Abstract: A serial bus repeater includes a port circuit and a low power state detection circuit. The port circuit is configured to communicate via a serial bus. The low power state detection circuit includes a power state transaction identification circuit and a bus state identification circuit. The power state transaction identification circuit is configured to identify a power state transaction on the serial bus. The power state transaction is indicative of entering a reduced power state. The bus state identification circuit is configured to identify a value of termination resistance on the serial bus that is indicative of entering the reduced power state.

Abstract: 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.

Abstract: A serial bus signal conditioner circuit includes receiver circuitry, a mode identification circuit, and an edge-rate booster circuit. The receiver circuitry is configured to receive signals transmitted on a serial bus. The mode identification circuit is coupled to the receiver circuitry, and is configured to identify initiation of or return to high-speed signaling on the serial bus based on sequences of the signals transmitted on the serial bus. The edge-rate booster circuit is coupled to the mode identification circuit, and is configured to identify edges of a differential signal transmitted on the serial bus, and to supply a differential current to the serial bus based on identification of an edge of the differential signal.

Abstract: Aspects of the disclosure provide for a method. In at least some examples, the method includes receiving, at a circuit, data via a differential input signal. The method further includes detecting a falling edge in the data received via the differential input signal. The method further includes holding an output of the circuit at a final logical value of the data. The method further includes disabling a transmitter of the circuit while holding the output of the circuit at the final logical value of the data. The method further includes releasing the output of the circuit from the final logical value of the data.

Abstract: An input/output (I/O) level shifter for a subscriber identification module (SIM) interface includes a controller configured to apply a first enable signal to turn ON a first transmitter when the direction of packet flow is from an interface device to a SIM card, and is configured to apply a second enable signal to turn ON a second transmitter when the direction of packet flow is from the SIM card to the interface device. The controller is configured to not apply the first and the second enable signals concurrently. The controller selectively controls the ON/OFF period of the first and the second transmitter to maintain half-duplex communication on the interface I/O line and the SIM I/O line to prevent undesired positive data feedback.

Abstract: Aspects of the disclosure provide for a circuit including a squelch detector having a first input coupled to a first node and configured to receive a positive component of a differential signal with a floating center tap, a second input coupled to a second node and configured to receive a negative component of the differential signal, and an output coupled to a logic circuit, a first resistor coupled between the first node and a third node, a second resistor coupled between the third node and the second node, a third resistor coupled between the first node and a fourth node, a fourth resistor coupled between the fourth node and the second node, a capacitor coupled between the fourth node and a ground terminal, a comparator having a first input coupled to the third node, a second input coupled to a fifth node, and an output coupled to the logic circuit.

Abstract: A method of operating an embedded USB2 (eUSB2) repeater includes receiving a downstream packet at a USB2 port and transitioning a USB transmitter from an idle state to a standby state responsive to receiving the downstream packet. The method further includes transitioning the USB transmitter from the standby state to an active state if an upstream packet is received at an eUSB2 port within a first time period of receiving the downstream packet and transmitting the upstream packet. The method also includes transitioning the USB transmitter from the active state to the standby state after transmission of the upstream packet. The method also includes transitioning the USB transmitter from the standby state to the idle state if more upstream packets are not received at the eUSB2 port within a second time period.

Abstract: Aspects of the present disclosure provide for a method. In at least some examples, the method includes controlling a switch to decouple a first node at which a pull-up signal is present from a second node. The method further includes measuring and storing a value of the pull-up signal as a reference value. The method further includes controlling the switch to couple the first node at which the pull-up signal is present to the second node. The method further includes determining whether a pull-down signal is present at the second node by comparing the reference value to a value of a signal present at the second node.

Abstract: Circuit including a first port to couple to a first device; a second port to couple to a second device; a first channel having an input coupled to first port and an output coupled to second port, the first channel to re-drive a signal and output re-driven signal; a second channel having an input coupled to second port and an output coupled to first port, the second channel to re-drive a signal and output re-driven signal; and a controller to: enable first channel and disable second channel responsive to detecting a signal edge at first port; enable second channel and disable first channel responsive to detecting a signal edge at second port; sample impedance at first port if signal received at first port is de-asserted while first channel is enabled; and sample impedance at second port if signal received at second port is de-asserted while second channel is enabled.

Abstract: Aspects of the disclosure provide for a circuit including a squelch detector having a first input coupled to a first node and configured to receive a positive component of a differential signal with a floating center tap, a second input coupled to a second node and configured to receive a negative component of the differential signal, and an output coupled to a logic circuit, a first resistor coupled between the first node and a third node, a second resistor coupled between the third node and the second node, a third resistor coupled between the first node and a fourth node, a fourth resistor coupled between the fourth node and the second node, a capacitor coupled between the fourth node and a ground terminal, a comparator having a first input coupled to the third node, a second input coupled to a fifth node, and an output coupled to the logic circuit.

