Abstract: Systems, methods, and apparatus improve synchronization of trigger timing when triggers are configured over a serial bus. A data communication apparatus has an interface circuit that couples the data communication apparatus to a serial bus and is configured to receive a clock signal from the serial bus, a plurality of counters configured to count pulses in the clock signal, and a controller configured to receive a datagram from the serial bus, the datagram including a plurality of data bytes corresponding to the plurality of counters, configure each of the plurality of counters with a count value based on content of a corresponding data byte when the corresponding data byte is received from the datagram, cause each of the counters to refrain from counting until all of the counters have been configured with count values, and actuate a trigger when a counter associated with the trigger has counted to zero.

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 and methods for variable stride counting for timed-triggers in a radio frequency front end (RFFE) bus modify how a master clock controls counters in slaves. In particular, instead of having the master clock change a counter at a slave device on a one-to-one clock tick-to-counter change, exemplary aspects of the present disclosure contemplate allowing a bus ownership master (BOM) to select a stride size wherein each clock tick causes the counter to change by the size of the stride. Clock ticks are then sent less frequently over the clock line of the RFFE bus. In this fashion, fewer clock ticks are required to change the counter to the trigger event.

Abstract: Sideband signaling in Universal Serial Bus (USB) Type-C communication link allows multiple protocols that are tunneled through a USB link, where sideband signals may be provided through the sideband use (SBU) pins. Further, the SBU pins may be transitioned between different modes of sideband signals. In particular, signals in an initial mode may indicate a need or desire transition to a second mode. After a negotiation, linked devices agree to transition, the two devices may transition to the second mode. By providing this inband sideband signaling that allows mode changes, more protocols can be tunneled with accompanying sideband signaling and flexibility of the USB link is expanded.

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: Alternate sideband signaling in a Peripheral Component Interconnect (PCI) express (PCIE) link may be enabled over existing sideband lines in a conventional PCIE link. For example, the default sideband communication of PCIE may be changed to a Universal Asynchronous receiver/transmitter (UART), line multiplex UART (LM-UART), serial peripheral interface (SPI), I2C, or I3C mode of communication. This change may be negotiated between the host and slave of the communication link, with a transition occurring after the negotiation concludes. The new mode of communication may include or encode the conventional PCIE sideband signals.

Abstract: Expanded function datagrams in a system power management interface (SPMI) system allow a slave to use an expanded function datagram to address a larger number of masters (e.g., more than four) associated with the SPMI system. Furthermore, addressing may allow for a datagram to be broadcast to multiple masters concurrently. Still further, by signaling that the master addressing is other than the standard SPMI format, the nature of the address and payload of a datagram may be varied to handle larger volumes of data than the SPMI standard normally allows.

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: Expanded function datagrams in a system power management interface (SPMI) system allow a slave to use an expanded function datagram to address a larger number of masters (e.g., more than four) associated with the SPMI system. Furthermore, addressing may allow for a datagram to be broadcast to multiple masters concurrently. Still further, by signaling that the master addressing is other than the standard SPMI format, the nature of the address and payload of a datagram may be varied to handle larger volumes of data than the SPMI standard normally allows.

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 multi-drop coexistence management are described. A data communication apparatus has a bus interface that couples the data communication apparatus to a serial bus and a controller configured to determine that a datagram received from the serial bus is addressed to a register address corresponding to a coexistence management identifier, activate a line driver of the bus interface circuit that is coupled to a data line of the serial bus during a portion of a first payload of the datagram when one or more coexistence management messages are ready for sending from the slave device, where the portion of the first payload of the datagram is allocated for use of the apparatus, and transmit a first coexistence management message in the portion of the first payload of the datagram that is allocated for use of the data communication apparatus.

Abstract: Systems, methods, and apparatus for multi-drop coexistence management are described. A data communication apparatus has a bus interface that couples the data communication apparatus to a serial bus and a controller configured to determine that a datagram received from the serial bus is addressed to a register address corresponding to a coexistence management identifier, activate a line driver of the bus interface circuit that is coupled to a data line of the serial bus during a portion of a first payload of the datagram when one or more coexistence management messages are ready for sending from the slave device, where the portion of the first payload of the datagram is allocated for use of the apparatus, and transmit a first coexistence management message in the portion of the first payload of the datagram that is allocated for use of the data communication apparatus.

