lines 145, after transmitting an EOP indicator, with a logic ‘0’ for about a period of about (Y+X) UI, where Y is a value in a range of [1,4]. In at least some examples, as used herein for ease of description, Y has a value of 4. In at least some examples, after controlling the drivelow circuit 150 to drive a logic ‘0’ for about (4+X) UI, theprocessor 105 controls the drivelow circuit 150 to place thedifferential signal lines 145 in a high-z state, for example, controlling the drivelow circuit 150 to couple each of the differential signal lines to the ground potential through a path that includes about 7 kiloohms of resistance. - In at least some examples, driving the
differential signal lines 145 with the logic ‘0’ for about (4+X) UI exceeds an amount of time permitted by existing eUSB2 standards (e.g., of drive-low for 4 UI). However, because theRX 135 first receives the EOP indicator with a propagation delay of X UI and theTX 130 then waits 4 UI before attempting to transmit, when theTX 130 begins transmitting 4 UI after receipt of the EOP indicator, the differential signal lines have been released from the drive-low state and the system remains in compliance with eUSB2 standards from the perspective of theRX 135 andTX 130. In this way, thedifferential signal lines 145 of greater than 10 inches in length are fully-driven low despite the propagation delay of X UI and without inhibiting operation of theRX 135 and/orTX 130. - In at least some examples, after the drive
low circuit 150 drives thedifferential signal lines 145 with the logic ‘0’ for (4+X) UI and places thedifferential signal lines 145 in the high-z state, theTX 130 begins transmitting data beginning with an SOP indicator to theprocessor 105 via theRX 140. After theTX 130 transmits an EOP indicator to theRX 140, a processor (not shown) of theeUSB2 repeater 115 controls theTX 130, or a drive low circuit (not shown) of theeUSB2 repeater 115, to drive the differential signals with a logic ‘0” for about (4+X) UI and place thedifferential signal lines 145 in the high-z state in substantially the same manner as discussed above with respect to theTX 125. - Turning now to
FIGS. 2A and 2B , a schematic diagram of acircuit 200 is shown. In at least some examples, thecircuit 200 is suitable for implementation as the drive-low circuit 150 of thesystem 100 ofFIG. 1 . For example, in at least some implementations thecircuit 200 is electrically positioned in series between an output of a transmitter (e.g., such as an amplifier) in an eUSB2 and terminals at which the transmitter couples to differential signaling lines to transmit a differential signal. - In at least some examples, the
circuit 200 includes aresistor 202, aresistor 204, aresistor 206, aresistor 208, aswitch 210, and aswitch 212. In at least one example architecture, as illustrated byFIG. 2A , theresistor 202 is coupled between anode 214 andground terminal 216, theresistor 204 is coupled between anode 218 and theground terminal 216, theresistor 206 is coupled between anode 220 and theground terminal 216, and theresistor 208 is coupled between anode 222 and theground terminal 216. Theswitch 210 is coupled between thenode 218 and thenode 222 and theswitch 212 is coupled between thenode 214 and thenode 220. In at least some examples, thecircuit 200 is configured to couple to a differential amplifier 224 (e.g., such as an amplifier operational as a transmitter) at thenode 214 and thenode 218 in series with transmission lines (e.g., as represented as thenode 220 and the node 220) coupled to thedifferential amplifier 224. Thedifferential amplifier 224 is, in some examples, an eUSB2 transmitter, controllable to output a signal, or not output the signal, based on a received control signal CTRL. Thenode 220 and thenode 222 are, in at least some examples, terminals of a differential signal line in an eUSB2 system (e.g., eD− and eD+ terminals, respectively). Theswitch 210 and theswitch 212, in at least some examples, are each any component suitable for, or capable of, switching a signal between thenode 218 and thenode 222 and between thenode 214 and thenode 220, respectively, based on a control signal EN. In at least some examples, theswitch 210 and theswitch 212 are each implemented as respective transistors. - Alternatively, in at least one example architecture, as illustrated by
