Abstract: The described systems, apparatus and methods enable communication between devices that use a single-wire link and devices that use a multi-wire link. One method performed at a master device includes transmitting a sequence start condition over a data wire of a serial bus, the sequence start condition indicating whether clock pulses are to be provided in a clock signal on a clock wire of the serial bus concurrently with a transaction initiated by the sequence start condition, transmitting a first datagram over the serial bus when the sequence start condition indicates that the clock pulses are to be concurrently provided in the clock signal, and transmitting a second datagram over the serial bus when the sequence start condition indicates that no clock pulses are to be concurrently provided in the clock signal. The second datagram may be transmitted in a data signal with embedded timing information.

Abstract: Systems, methods, and apparatus for increasing register space on a slave device are described. A method performed at a device coupled to a serial bus includes receiving a datagram from a serial bus, the datagram including a command directed to a first register address in a first page of registers, writing data in a payload of the datagram to a second register address in a second page of registers when the command is a write command, and reading data from the second register address in the second page of registers when the command is a read command. The second register address is identified in the datagram when the command is a write command.

Abstract: Systems, methods, and apparatus for improving addressability of slave devices coupled to a serial bus are described. A method the slave device includes delaying transitions in a control signal received at an input pin of the slave device, enabling a counter after detecting a delayed first transition in the control signal, where the counter is configured to count pulses on a data line of a serial bus, transmitting a first pulse on the data line of the serial bus after enabling the counter, counting the first pulse and one or more additional pulses on the data line of the serial bus, and using an output of the counter to generate a unique identifier used for communicating over the serial bus. Each of a plurality of slave devices may be configured to transmit one of the additional pulses on the serial bus after the first transition occurs in the control signal.

Abstract: Thermal mitigation features may be included in a Universal Serial Bus (USB) cable assembly or in the USB receptacle portion of a device. In one aspect, one or both ends of a USB cable jacket may have greater thermal conductivity than the portion between them. The portion having the greater thermal conductivity may dissipate excess heat from the cable into the environment. In another aspect, a USB cable connector or the USB receptacle portion of a device may include a thermoelectric heat pump. The thermoelectric heat pump may move excess heat from the cable assembly or receptacle into a portion of the cable assembly or device that dissipates the heat into the environment.

Abstract: Certain aspects of the present disclosure provide an apparatus for wireless communication. The apparatus generally includes a plurality of slave radio frequency (RF) devices, a master RF device configured to set a configuration parameter in a register to be applied by an RF slave device of the plurality of RF slave devices, and a clock line coupled between the master RF device and the plurality of slave RF devices. The slave RF device may be configured to: count a number of cycles of a clock signal on the clock line; and apply the configuration parameter for the slave RF device based on the count of the number of cycles, wherein the master RF device is further configured to disable an interrupt reporting function of the plurality of slave RF device during a time period between setting the configuration parameter in the register and the configuration parameter being applied.

Abstract: Crosstalk amelioration systems and methods in a radio frequency front end (RFFE) communication system provide a host or master of an RFFE bus to monitor a weakly-driven data line in the RFFE bus while a clock line is actively providing a clock signal for trigger events at one or more slaves on the RFFE bus. If the host detects noise on the data line that looks like a sequence start condition (SSC) signal, the host further signals on the data line to negate the impact of the false SSC signal and thus avoid misinterpretation by the slaves.

Abstract: Single-counter, multi-trigger systems and methods in communication systems consolidate tracking of multiple trigger events into a single counter in place of plural counters. The single counter may track multiple trigger events for a single triggered element. Likewise, the single counter may track trigger events for a plurality of triggered elements. By consolidating tracking of trigger events with reference to a single counter, the size of the circuit may be reduced and power savings may be achieved.

