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: An apparatus has a plurality of multi-level comparison circuits, each coupled to a pair of wires in a three-wire communication link, a plurality of first-level clock recovery circuits and a second-level clock recovery circuit. Each multi-level comparison circuit provides a multibit signal as an output. Each first-level clock recovery circuit includes a plurality of first-level flipflops clocked by transitions in a multibit signal received from one multi-level comparison circuit of the plurality of multi-level comparison circuits, and a first delay circuit that delays an output of the each first-level clock recovery circuit to provide a first reset signal that resets the each first-level clock recovery circuit.

Abstract: Methods, apparatus, and systems for communication over a C-PHY interface are disclosed. A transmitting device has a driver circuit configured to drive a three-wire bus in accordance with a symbol received at an input of the driver circuit, a pattern detector receives a sequence of symbols to be transmitted over the three-wire bus in a plurality of transmission symbol intervals, and a selection circuit responsive to a select signal provided by the pattern detector and configured to select between delayed and undelayed versions of a current symbol to drive the input of the driver circuit during a corresponding transmission symbol interval. The select signal may select the delayed version of the current symbol when a combination of the current symbol with an immediately preceding symbol cause the pattern detector to indicate a pattern match.

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: Methods, apparatus, and systems for communication over a C-PHY interface are disclosed. A transmitting device has a driver circuit configured to drive a three-wire bus in accordance with a symbol received at an input of the driver circuit, a pattern detector receives a sequence of symbols to be transmitted over the three-wire bus in a plurality of transmission symbol intervals, and a selection circuit responsive to a select signal provided by the pattern detector and configured to select between delayed and undelayed versions of a current symbol to drive the input of the driver circuit during a corresponding transmission symbol interval. The select signal may select the delayed version of the current symbol when a combination of the current symbol with an immediately preceding symbol cause the pattern detector to indicate a pattern match.

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: Certain disclosed methods, apparatus, and systems enable improved communication on a multiphase communication link through improved encoding techniques and protocol. A data communication apparatus has a plurality of line drivers configured to couple the apparatus to a 3-wire link, and a data encoder configured to encode at least 3 bits of binary data in each transition between two symbols that are consecutively transmitted by the plurality of line drivers over the 3-wire link such that each pair of consecutively-transmitted symbols comprises two different symbols. Each symbol defines signaling states of the 3-wire link during an associated symbol transmission interval such that each wire of the 3-wire link is in a different signaling state from the other wires of the 3-wire link during the associated symbol transmission interval. Data may be encoded using a combination of 3-phase and pulse amplitude modulation.

Abstract: Certain disclosed methods, apparatus, and systems enable improved communication on a multiphase communication link through improved encoding techniques and protocol. A data communication apparatus has a plurality of line drivers configured to couple the apparatus to a 3-wire link, and a data encoder configured to encode at least 3 bits of binary data in each transition between two symbols that are consecutively transmitted by the plurality of line drivers over the 3-wire link such that each pair of consecutively-transmitted symbols comprises two different symbols. Each symbol defines signaling states of the 3-wire link during an associated symbol transmission interval such that each wire of the 3-wire link is in a different signaling state from the other wires of the 3-wire link during the associated symbol transmission interval. Data may be encoded using a combination of 3-phase and pulse amplitude modulation.

Abstract: Systems, methods and apparatus are described that facilitate transmission of data between two devices within an electronic apparatus. A data transfer method includes receiving from a three-wire interface, a first packet of data encoded in a first sequence of symbols representing transitions in signaling state of the three wires, and transmitting on the three-wire interface, a second packet of data encoded in a second sequence of symbols representing transitions in signaling state of the three wires. The first sequence of symbols may include up to five types of symbol. The second sequence of symbols may include two or three types of symbol.

Abstract: Methods, apparatus, and systems for data communication over a multi-wire, multi-phase interface are disclosed. A method includes equalizing three-phase signals received from two wires of the interface to provide equalized signals, providing first and second difference signals by comparing voltage differences between the equalized signals with first and second reference voltage levels respectively, capturing delayed and undelayed versions of the second difference signal using flipflops triggered by different edges in the first difference signal, and adjusting an equalizing circuit until outputs of the first flipflops indicate that a ratio of low-frequency attenuation to high-frequency amplification has been achieved that enables information to be accurately decoded from the three-phase signals. The three-phase signal received from a first of the two wires is in a different phase than the three-phase signal received from a second of the two wires.

Abstract: System, methods and apparatus are described that support multimode operation of a data communication interface. A method performed in a device coupled to a multi-wire bus includes configuring a bus interface to drive the multi-wire bus in a high-speed mode, transmitting a plurality of symbols over the multi-wire bus while the bus interface is configured to drive the multi-wire bus in the high-speed mode, providing a control sequence of symbols in the plurality of symbols, and configuring the bus interface to operate as a receiver in the high-speed mode when the control code comprises a turnaround code. The first data may be encoded in the plurality of symbols. The control sequence of symbols may include a control code that is transmitted between two synchronizing sequences of symbols.

