Abstract: A multi-port data communication apparatus includes a first port having a first physical interface circuit configured to couple the multi-port data communication apparatus to a first serial bus that has a first line and a second line, a second port having a second physical interface circuit configured to couple the multi-port data communication apparatus to a second serial bus that has a first line and a second line, and a controller. The controller is configured to use the first port during a first transaction restricted to transmissions over the first serial bus and use the first port and the second port in a second transaction in which data is transmitted over the second line of the first serial bus and the second line of the second serial bus in accordance with timing provided by a clock signal transmitted over the first line of the first serial bus.

Abstract: Systems and methods for chip operation using serial peripheral interface (SPI) with reduced pin options contemplate eliminating the chip select pins, interrupt pins and/or reset pins for host (also referred to as master)-to-device (also referred to as slave) communication links, while preserving the possibility of backward compatibility for legacy devices if desired. The communication link may include a clock line, a host-to-device line, and a device-to-host line. The host may use specific sequences of signals on the clock and host-to-device line to provide start and stop sequence commands, interrupts, or reset commands. By consolidating these commands onto the clock and host-to-device line, pin count may be reduced for portions of the host and slave circuits. Likewise, fewer (or at least shorter potentially) conductive traces may be needed to interconnect the host to the device. Such changes may save cost, make layout design easier, and/or save space within a computing device.

Abstract: Systems and methods for chip operation using serial peripheral interface (SPI) with reduced pin options contemplate eliminating the chip select pins, interrupt pins and/or reset pins for host (also referred to as master)-to-device (also referred to as slave) communication links, while preserving the possibility of backward compatibility for legacy devices if desired. The communication link may include a clock line, a host-to-device line, and a device-to-host line. The host may use specific sequences of signals on the clock and host-to-device line to provide start and stop sequence commands, interrupts, or reset commands. By consolidating these commands onto the clock and host-to-device line, pin count may be reduced for portions of the host and slave circuits. Likewise, fewer (or at least shorter potentially) conductive traces may be needed to interconnect the host to the device. Such changes may save cost, make layout design easier, and/or save space within a computing device.

Abstract: Systems, methods, and apparatus for error signaling on a serial bus are described. An apparatus includes a bus interface configured to couple the apparatus to a serial bus, a phase-differential decoder configured to decode data from transitions between pairs of symbols in a sequence of symbols received from the serial bus, each symbol being representative of signaling state of the serial bus, and a processor configured to detect an indicator of an error signaling window in signaling state of two wires of the serial bus, the indicator of the error signaling window corresponding to a prohibited combination of symbols or a delay in control signaling, signaling an error through the bus interface during the error signaling window when an error is detected in the sequence of symbols or in timing of the indicator of the error signaling window.

Abstract: Systems, methods, apparatus and techniques are described that provide point-to-point capabilities without the expected increase in input/output pad usage. In some examples, point-to-point data lines are provided between a host and multiple slave devices and timing of communication is controlled using a clock signal shared by the multiple slave devices. An apparatus has a plurality of bus master circuits configured to control point-to-point communication with corresponding slave devices and a clock generation circuit configured to provide pulses in a serial bus clock signal when one or more bus master circuits are in an active state, and further to idle the serial bus clock signal when all bus master circuits are idle. Each bus master circuit may be configured to communicate with its corresponding slave device in accordance with the timing provided by the serial bus clock signal that is transmitted over a common clock line to each slave device.

Abstract: Systems, methods, and apparatus for communication virtualized general-purpose input/output (GPIO) signals and control messages over a serial communication link. An apparatus includes a serial bus, and a controller configured to represent a series of signaling state of physical general-purpose input/output (GPIO) in a batch that comprises a sequence of virtual GPIO messages and control messages, generate a first header that includes timing information configured to control timing of execution of the batch, transmit the first header over a communication link, and transmit the batch over the communication link.

Abstract: Systems, methods, apparatus and techniques are described that provide point-to-point capabilities without the expected increase in input/output pad usage. In some examples, point-to-point data lines are provided between a host and multiple slave devices and timing of communication is controlled using a clock signal shared by the multiple slave devices. An apparatus has a plurality of bus master circuits configured to control point-to-point communication with corresponding slave devices and a clock generation circuit configured to provide pulses in a serial bus clock signal when one or more bus master circuits are in an active state, and further to idle the serial bus clock signal when all bus master circuits are idle. Each bus master circuit may be configured to communicate with its corresponding slave device in accordance with the timing provided by the serial bus clock signal that is transmitted over a common clock line to each slave device.