Abstract: Systems, methods, and apparatus for communication over a serial bus in accordance with an I3C protocol are described that enable a slave device to request that a bus master device terminate a write transaction with the slave device. The serial bus may be operated according to an I3C single data rate protocol. In various aspects of the disclosure, a method performed at a master device coupled to a serial bus includes initiating a write transaction between the master device and a slave device, where the write transaction includes a plurality of data frames, and at least one data frame is configured with a transition bit in place of a parity bit. The method may include terminating the write transaction when the slave device drives a data line of the serial bus while receiving the transition bit.

Abstract: Systems, methods, and apparatus for improving throughput of a serial bus are described. A method performed at a device coupled to a serial bus includes detecting a transition in signaling state of a first wire of the serial bus while a first pair of consecutive bits is being received from the first wire of the serial bus, determining that no transition in signaling state of the first wire occurred while a second pair of consecutive bits is being received from the first wire, defining bit values for the first pair of consecutive bits based on direction of the transition in signaling state detected while the first pair of consecutive bits is being received, and sampling the signaling state of the first wire while the second pair of consecutive bits is being received to obtain a bit value used to represent both bits in the second pair of consecutive bits.

Abstract: Systems, methods, and apparatus for improving bus latency are described. Clock-cycle overhead associated with the transmission of trigger activation information may be reduced through the use of optimized datagram structures for register-configurable trigger activation mechanisms. A first mechanism defines a command code with a first Trigger-Activation datagram, and a second mechanism defines a command code with a second Trigger-Activation datagram that uses a 4-bit Magic-ID and eliminates 18 clock cycles from the conventional Extended Register Write datagram structure. A method performed at a device coupled to a serial bus includes generating a datagram that does not have an address field, populating a data payload of the datagram with trigger activation information directed to a plurality of slave devices coupled to a serial bus, and transmitting the datagram over the serial bus. Transmission of the datagram serves as a trigger that causes a configuration change in at least one slave device.

Abstract: A system for low-speed Peripheral Component Interconnect (PCI) Express (PCIe) systems, while maintaining both lower level physical layer (PHY) pin requirements and upper layer functionality being capable of both differential and single-ended signaling modes optimized for power savings. An apparatus includes an integrated circuit (IC) adapted to be connected to a Peripheral Component Interconnect (PCI) Express (PCIe) bus. The IC includes a control block selects between differential and single-ended signaling for the PCIe bus. The single-ended signaling is transmitted through existing pins of the IC that are coupled to the PCIe bus for differential signaling when single-ended signaling is selected for the PCIe bus.

Abstract: An enumeration technique is provided that requires no pre-assignment of addresses to slave devices connected through P2P links to a host device. With regard to any P2P link between devices, one device has a master interface and the remaining device has a slave interface. To distinguish between the master and slave interfaces, a master/slave status bit may be used. Each P2P link has a link ID that may be concatenated with the status bit for a corresponding interface (slave or master) to form a node ID. The host device receives a unique concatenated address from each slave device that represents a concatenation of the node ID for the slave and the node ID for any intervening interfaces between the slave device and the host device. The host device then assigns a unique Cartesian address to each slave device.

Abstract: Systems, methods, and apparatus for transmitting additional information over a synchronous serial bus are described. A method performed at a transmitting device coupled to the serial bus includes providing first data in a data signal to be transmitted on a first wire of a multi-wire serial bus, providing a series of pulses in a clock signal to be transmitted on a second wire of a multi-wire serial bus, where each pulse has a rising edge and a falling edge, each edge being aligned with a different bit of the first data. The method may include encoding second data in the clock signal by controlling a duration of each pulse in the series of pulses based on a value of one or more bits of the second data, and transmitting the data signal and the clock signal over the serial bus.

Abstract: Systems, methods, and apparatus for optimizing bus latency using bit-interleaved bidirectional transmission on a serial bus are described. A method performed at a device coupled to a serial bus includes pairing with a second device in a transaction to be conducted over the serial bus, transmitting a first data bit to the second device over a data line of the serial bus in a first part of each cycle in a plurality of cycles of a clock signal transmitted on a clock line of the serial bus, and receiving a second data bit transmitted by the second device on the data line in a second part of each cycle. The serial bus may be operated in accordance with an I3C, RFFE, SPMI, or other protocol.

