A serial communication protocol for daisy-chained slave devices does away with the requirement for an entire byte of dummy clocks to be cycled between a slave's input and output, instead requiring a shorter set of dummy clock cycles which improves efficiency of a serial communication system. According to a specification of a serial communications protocol, data is exchanged between master and slave devices in communication frames. Each communication frame has a command portion and a data portion, and each respective portion may comprise packages of one or more bytes.

A method for operating a data interface circuit whereby calibration adjustments for data bit capture are made without disturbing normal system operation includes initially establishing, using a first calibration method where a data bit pattern received by the data interface circuit is predictable, an optimal sampling point for sampling data bits received by the data interface circuit, and during a normal system operation and without disturbing the normal system operation, performing a second calibration method where the data bit pattern received by the data interface circuit is unpredictable. The second calibration method determines an amount of a timing drift for received data bit edge transitions and adjusts the optimal timing point determined by the first calibration method to create a revised optimal timing point. The second calibration method samples fringe timing points associated with the transition edges of a data bit.

A memory module is operable in a memory system with a memory controller. The memory module comprises a module control device to receive command signals from the memory controller and to output module C/A signals and data buffer control signals. The module C/A signals are provided to memory devices organized in groups, each group including at least one memory device, while the data buffer control signals are provided to a plurality of buffer circuits to control data paths in the buffer circuits, a respective buffer circuit corresponding to a respective group of memory devices. The plurality of buffer circuits are distributed across a surface of the memory module such that each data buffer control signal arrives at the plurality of buffer circuits at different points in time. The plurality of buffer circuits include clock regeneration circuits to regenerate a clock signal received from the module control device and to provide regenerated clock signals to respective groups of memory devices.

A memory system of a high-speed operation can be realized by reducing an influence of reflection signals etc. caused by branching and impedance mismatching in various wirings between a memory controller and a memory module, and an influence due to transmission delays of data, command/address, and clocks in the memory module. To this end, a memory system comprises a memory controller and a memory module mounted with DRAMs. A buffer is mounted on the memory module. The buffer and the memory controller are connected to each other via data wiring, command/address wiring, and clock wiring. The DRAMs and the buffer on the memory module are connected to each other via internal data wiring, internal command/address wiring, and internal cock wiring. The data wiring, the command/address wiring, and the clock wiring may be connected to buffers of other memory modules in cascade. Between the DRAMs and the buffer on the memory module, high-speed data transmission is implemented using data phase signals synchronous with clocks.

Methods and systems for enumerating digital circuits in a system-on-a-chip (SOC) are disclosed. The method includes incrementing an enumeration value received from a previous enumerable instance to uniquely identify an immediately adjacent enumerable instance of a plurality of enumerable instances in a daisy chain configuration.

Methods and systems for enumerating digital circuits in a system-on-a-chip (SOC) are disclosed. The method includes incrementing an enumeration value received from a previous enumerable instance to uniquely identify an immediately adjacent enumerable instance of a plurality of enumerable instances in a daisy chain configuration.

Methods and systems for enumerating digital circuits in a system-on-a-chip (SOC) are disclosed. The method includes incrementing an enumeration value received from a previous enumerable instance to uniquely identify an immediately adjacent enumerable instance of a plurality of enumerable instances in a daisy chain configuration.

A data interface circuit wherein calibration adjustments for data bit capture are made without disturbing normal system operation, is described. A plurality of DLL capture and delay circuits for sampling a trained optimal sampling point as well as leading and trailing sampling points are defined. A first stream of data bits is input to the data interface circuit and using a first calibration method, a first optimal sampling point for sampling the data bits input is established. A second stream of data bits is input to the data interface circuit during normal system operation. A second calibration method is performed that is different from the first, the second calibration method being performed whereby: at least one reference data path is established for sampling transition edges of the second stream of data bits input to the data interface during normal system operation. Several fringe timing points are sampled, whereby several of the plurality of fringe timing points are associated with each of the transition edges of the second stream of data bits input to the data interface circuit. The drift amount is compared with a drift correction threshold value and the first optimal sampling point is shifted in time by the drift amount to revise the first optimal sampling point.

Methods and systems for enumerating digital circuits in a system-on-a-chip (SOC) are disclosed. The method includes incrementing an enumeration value received from a previous enumerable instance to uniquely identify an immediately adjacent enumerable instance of a plurality of enumerable instances in a daisy chain configuration.

A multi-image sensor system includes data, clock, and control buses, an application processor connected to the data bus and the clock bus, and image sensors connected in a daisy chain using the control bus. A first one of the image sensors configured as a master outputs image data to the data bus, outputs a first clock signal to the clock bus, and sends a control signal to a second one of the image sensors in the daisy chain through the control bus. The control signal has a first logic state when output of the first image data starts and a second other logic state when output of the first image data ends. The second image sensor connects itself to the data bus and the master disconnects itself from the data bus according to a state of the first control signal.