FIG. 2B , theresistor 202 is coupled between anode 222 and theground terminal 216 via theswitch 210, theresistor 204 is coupled between anode 220 and theground terminal 216 via theswitch 212, theresistor 206 is coupled between thenode 222 and theground terminal 216, and theresistor 208 is coupled between thenode 220 and theground terminal 216. In at least some examples, thecircuit 200 is configured to couple to a differential amplifier 224 (e.g., such as an amplifier operational as a transmitter) at thenode 222 and thenode 220 in parallel with transmission lines (e.g., as represented as thenode 222 and the node 220) coupled to thedifferential amplifier 224. Thedifferential amplifier 224 is, in some examples, an eUSB2 transmitter, controllable to output a signal, or not output the signal, based on a received control signal CTRL. Thenode 222 and thenode 220, in at least some examples, terminals of a differential signal line in an eUSB2 system (e.g., eD− and eD+ terminals, respectively). Theswitch 210 and theswitch 212, in at least some examples, are each any component suitable for, or capable of, switching a signal between theresistor 202 and theground terminal 216 and between theresistor 204 and theground terminal 216, respectively, based on a control signal EN. In at least some examples, theswitch 210 and theswitch 212 are each implemented as respective transistors. - In at least some examples of operation of the
circuit 200, theswitches node 222 and thenode 220, respectively. For example, when EN has a logical low value, theswitch 210 and theswitch 212 are each in an open state. When theswitch 210 and theswitch 212 are each in the open state, a pull-down strength present at thenode 222 is determined according to a resistance of theresistor 206 and a pull-down strength present at thenode 220 is determined according to a resistance of theresistor 208. When EN has a logical high value, theswitch 210 and theswitch 212 are each in a closed state. When theswitch 210 and theswitch 212 are each in the closed state, the pull-down strength present at thenode 222 is determined according to the resistance of theresistor 206 in parallel combination with a resistance of the resistor 202 (and any additional resistance added by the switch 210) and the pull-down strength present at thenode 220 is determined according to a resistance of theresistor 208 in parallel combination with a resistance of the resistor 204 (and any additional resistance added by the switch 212). In at least some examples, theresistor 202 and theresistor 204 each have a resistance of about 40 ohms and theresistor 206 and theresistor 208 each have a resistance of about 7 kiloohms. In this way, a pull-down strength present at thenode 222 and a pull-down strength present at thenode 220 can be dynamically controlled by theswitch 210 and theswitch 212, respectively, based on a value of EN to provide a strong pull-down or a weak pull-down at thenode 222 and thenode 220. - Turning now to
FIG. 3 , a diagram 300 of illustrative waveforms is shown. In at least some examples, the diagram 300 includes awaveform 302 and awaveform 304. Thewaveform 302 is representative of signals present on thedifferential signal lines 145 of thesystem 100 ofFIG. 1 when a propagation delay exists on thedifferential signal lines 145 and thedifferential signal lines 145 are not driven low for greater than 4 UI after transmission of an EOP indicator. Thewaveform 304 is representative of signals present on thedifferential signal lines 145 when a propagation delay exists on thedifferential signal lines 145 and thedifferential signal lines 145 are driven low after transmission of an EOP indicator for a period of 4 UI plus the duration of the propagation delay. - As shown by the
waveform 302, after completion of transmission of the EOP indicator at a time t1, a line state of the differential signal lines 145 (e.g., a voltage present on the differential signal lines 145) remains elevated, not going low because the logic ‘0’ driven from one end of thedifferential signal lines 145 does not reach the other end of thedifferential signal lines 145 because of the propagation delay. As shown by thewaveform 304, after completion of transmission of the EOP indicator at a time t2, a line state of thedifferential signal lines 145 goes low within about 4 UI resulting from the extended duration that thedifferential signal lines 145 are driven low by a drive low circuit. - Turning now to
FIG. 4 , a diagram 400 of illustrative waveforms is shown. In at least some examples, the diagram 400 includes awaveform 402, awaveform 404, and awaveform 406. Thewaveform 402 is representative of a control signal for controlling the driving low of differential signal lines in a system that does not extend the driving time to compensate for a propagation delay of the differential signal lines. In at least one example, thewaveform 402 corresponds to a same system as thewaveform 302 of the diagram 300 ofFIG. 