Abstract: Systems, methods, and apparatus for one wire communication are disclosed. An apparatus has a line driver adapted to power one or more slave devices coupled to a one-wire serial bus, a circuit for encoding and decoding data in signals transmitted over the serial bus, and a controller. The line driver may maintain the wire at or above a voltage base level during transactions conducted over the wire. A data-encoded signal provided by the coding circuit may be transmitted on the wire in a first transaction and a data-encoded signal received from the wire may be decoded during a second transaction. The line driver may power the one or more slave devices when it maintains the wire at or above the first voltage level. The first signal and the second signal transitions within a voltage range defined by the first voltage level and a second voltage level.

Abstract: Systems, methods, and apparatus for communicating virtual GPIO information generated at multiple source devices and directed to multiple destination devices. A method performed at a device coupled to a serial bus includes generating first virtual GPIO state information representative of state of one or more physical GPIO output pins, asserting a request to transmit the first virtual GPIO state information by driving a data line of the serial bus from a first state to a second state after a start code has been transmitted on a serial bus and before a first clock pulse is transmitted on a clock line of the serial bus, transmitting the first virtual GPIO state information as a first set of bits in a data frame associated with the start code, and receiving second virtual GPIO state information in a second set of bits in the data frame.

Abstract: Systems, methods, and apparatus are described that enable a device to indicate availability of priority data to be communicated over a half-duplex serial bus without waiting for an ongoing transmission to be completed. In-datagram critical signaling is accommodated without breaking backward compatibility. A method implemented at a transmitting device coupled to a serial bus includes transmitting a data byte over a first line of the serial bus to a receiving device in accordance with a clock signal transmitted by a master device on a second line of the serial device, detecting a first pulse on the first line of the serial bus during a cycle of the clock signal designated for an acknowledgement or negative acknowledgement by the second device, and processing an alert indicated by the first pulse.

Abstract: Systems, methods, and apparatus for communicating datagrams over a serial communication link are provided. A transmitting device generates an address field in a datagram, sets a value of at least one bit in the address field to indicate a number of bytes of data associated with a data frame of the datagram, generates the data frame in the datagram, the data frame including the number of bytes of data, and sends the datagram to a receiving device. A receiving device receives a datagram from a transmitting device, decodes an address field of the datagram to detect a number of bytes of data included in a data frame of the datagram based on a value of at least one bit in the address field, and decodes the data frame to recover the detected number of bytes of data.

Abstract: Increased data rates over a serial bus are enabled without increasing clock frequency. A method performed at a device coupled to a serial datalink includes transmitting a one-bit sequence start condition over a data wire of a datalink, providing a command field in the pulse-width modulated datagram, where a first-transmitted bit of the command field identifies the datagram as a write command directed to a register located at address zero, and providing data in a third-transmitted bit and subsequently-transmitted bits of the command field to be written to the register located at address zero when a second-transmitted bit of the command field has a first value. The sequence start condition has a first edge that commences transmission of a pulse-width modulated datagram and a second edge that indicates an optimal sampling point in each bit period of the pulse-width modulated datagram.

Abstract: Aspects of the disclosure are directed to a System on a Chip (SOC). In accordance with one aspect, a method for implementing back power protection (BPP) in a SOC includes transmitting a first back power protection (BPP) supply output from a first power management integrated circuit (PMIC) to a logical OR function; transmitting a second back power protection (BPP) supply output from a second power management integrated circuit (PMIC) to the logical OR function; using the logical OR function to generate a composite BPP power based on the first BPP supply output and the second BPP supply output; and inputting the composite BPP power to a baseband processor (BP), wherein the baseband processor (BP) is coupled to the second PMIC.