Abstract: Systems, methods, and apparatus improve accuracy of trigger timing by compensating for clock pulses that are suppressed when datagrams are transmitted over a serial bus. A method includes configuring an initial value of an output of a counter in a timing circuit, enabling the counter to count pulses in a clock signal received from the serial bus, determining that a datagram is being transmitted on the serial bus while the counter is counting the pulses in the clock signal, providing a timing value that represents a current value of the output of the counter adjusted to compensate for one or more clock pulses suppressed during transmission of the datagram, and providing a trigger when the timing value reaches a maximum value or a minimum value. The counter may be a countdown counter and two clock pulses may be suppressed for each sequence start condition transmitted on the serial bus.

Abstract: Systems, methods, and apparatus increase the number of slave devices that can be connected to a serial bus. The bus protocol may be an RFFE protocol, an SPMI protocol, an I3C protocol or another protocol usable on a serial bus. In various aspects of the disclosure, a method performed at a device coupled to a serial bus includes receiving a first datagram at a slave device coupled to a serial bus, where the first datagram includes a 4-bit broadcast address indicative of a broadcast datagram, a first command directed to an invalid register address, and a payload, determining an encapsulation protocol associated with the invalid register address, and responding to a second command carried in the payload when an 8-bit slave address in the payload matches an 8-bit slave identifier allocated to the slave device.

Abstract: An apparatus includes an interface circuit adapted to couple the apparatus to a serial bus, a slot counter, and a processor. The slot counter may be configured to monitor a radio frequency coexistence management cycle that includes a plurality of time slots. The processor may be configured to transmit a first datagram through the interface circuit during a first time slot in the plurality of time slots. The apparatus may be uniquely permitted to initiate transactions over the serial bus during the first time slot. The processor may be further configured to participate in an arbitration procedure during a second time slot in the plurality of time slots. More than one device coupled to the serial bus may be permitted to initiate transactions in the second time slot.

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: Unified systems and methods for interchip and intrachip node communication are disclosed. In one aspect, a single unified low-speed bus is provided that connects each of the chips within a computing device. The chips couple to the bus through a physical layer interface and associated gateway. The gateway includes memory that stores a status table summarizing statuses for every node in the interface fabric. As nodes experience state changes, the nodes provide updates to associated local gateways. The local gateways then message, using a scout message, remote gateways with information relating to the state changes. When a first node is preparing a signal to a second node, the first node checks the status table at the associated local gateway to determine a current status for the second node. Based on the status of the second node, the first node may send the message or take other appropriate action.

Abstract: Systems, methods, and apparatus increase the number of slave devices that can be connected to a serial bus. The bus protocol may be an RFFE protocol, an SPMI protocol, an I3C protocol or another protocol usable on a serial bus. In various aspects of the disclosure, a method performed at a device coupled to a serial bus includes receiving a first datagram at a slave device coupled to a serial bus, where the first datagram includes a 4-bit broadcast address indicative of a broadcast datagram, a first command directed to an invalid register address, and a payload, determining an encapsulation protocol associated with the invalid register address, and responding to a second command carried in the payload when an 8-bit slave address in the payload matches an 8-bit slave identifier allocated to the slave device.

Abstract: Systems, methods, and apparatus for improving bus latency for trigger activation are described. One method includes using configuration information received from a serial bus and stored in a holding register to reconfigure a peripheral device in accordance with timing indicated by at least one edge in clock pulses transmitted on a clock line of the serial bus. A trigger is activated by detection of a first edge in the clock pulses. Bits of the holding register are transferred to a register that controls elements of the peripheral device when the trigger is actuated. The trigger may be activated as indicated by trigger activation information received in a datagram. The trigger may be activated as indicated by a start condition transmitted on the serial bus. The trigger may be enabled or disabled based on signaling state of a data line of the serial bus when the first edge is detected.