3 in which the duration of driving the differential signal lines is not extended and therefore the differential signal lines are prevented from going low because of the propagation delay of the differential signal lines. Thewaveform 404 is representative of a control signal for controlling the driving low of differential signal lines in a system that extends the driving time to compensate for the propagation delay of the differential signal lines. In at least one example, thewaveform 404 corresponds to a same system as thewaveform 304 of the diagram 300 in which the duration of driving the differential signal lines is extended and therefore the differential signal lines are fully driven low despite the propagation delay of the differential signal lines. For example, thewaveform 404 is a signal as would be generated by theprocessor 105 for controlling the drive-low circuit 150 (e.g., such as for controlling one or more switches that couple the differential signal lines to a ground potential through a resistor or a path having a resistance of about 40 ohms). In at least some examples, thewaveform 406 is a signal as would be generated by theprocessor 105 for controlling the TX 125 (e.g., an enable signal for the TX 125). In at least some examples, the duration of time between time t1 and time t2 illustrated inFIG. 4 corresponds to the known or determined propagation delay of the differential signal lines, and therefore a duration by which the driving low of the differential signal lines is extended. - Turning now to
FIG. 5 , a flowchart of anillustrative method 500 is shown. In at least some examples, themethod 500 corresponds to actions performed by one or more components of thesystem 100 ofFIG. 1 . Themethod 500 is, in some examples, a method for controlling a drive low circuit, such as a drive low circuit coupled to a transmitter in an eUSB2 system. The control is exerted, in various examples, by any suitable component having processing capabilities such as a processor, a microprocessor, a logic circuit, etc. Implementation of themethod 500 by a circuit, in at least some examples, is advantageous in ensuring that differential signal lines in the eUSB2 system are fully driven low despite the transmitter driving the differential signal lines low for a period of time longer than permitted by eUSB2 protocols or standards. - At
operation 505, a transmitter is controlled to transmit an EOP indicator via differential signal lines. The EOP indicator is, in various examples, a series of static value bits having a length defined and/or limited by eUSB2 standards. The EOP indicator, in some examples, follows transmission of differential data via the differential signal lines. - At
operation 510, a circuit is controlled to drive the differential signal lines low by driving the differential signal lines with a logic ‘0’. In at least some examples, the circuit drives the differential signal lines low by coupling the differential signal lines to a ground potential through a resistor or path having a resistance of about 40 ohms. The circuit is controlled to drive the differential signal lines low for a period of about (4+X) UI, where X is a non-negative integer representative of a propagation delay of the differential signal lines resulting at least partially from a length of the differential signal lines. When the differential signal lines are less than about 10 inches in length, or the differential signal lines otherwise do not have a propagation delay of at least 1 UI, X is 0 and the circuit is controlled to drive the differential signal lines low for a period of about 4 UI. However, when X is non-zero, the circuit is controlled to drive the differential signal lines low for greater than 4 UI. In at least some examples, driving the differential signal lines low after transmission of an EOP indicator for greater than 4 UI is contrary to eUSB2 standards and, in some examples, has a potential to cause incompatibility across eUSB2 devices. - At
operation 515, the circuit is controlled to place the differential signal lines in a high-z state. The circuit places the differential signal lines in the high-z state, in at least some examples, by coupling the differential signal lines to the ground potential through a resistor or path having a resistance of about 7 kiloohms. In at least some examples, the circuit is controlled to place the differential signal lines in the high-z state after the circuit has driven the differential signal lines low for about (4+X) UI. Despite driving the differential signal lines low for a period of time longer than permitted by eUSB2 standards, in at least some examples from a perspective of a receiver located on an opposite end of the differential signal lines from the transmitter and the circuit, the driving low of the differential signal lines is within the limits set forth by the eUSB2 standards. For example, because the differential signal lines include a propagation delay of X UI and the circuit drove the differential signal lines low at theoperation 510 for about (4+X) UI prior to placing the differential signal lines in the high-z state atoperation 515, the receiver only sees ((4+X)−X) UI, or simply 4 UI, worth of driven low logic ‘0’ before the differential signal lines are placed in the high-z state. Therefore, from the perspective of the receiver, the transmission remains within eUSB2 standards and communication continues unaffected by the driving low of the differential signal lines for about (4+X) UI. - While the operations of the