Abstract: At least some aspects of the present disclosure provide for a method. In some examples, the method includes receiving 2-line data in an embedded Universal Serial Bus (eUSB) format. The method further includes encoding the 2-line data into a single signal. The single signal comprises a first symbol corresponding to a first state change of the 2-line data and a second symbol corresponding to a second state change of the 2-line data.

Abstract: A system includes an eUSB2 transmitter, wherein the eUSB2 transmitter is configured to provide a data set comprising a data packet, default sync bits, and surplus sync bits. The system also includes an eUSB2 to USB 2.0 repeater coupled to the eUSB2 transmitter, wherein the eUSB2 to USB 2.0 repeater is configured to remove the surplus sync bits and to output the data packet and the default sync bits.

Abstract: Aspects of the disclosure provide for a circuit including a squelch detector having a first input coupled to a first node and configured to receive a positive component of a differential signal with a floating center tap, a second input coupled to a second node and configured to receive a negative component of the differential signal, and an output coupled to a logic circuit, a first resistor coupled between the first node and a third node, a second resistor coupled between the third node and the second node, a third resistor coupled between the first node and a fourth node, a fourth resistor coupled between the fourth node and the second node, a capacitor coupled between the fourth node and a ground terminal, a comparator having a first input coupled to the third node, a second input coupled to a fifth node, and an output coupled to the logic circuit.

Abstract: Aspects of the disclosure provide for a method. In at least some examples, the method includes receiving, at a circuit, data via a differential input signal. The method further includes detecting a falling edge in the data received via the differential input signal. The method further includes holding an output of the circuit at a final logical value of the data. The method further includes disabling a transmitter of the circuit while holding the output of the circuit at the final logical value of the data. The method further includes releasing the output of the circuit from the final logical value of the data.

Abstract: A method of operating an embedded USB2 (eUSB2) repeater includes receiving a downstream packet at a USB2 port and transitioning a USB transmitter from an idle state to a standby state responsive to receiving the downstream packet. The method further includes transitioning the USB transmitter from the standby state to an active state if an upstream packet is received at an eUSB2 port within a first time period of receiving the downstream packet and transmitting the upstream packet. The method also includes transitioning the USB transmitter from the active state to the standby state after transmission of the upstream packet. The method also includes transitioning the USB transmitter from the standby state to the idle state if more upstream packets are not received at the eUSB2 port within a second time period.

Abstract: A method includes detecting a micro start of frame packet (?SOF) on a data bus. If there is at least one data packet contained in a microframe during the first threshold period after the ?SOF, transmitters are held in an active state. If there is no data packet in the first threshold period after the ?SOF, the transmitters are transitioned from the active state to an OFF state. The method also includes transitioning the transmitters from the OFF state to the active state prior to a switchback period before the end of the microframe. The method also includes transitioning the transmitters from the OFF state to the active state if a data packet is received in the OFF state. The method also includes dropping the data packet received in the OFF state and transitioning from the OFF state to the active state when the data packet is dropped.

Abstract: A serial bus signal conditioner circuit includes receiver circuitry, a mode identification circuit, and an edge-rate booster circuit. The receiver circuitry is configured to receive signals transmitted on a serial bus. The mode identification circuit is coupled to the receiver circuitry, and is configured to identify initiation of or return to high-speed signaling on the serial bus based on sequences of the signals transmitted on the serial bus. The edge-rate booster circuit is coupled to the mode identification circuit, and is configured to identify edges of a differential signal transmitted on the serial bus, and to supply a differential current to the serial bus based on identification of an edge of the differential signal.

Abstract: An input/output (I/O) level shifter for a subscriber identification module (SIM) interface includes a controller configured to apply a first enable signal to turn ON a first transmitter when the direction of packet flow is from an interface device to a SIM card, and is configured to apply a second enable signal to turn ON a second transmitter when the direction of packet flow is from the SIM card to the interface device. The controller is configured to not apply the first and the second enable signals concurrently. The controller selectively controls the ON/OFF period of the first and the second transmitter to maintain half-duplex communication on the interface I/O line and the SIM I/O line to prevent undesired positive data feedback.

Abstract: Aspects of the disclosure provide for a method. In at least some examples, the method includes receiving, at a circuit, data via a differential input signal. The method further includes detecting a falling edge in the data received via the differential input signal. The method further includes holding an output of the circuit at a final logical value of the data. The method further includes disabling a transmitter of the circuit while holding the output of the circuit at the final logical value of the data. The method further includes releasing the output of the circuit from the final logical value of the data.

Abstract: Aspects of the disclosure provide for a method. In at least some examples, the method includes receiving, at a circuit, data via a differential input signal. The method further includes detecting a falling edge in the data received via the differential input signal. The method further includes holding an output of the circuit at a final logical value of the data. The method further includes disabling a transmitter of the circuit while holding the output of the circuit at the final logical value of the data. The method further includes releasing the output of the circuit from the final logical value of the data.