Abstract: Systems, methods and apparatus are described that facilitate transmission of data between two devices within an electronic apparatus. An apparatus has a bus interface, a 3-phase encoder, and a processing circuit that can configure the 3-phase encoder for a first mode of operation in which data is encoded in a sequence of two-bit symbols, transmit a first three-phase signal representative of the sequence of two-bit symbols on each of the three wires. The processing circuit may be configured to configure the 3-phase encoder for a second mode of operation in which data is encoded in a sequence of three-bit symbols. Three-phase signal representative of the sequence of two-bit symbols or sequence of three-bit symbols on each of three wires, where a three-phase signal is in a different phase on each wire when transmitted, and a transition in signaling state occurs between transmission of each pair of symbols.

Abstract: To accommodate multiple masters over bus architectures supporting a single master device, a mechanism is provided for an inactive master device to assert an in-band IRQ. A current master then polls the other inactive master devices over a shared data bus to ascertain which inactive master device is asserting the IRQ. Upon identifying the asserting inactive master device, the current master device grants control of the data bus to the new master device, thereby making the inactive master the new active master device.

Abstract: Systems, methods and apparatus are described that facilitate transmission of data between two devices within an electronic apparatus. A data transfer method includes receiving from a three-wire interface, a first packet of data encoded in a first sequence of symbols representing transitions in signaling state of the three wires, and transmitting on the three-wire interface, a second packet of data encoded in a second sequence of symbols representing transitions in signaling state of the three wires. The first sequence of symbols may include up to five types of symbol. The second sequence of symbols may include two or three types of symbol.

Abstract: A method for error detection in transmissions on a multi-wire interface includes providing a plurality of launch clock signals, including launch clock signals having a different phase shifts, determining a type of transition in signaling state that will occur on each wire of the 3-wire interface at a boundary between two consecutively transmitted symbols, and selecting one of the plurality of launch clock signals to initiate the transition of signaling state on each wire of the 3-phase interface. Selecting one of the plurality of launch clock signals may include selecting a first launch clock signal when the transition in signaling state terminates at an undriven state, and selecting a second launch clock signal when the transition in signaling state begins at an undriven state. An edge in the first launch clock signal may occur before a corresponding edge in the second launch clock signal.

Abstract: Methods, apparatus, and systems for data communication over a multi-wire, multi-phase interface are disclosed. A method includes recovering a first clock signal from transitions between pairs of symbols representative of successive signaling states of a 3-wire interface, where a pulse in the first clock signal is generated in response to an earliest-occurring transition between the first and second symbols in one of three difference signals representative of differences in state between two wires, determining direction of voltage change of a first transition detected on a first difference signal, providing a value selected based on the direction of voltage change as value of the first difference signal in the second symbol, and providing a value of a second difference signal captured during the first symbol as the value of the second difference signal when the second difference signal does not transition between the first symbol and the second symbol.

Abstract: Systems, methods and apparatus are described that facilitate transmission of data between two devices within an electronic apparatus. An apparatus has a bus interface, a 3-phase encoder, and a processing circuit that can configure the 3-phase encoder for a first mode of operation in which data is encoded in a sequence of two-bit symbols, transmit a first three-phase signal representative of the sequence of two-bit symbols on each of the three wires. The processing circuit may be configured to configure the 3-phase encoder for a second mode of operation in which data is encoded in a sequence of three-bit symbols. Three-phase signal representative of the sequence of two-bit symbols or sequence of three-bit symbols on each of three wires, where a three-phase signal is in a different phase on each wire when transmitted, and a transition in signaling state occurs between transmission of each pair of symbols.

Abstract: System, methods and apparatus are described that facilitate transmission of data, particularly between two devices within an electronic apparatus. Data is selectively transmitted as N-phase polarity encoded symbols or as packets on differentially driven connectors. A data transfer method comprises encoding data and control signals in a sequence of symbols to be transmitted on a plurality of connectors, and transmitting the sequence of symbols on the plurality of connectors. Each symbol may be transmitted using a combination of a phase state of a first pair of connectors, a polarity of a second pair of connectors, and a selection of at least one undriven connector. Transmission of each symbol in the sequence of symbols may cause a change of state for at least one of the plurality of connectors.

Abstract: System, methods and apparatus are described that facilitate transmission of data, particularly between two devices within an electronic apparatus. Information is transmitted in N-phase polarity encoded symbols. Drivers may be adapted or configured to align state transitions on two or more connectors in order to minimize a transition period between consecutive symbols. The drivers may include circuits that advance or delay certain transitions. The drivers may include pre-emphasis circuits that operate to drive the state of a connector for a portion of the transition period, even when the connector is transitioned to an undriven state.