method 500 have been discussed and labeled with numerical reference, in various examples themethod 500 includes additional operations that are not recited herein (e.g., such as intermediary comparisons, logical operations, output selections such as via a multiplexer, etc.), in some examples any one or more of the operations recited herein include one or more sub-operations (e.g., such as intermediary comparisons, logical operations, output selections such as via a multiplexer, etc.), in some examples any one or more of the operations recited herein is omitted, and/or in some examples any one or more of the operations recited herein is performed in an order other than that presented herein (e.g., in a reverse order, substantially simultaneously, overlapping, etc.), all of which is intended to fall within the scope of the present disclosure. - In the foregoing discussion, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct wired or wireless connection. Thus, if a first device, element, or component couples to a second device, element, or component, that coupling may be through a direct coupling or through an indirect coupling via other devices, elements, or components and connections. Similarly, a device, element, or component that is coupled between a first component or location and a second component or location may be through a direct connection or through an indirect connection via other devices, elements, or components and/or couplings. A device that is “configured to” perform a task or function may be configured (e.g., programmed and/or hardwired) at a time of manufacturing by a manufacturer to perform the function and/or may be configurable (or re-configurable) by a user after manufacturing to perform the function and/or other additional or alternative functions. The configuring may be through firmware and/or software programming of the device, through a construction and/or layout of hardware components and interconnections of the device, or a combination thereof. Furthermore, a circuit or device that is said to include certain components may instead be configured to couple to those components to form the described circuitry or device. For example, a structure described as including one or more semiconductor elements (such as transistors), one or more passive elements (such as resistors, capacitors, and/or inductors), and/or one or more sources (such as voltage and/or current sources) may instead include only the semiconductor elements within a single physical device (e.g., a semiconductor die and/or integrated circuit (IC) package) and may be configured to couple to at least some of the passive elements and/or the sources to form the described structure either at a time of manufacture or after a time of manufacture, for example, by an end-user and/or a third-party.
- While certain components are described herein as being of a particular process technology (e.g., FET, metal oxide semiconductor FET (MOSFET), n-type, p-type, drain-extended, natural, etc.), these components may be exchanged for components of other process technologies (e.g., replace FET and/or MOSFET with bi-polar junction transistor (BJT), replace n-type with p-type or vice versa, etc.) and reconfiguring circuits including the replaced components to provide desired functionality at least partially similar to functionality available prior to the component replacement. Components illustrated as resistors, unless otherwise stated, are generally representative of any one or more elements coupled in series and/or parallel to provide an amount of impedance represented by the illustrated resistor. Additionally, uses of the phrase “ground voltage potential” in the foregoing discussion are intended to include a chassis ground, an Earth ground, a floating ground, a virtual ground, a digital ground, a common ground, and/or any other form of ground connection applicable to, or suitable for, the teachings of the present disclosure. Unless otherwise stated, “about”, “approximately”, or “substantially” preceding a value means+/−10 percent of the stated value.
- The above discussion is meant to be illustrative of the principles and various examples of the present disclosure. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the present disclosure be interpreted to embrace all such variations and modifications.
Claims (5)
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US17/347,882 US20210311898A1 (en) | 2018-08-16 | 2021-06-15 | Adjustable embedded universal serial bus 2 low-impedance driving duration |
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US201862764940P | 2018-08-16 | 2018-08-16 | |
US16/414,496 US11068428B2 (en) | 2018-08-16 | 2019-05-16 | Adjustable embedded universal serial bus 2 low-impedance driving duration |