Abstract: Pulse amplitude modulation (PAM) encoding for a communication bus is disclosed. In particular, various two-wire communication buses may encode bits using three-level PAM (PAM-3) or five-level PAM (PAM-5) to increase bit transmission without requiring increases to clock frequencies or adding additional pins. Avoiding increases in clock frequencies helps reduce the risk of electromagnetic interference (EMI), and avoiding use of extra pins avoids cost increases for integrated circuits (ICs).

Abstract: Pulse amplitude modulation (PAM) encoding for a communication bus is disclosed. In particular, various two-wire communication buses may encode bits using three-level PAM (PAM-3) or five-level PAM (PAM-5) to increase bit transmission without requiring increases to clock frequencies or adding additional pins. Avoiding increases in clock frequencies helps reduce the risk of electromagnetic interference (EMI), and avoiding use of extra pins avoids cost increases for integrated circuits (ICs).

Abstract: Systems, methods, and apparatus for communication virtualized general-purpose input/output (GPIO) signals and control messages over a serial communication link. An apparatus includes a serial bus, and a controller configured to represent a series of signaling state of physical general-purpose input/output (GPIO) in a batch that comprises a sequence of virtual GPIO messages and control messages, generate a first header that includes timing information configured to control timing of execution of the batch, transmit the first header over a communication link, and transmit the batch over the communication link.

Abstract: Systems, methods, and apparatus for error signaling on a serial bus are described. An apparatus includes a bus interface configured to couple the apparatus to a serial bus, a phase-differential decoder configured to decode data from transitions between pairs of symbols in a sequence of symbols received from the serial bus, each symbol being representative of signaling state of the serial bus, and a processor configured to detect an indicator of an error signaling window in signaling state of two wires of the serial bus, the indicator of the error signaling window corresponding to a prohibited combination of symbols or a delay in control signaling, signaling an error through the bus interface during the error signaling window when an error is detected in the sequence of symbols or in timing of the indicator of the error signaling window.

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 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: Disclosed are methods and apparatus for calculating sensor timing corrections at a sensor device. The methods and apparatus determine a sampling period as a number of cycles of an internal clock counted while a configured number of samples is captured in a slave device, determine a time interval between samples using an offset from a time of an observed occurrence of a hardware event on a communication link, the offset being received in a command from a master device, and adjust the time interval between samples by iterative digital approximation to correct for differences between timing of the slave device and the master device while concurrently calculating a watermark time corresponding to a sample start time configured by the master device for one or more slave devices.

Abstract: Systems, methods, and apparatus for serial bus arbitration are described. A method for managing transactions executed on a serial bus includes configuring a slave device with information identifying a first timeslot in a first transaction type that is conducted repetitively in accordance with a repetitive time period (RTP) schedule, initiating a first transaction of the first transaction type at a first point in time that is defined by the RTP schedule, and exchanging first data with the slave device during the first timeslot in the first transaction. The serial bus may be operated in accordance with an asynchronous protocol. In one example, the asynchronous protocol is an I3C protocol.

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 are described that enable a serial bus to be operated in one or more modes that employ additional wires for communicating data. A method includes providing a data payload for a first data frame to be transmitted over a plurality of data lanes of a multilane serial bus operated in accordance with an I3C protocol, providing one or more indicators of validity of one or more bytes included in the data payload, and transmitting the first data frame over the multilane serial bus in accordance with a clock signal transmitted on a clock lane of the multilane serial bus.

Abstract: Systems, methods, and apparatus are described that enable a serial bus to be operated in one or more modes that employ additional wires for communicating data. A method includes configuring a first interface to exchange data over two primary wires of a serial bus in accordance with a first I3C protocol, and configuring a second interface to communicate over at least one secondary wire in accordance with a second I3C protocol. In one example, the first data is encoded in a sequence of symbols representing signaling state of the two primary wires. A recovered clock signal may be derived from transitions between symbol transmission intervals in the first interface may be used to control double data rate communication through the second interface.

Abstract: Systems, methods, and apparatus are described that enable a serial bus to be operated in one or more modes including a mode that encodes data in a clock signal. A method includes providing a clock signal that controls timing of transactions conducted over a serial bus, transmitting a first pair of data bytes at double data rate over a first wire of the serial bus in a first transaction, modulating the clock signal during the first transaction to provide a modulated clock signal that encodes at least one additional data byte, and transmitting the modulated clock signal over a second wire of the serial bus during the first transaction.

Abstract: Systems, methods, and apparatus are described that enable a serial bus to be operated in one or more modes that employ additional wires for communicating data. A method includes configuring a first interface to exchange data over two primary wires of a serial bus in accordance with a first I3C protocol, and configuring a second interface to communicate over at least one secondary wire in accordance with a second I3C protocol. In one example, the first data is encoded in a sequence of symbols representing signaling state of the two primary wires. A recovered clock signal may be derived from transitions between symbol transmission intervals in the first interface may be used to control double data rate communication through the second interface.