US17/347,882 US20210311898A1 (en) | 2018-08-16 | 2021-06-15 | Adjustable embedded universal serial bus 2 low-impedance driving duration |
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US16/414,496 Division US11068428B2 (en) | 2018-08-16 | 2019-05-16 | Adjustable embedded universal serial bus 2 low-impedance driving duration |
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Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170344508A1 (en) * | 2016-05-26 | 2017-11-30 | Silicon Laboratories Inc. | System, USB Type-C Connector And Method To Transmit Encoded Data |
US20180173670A1 (en) * | 2016-12-20 | 2018-06-21 | Huawei Technologies Co., Ltd. | Drive circuit and driving method for serial communications system |
US10156590B1 (en) * | 2015-10-09 | 2018-12-18 | American Innovations, Ltd. | Digital multimeter |
Family Cites Families (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19756942C2 (en) | 1997-12-22 | 1999-10-07 | Heidelberger Druckmasch Ag | Printing press cylinders, in particular impression cylinders for a sheet-fed rotary printing press |
KR100272671B1 (en) | 1998-03-09 | 2000-11-15 | 윤종용 | Bidirectional transceiver and bus interface with the same |
CN1220943C (en) * | 2001-11-07 | 2005-09-28 | 旺玖科技股份有限公司 | Universal serial bus (USB) connection detecting circuit system and its operation method |
US7461192B2 (en) | 2004-12-15 | 2008-12-02 | Rambus Inc. | Interface for bridging out-of-band information and preventing false presence detection of terminating devices |
JP4414974B2 (en) * | 2006-02-28 | 2010-02-17 | パナソニック株式会社 | Data receiver |
ITMI20071104A1 (en) | 2007-05-31 | 2008-12-01 | St Microelectronics Srl | "CONTROL DEVICE FOR A USB INTERFACE AND ITS CONTROL METHOD" |
US7808277B2 (en) * | 2008-09-18 | 2010-10-05 | Hewlett-Packard Development Company, L.P. | Bidirectional signal separation module for a bus converter |
US8432182B2 (en) * | 2009-03-30 | 2013-04-30 | Analog Devices, Inc. | USB isolator with advanced control features |
US8683097B2 (en) * | 2012-06-30 | 2014-03-25 | Intel Corporation | Device connect detection |
US9239810B2 (en) * | 2012-06-30 | 2016-01-19 | Intel Corporation | Low power universal serial bus |
US8982746B2 (en) * | 2012-06-30 | 2015-03-17 | Intel Corporation | Clock-less half-duplex repeater |
US8872546B2 (en) * | 2012-09-13 | 2014-10-28 | Intel Corporation | Interface circuitry for a test apparatus |
US20140244889A1 (en) * | 2013-02-27 | 2014-08-28 | Wilocity Ltd. | Pci-e reference clock passive splitter and method thereof |
US9537479B2 (en) * | 2013-12-16 | 2017-01-03 | Intel Corporation | Programmable impedance transmitter for serial communication |
US9606955B2 (en) * | 2014-02-10 | 2017-03-28 | Intel Corporation | Embedded universal serial bus solutions |
US9836420B2 (en) * | 2014-12-09 | 2017-12-05 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Integrated systems with universal serial Bus 2.0 and embedded universal serial Bus 2 connectivity |
US9596749B2 (en) * | 2014-12-11 | 2017-03-14 | Intel Corporation | Circuit board having a signal layer with signal traces and a reference plane with an additional signal trace larger than the signal traces |
US10084698B2 (en) * | 2015-03-26 | 2018-09-25 | Intel Corporation | Selectively enabling first and second communication paths using a repeater |
US9843436B2 (en) * | 2015-06-27 | 2017-12-12 | Intel Corporation | Flexible interconnect architecture |
US20180173666A1 (en) * | 2016-12-16 | 2018-06-21 | Intel Corporation | APPARATUSES AND METHODS TO COUPLE AN EMBEDDED UNIVERSAL SERIAL BUS (eUSB) CIRCUIT TO A UNIVERSAL SERIAL BUS (USB) TRANSCEIVER INTERFACE CIRCUIT |
US10366041B2 (en) * | 2017-01-27 | 2019-07-30 | Micron Technology, Inc. | Methods and apparatuses for differential signal termination |
-
2019
- 2019-05-16 US US16/414,496 patent/US11068428B2/en active Active
- 2019-08-14 CN CN201980067967.2A patent/CN112867996B/en active Active
- 2019-08-14 WO PCT/US2019/046564 patent/WO2020037075A1/en unknown
- 2019-08-14 EP EP19849942.8A patent/EP3837612A4/en active Pending
-
2021
- 2021-06-15 US US17/347,882 patent/US20210311898A1/en active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10156590B1 (en) * | 2015-10-09 | 2018-12-18 | American Innovations, Ltd. | Digital multimeter |
US20170344508A1 (en) * | 2016-05-26 | 2017-11-30 | Silicon Laboratories Inc. | System, USB Type-C Connector And Method To Transmit Encoded Data |
US20180173670A1 (en) * | 2016-12-20 | 2018-06-21 | Huawei Technologies Co., Ltd. | Drive circuit and driving method for serial communications system |
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CN112867996B (en) | 2024-08-02 |
WO2020037075A1 (en) | 2020-02-20 |
EP3837612A1 (en) | 2021-06-23 |
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US20200057742A1 (en) | 2020-02-20 |
CN112867996A (en) | 2021-05-28 |
US11068428B2 (en) | 2021-07-20 |
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